Laurie Anne Walden, DVM
Vaccines for dogs and cats are safe, especially compared with the risk of disease. Most animals don’t have any untoward symptoms after receiving a vaccine. But vaccines, like any other medicine, can have some side effects.
Vaccination produces an immune response, and inflammation is part of the immune response. Most of the symptoms (if any) that animals have after vaccination are caused by normal inflammation, meaning that the immune system is acting the way it’s supposed to act when it’s stimulated.
Allergic (hypersensitivity) reactions to vaccines are uncommon in dogs and cats but can be serious. These reactions are caused by an inappropriate immune response. The most severe type of hypersensitivity reaction is anaphylaxis, which can be life threatening.
In one study of dogs in the United States, the rate of vaccine-associated adverse events, including everything from normal inflammatory responses to anaphylaxis, was 0.38% (38 events per 10,000 vaccine doses). Anaphylaxis accounted for 1.7% of the adverse events. The risk of adverse events was highest in small-breed dogs and dogs who received multiple vaccines at the same time.
These are some of the common mild vaccine effects you might notice in your dog or cat. In most cases it’s safe to monitor these symptoms at home. If any of these symptoms last longer than a day or if your pet seems very uncomfortable, contact your veterinarian.
More Serious Symptoms
Allergic reactions to vaccines appear minutes or several hours after vaccination. Anaphylaxis can start with these symptoms and is a medical emergency. Seek veterinary care right away if your pet has any of these symptoms.
Lumps at Injection Sites
Most small, firm lumps at vaccine injection sites are caused by inflammation and resolve in a couple of weeks without treatment. An injection-site lump or swelling that is still present after 3 weeks or is enlarging should be checked by a veterinarian. Injection-site cancer is rare but can happen in cats (vaccine protocols and formulations for cats minimize this risk as much as possible).
Vaccines could—at least in theory—be linked to autoimmune diseases, in which the immune system targets cells of the body. Immune-mediated hemolytic anemia (affecting red blood cells) and thrombocytopenia (affecting platelets) occur in animals, but the association of these disorders with vaccination isn’t clear. The presence of an autoimmune disease would affect future vaccination decisions for the animal, though.
If Your Pet Has Had a Vaccine Reaction
Tell your veterinarian if your pet has had any vaccine-related symptoms. Your veterinarian will determine if your pet most likely had a normal inflammatory response or an allergic reaction. The decision on how to proceed with future vaccinations depends on the symptoms, the animal’s overall health, and the animal’s individual risk for vaccine-preventable diseases.
Depending on the circumstances, options for future vaccinations might include dividing vaccines among several visits instead of giving multiple vaccines all at once, giving medication (like an antihistamine) before vaccination, using a different type of vaccine, or discontinuing a vaccination. Vaccine titers—levels of antibody in the blood—indicate whether an animal is likely to still be protected by earlier vaccines, so titer testing can replace vaccination in some cases.
Some of these options don’t apply to rabies vaccination, which is mandated by law. In North Carolina and South Carolina, as in many states, veterinarians cannot give medical exemptions for rabies vaccination, and rabies antibody titers can’t be used instead of vaccination.
1. Moore GE, Guptill LF, Ward MP, et al. Adverse events diagnosed within three days of vaccine administration in dogs. J Am Vet Med Assoc. 2005;227(7):1102-1108. doi:10.2460/javma.2005.227.1102
2. Tizard IR. Adverse consequences of vaccination. Vaccines for Veterinarians. 2021;115-130.e1. doi:10.1016/B978-0-323-68299-2.00019-8
3. AAHA canine vaccination guidelines: vaccine adverse reactions. American Animal Hospital Association. Accessed August 27, 2021. https://www.aaha.org/aaha-guidelines/vaccination-canine-configuration/frequently-asked-questions/how-can-adverse-reactions-be-managed/
4. Rabiesaware.org. Accessed August 27, 2021. http://www.rabiesaware.org/
Photo by Raghavendra V. Konkathi on Unsplash
Laurie Anne Walden, DVM
Most skin lumps in dogs are benign. In cats, skin masses are more likely to be malignant. It’s impossible to know if a mass is benign or malignant just by looking at it and feeling it. For diagnosis, a sample of cells from the mass must be examined under a microscope.
Veterinarians use either fine-needle aspiration or biopsy to take samples from skin masses. Fine-needle aspiration is a quick technique that doesn’t require anesthesia. The veterinarian uses a syringe and needle (about the same size used for dog and cat vaccines) to remove a small sample from the mass. The sample is transferred to a microscope slide and either checked at the veterinary clinic or sent to a laboratory for a pathologist to evaluate.
Biopsy is the removal of a section of a mass—or an entire mass, if it’s small—for submission to a laboratory. Biopsy requires at least local anesthesia; most patients need sedation or general anesthesia. Fine-needle aspiration doesn’t always yield enough cells for a definite diagnosis, so biopsy is necessary for some masses.
So when is it okay to just watch a lump to see if it gets bigger, and when should a lump be checked by a veterinarian? Masses that fit these criteria should be evaluated by aspiration or biopsy:
The advantage of evaluating masses while they’re small is that malignant skin tumors can often be cured if they’re removed early. Larger masses are harder to remove completely. Some types of skin cancer spread through the body (metastasize) over time.
Benign masses don’t metastasize to other areas of the body or damage the tissues around the mass. Once diagnosed, they can be left alone unless they become painful or annoying to the animal (for example, if the surface becomes irritated or the mass grows large enough to interfere with movement). These are some of the most common benign skin lumps in dogs and cats:[2,3]
Malignant masses are cancerous and invade the surrounding tissues or metastasize throughout the body. Some malignant skin tumors that can’t be cured with surgery can be treated with radiation or chemotherapy. Animals with skin cancer benefit from referral to a veterinary oncologist. These are some of the malignant skin tumors that affect dogs and cats:[2,3]
1. Ettinger S. See something, do something. Why wait? Aspirate. In: Proceedings of the NAVC Conference, Volume 30: Small Animal and Exotics. NAVC; 2016:720-722.
2. Gear R. Lumps and bumps: common skin tumors. British Small Animal Veterinary Congress 2008. Veterinary Information Network. Accessed August 3, 2021. https://www.vin.com/apputil/content/defaultadv1.aspx?id=3862939&pid=11254&
3. Five types of skin cancer in dogs. NCSU College of Veterinary Medicine. Accessed August 3, 2021. https://cvm.ncsu.edu/wp-content/uploads/2018/03/5-Types-of-Tumors.pdf
Photo by Anusha Barwa on Unsplash
Laurie Anne Walden, DVM
Motion sickness is common in dogs and cats and can cause significant anxiety in affected animals. The condition is usually associated with riding in a car, boat, or airplane. If your pet vomits during trips, contact your veterinarian for medical help.
Motion-related nausea is caused by stimulation of the vestibular system, a set of structures in the inner ear responsible for sense of balance and coordination of head and eye movements. Signals from the vestibular system are connected to the vomiting center in the brainstem.
Motion sickness is probably related to sensory conflict when input from the eyes (what the animal sees) doesn’t match motion that the vestibular system detects. Head movements that are jerky, inconsistent, or in the opposite direction of the body’s motion—all of which happen while riding in a vehicle—can trigger the neural signals that lead to vomiting.
Animals with motion sickness sometimes vomit before the vehicle is even moving because they’re anxious and scared. They’ve learned that riding in a vehicle makes them feel sick, so they develop fear of the vehicle itself, and that fear makes them vomit. Anxiety that’s not related to motion sickness can also cause vomiting, so animals who are afraid of car rides for other reasons might vomit even if they don’t really have motion-related nausea.
Animals with motion sickness don’t always vomit. Some of the symptoms of nausea and anxiety are more subtle. Watch for these symptoms in dogs and cats:
Diagnosing motion sickness is usually pretty straightforward: vomiting that happens only in moving vehicles is motion sickness. A thorough history can help determine whether the animal has motion-related nausea, anxiety, or both. Vomiting that continues longer than the vehicle ride or is accompanied by other symptoms, like stomach pain, should be investigated further.
Withholding food for a few hours before the animal travels is a good way to start but might only reduce the volume of vomit; it won’t help with anxiety. Puppies sometimes outgrow motion sickness, especially if they receive positive-reinforcement training for vehicle rides. Training improves anxiety-related symptoms in some adult animals too. However, many animals need medicine to help them deal with motion sickness.
Safe and very effective antinausea medicines for dogs and cats are available by prescription. A veterinarian can help decide whether a pet would benefit most from antinausea medicine, antianxiety medicine, or both.
Motion sickness remedies for humans are available without a prescription, and some of these can be used in dogs and cats. However, never give your pet any motion sickness remedy without talking to your veterinarian first. Some of the products for humans have unwanted effects in animals. Many “natural” remedies are either untested or not effective in animals, and some might even be unsafe.
1. Conder GA, Sedlacek HS, Boucher JF, Clemence RG. Efficacy and safety of maropitant, a selective neurokinin 1 receptor antagonist, in two randomized clinical trials for prevention of vomiting due to motion sickness in dogs. J Vet Pharmacol Ther. 2008;31(6):528-532. doi:10.1111/j.1365-2885.2008.00990.x
2. Graham H. Motion sickness in small animals: pathophysiology & treatment. Clinician’s Brief. June 2013. Accessed May 16, 2021. https://www.cliniciansbrief.com/article/motion-sickness-small-animals-pathophysiology-treatment
3. Coates JR. Motion sickness in animals. Merck Veterinary Manual. Updated March 2021. Accessed May 16, 2021. https://www.merckvetmanual.com/nervous-system/motion-sickness/motion-sickness-in-animals
4. Hickman MA, Cox SR, Mahabir S, et al. Safety, pharmacokinetics and use of the novel NK-1 receptor antagonist maropitant (Cerenia) for the prevention of emesis and motion sickness in cats. J Vet Pharmacol Ther. 2008;31(3):220-229. doi:10.1111/j.1365-2885.2008.00952.x
Image source: James Frewin via Unsplash
Laurie Anne Walden, DVM
Pancreatitis, or inflammation of the pancreas, is common in dogs and cats. Although some cases are relatively mild, pancreatitis is painful and can cause severe disease and even death. Pancreatitis can be triggered by eating a high-fat meal or table scraps, so be very cautious about sharing holiday food with your pets.
Pancreatitis is categorized as acute (a short course of disease that can be reversed) or chronic (long-term disease caused by permanent damage to pancreatic cells). These categories can overlap. Animals with repeated episodes of acute pancreatitis can develop chronic pancreatitis, and animals with chronic pancreatitis can have flares of acute disease. In cats, the chronic form is more common than the acute form.
The pancreas, which is located near the stomach and small intestine, produces digestive enzymes and insulin. Because of the anatomic location and functions of the pancreas, pancreatic disease doesn’t always happen in isolation. Diseases of the liver, bile duct, and small intestine affect the pancreas and vice versa. In cats, simultaneous inflammation of the liver, small intestine, and pancreas is called triaditis. Chronic pancreatitis is associated with diabetes mellitus and deficiency of digestive enzymes.
The cause of pancreatitis in dogs and cats is often not found. However, some risk factors make pancreatitis more likely:
The symptoms of pancreatitis vary according to disease severity and are not specific; many disorders can cause the same symptoms. Symptoms are usually more severe with acute pancreatitis than with chronic pancreatitis. Other disorders that accompany pancreatitis also contribute to the symptoms.
These are some of the symptoms of acute pancreatitis:
The symptoms of chronic pancreatitis are often vague and can be mistaken for other disorders. Animals with chronic pancreatitis might have these symptoms:
Diagnosing pancreatitis can be tricky, especially in animals with vague symptoms or multiple organ systems affected. Baseline bloodwork and urinalysis don’t necessarily give a diagnosis but help assess the patient’s overall health and reveal associated disorders. A diagnosis of pancreatitis is typically made with a combination of blood tests for pancreas-specific factors (like serum amylase, serum lipase, canine and feline pancreas-specific lipase, pancreatic lipase immunoreactivity, and trypsin-like immunoreactivity) and ultrasonography of the abdomen.
Animals with acute pancreatitis usually need to stay in the hospital for at least a few days. Treatment can include intravenous fluids, pain management, antiemetics to control vomiting, tube feeding, possibly antibiotics, treatment of the underlying cause (if known), and treatment of associated disorders. Patients are monitored closely for complications like organ failure and blood clotting disorders. Animals with recurrent acute pancreatitis, chronic pancreatitis, or triaditis might need long-term diet modification.[2,5]
The prognosis depends on disease severity. Patients with mild disease tend to recover well, but the prognosis is guarded for animals with severe pancreatitis.
1. Watson P. Pancreatitis in dogs and cats: definitions and pathophysiology. J Small Anim Pract. 2015;56(1):3-12. doi:10.1111/jsap.12293
2. Simpson KW. Pancreatitis and triaditis in cats: causes and treatment. J Small Anim Pract. 2015;56(1):40-49. doi:10.1111/jsap.12313
3. Lem KY, Fosgate GT, Norby B, Steiner JM. Associations between dietary factors and pancreatitis in dogs. J Am Vet Med Assoc. 2008;233(9):1425-1431. doi:10.2460/javma.233.9.1425
4. Xenoulis PG. Diagnosis of pancreatitis in dogs and cats. J Small Anim Pract. 2015;56(1):13-26. doi:10.1111/jsap.12274
5. Steiner JM. Pancreatitis in dogs and cats. Merck Veterinary Manual. Updated October 2020. Accessed December 22, 2020. https://www.merckvetmanual.com/digestive-system/the-exocrine-pancreas/pancreatitis-in-dogs-and-cats
Photo by Sebastian Coman Travel
Laurie Anne Walden, DVM
Diabetes mellitus is an endocrine disorder that leads to high levels of glucose (a type of sugar) in the blood. Diabetes is common in dogs and cats. November is Pet Diabetes Month, so this article is a brief overview of this complex disorder.
Carbohydrates in the diet are converted to glucose in the body. The hormone insulin helps move glucose from the bloodstream into cells, where glucose is a source of energy. Diabetes mellitus occurs either when the body doesn’t produce enough insulin or when the body can’t use insulin properly.
Insulin is made in the pancreas. Immune-mediated destruction of pancreatic cells or pancreatitis (inflammation of the pancreas) can reduce insulin production. Dogs and cats can also develop insulin resistance, in which the pancreas makes insulin but the body doesn’t respond normally to it. This type of diabetes, similar to type 2 diabetes in people, is the most common type in cats.
Obesity is a major risk factor for diabetes in dogs and cats. Obese cats are up to 4 times as likely as cats of ideal weight to develop diabetes. Other diseases, like hyperadrenocorticism (Cushing disease) and hypothyroidism in dogs, acromegaly in cats, dental disease, and kidney disease, are also associated with diabetes. Some medications, especially glucocorticoids like prednisone, increase the risk for diabetes. Breeds that are more prone than others to diabetes include beagles, Australian terriers, Samoyeds, keeshonds, and Burmese cats.
In animals with a high blood glucose level, excess glucose is excreted in the urine. Glucose in the urine acts as a diuretic, increasing urine volume. Animals with diabetes often develop urinary tract infections because of the sugar in the urine. When cells can’t use glucose properly for fuel, the body begins to break down fat and muscle. These changes in metabolism affect many organ systems. Uncontrolled diabetes can also lead to diabetic ketoacidosis, a potentially life-threatening complication.
These are some of the symptoms of diabetes:
Diabetes is diagnosed by blood and urine tests showing high glucose levels that persist on repeat testing. In cats, stress can increase the blood glucose level, so measurement of serum fructosamine (a protein that reflects average blood glucose levels over the previous week or so) can help with diagnosis. Full bloodwork, urinalysis, and urine culture are done to identify other conditions that might accompany or result from diabetes and complicate treatment.
Dogs and cats with diabetes are treated with insulin injections and diet modification. Oral medications for diabetes don’t work for dogs and aren’t very effective in cats, so all dogs and almost all cats with diabetes require insulin injections. The type and dose of insulin and the diet chosen depend on the individual patient and can change over time.
Other disorders can affect the body’s response to insulin and must also be identified and treated. Sick patients with ketoacidosis need intensive treatment in the hospital.
Treating diabetes requires significant pet owner commitment and regular monitoring. The injections must be given on a consistent schedule, and owners need to monitor their pet’s appetite and watch for signs of hypoglycemia (low blood glucose): sleepiness, weakness, stumbling, tremors, and seizures. In dogs and cats, blood glucose is monitored from time to time with a glucose curve, a series of glucose measurements over the course of a day, either at home or at the veterinary clinic. Insulin dose adjustments are generally based on glucose curve results, not on single spot checks of blood glucose.
In dogs, diabetes almost always requires lifelong insulin therapy. Some cats treated for diabetes undergo remission and no longer need insulin, especially if their blood glucose levels can be brought under control with insulin and diet early in the course of disease. The prognosis is generally good for dogs and cats with well-controlled diabetes.
1. Behrend E, Holford A, Lathan P, Rucinsky R, Schulman R. 2018 AAHA diabetes management guidelines for dogs and cats. American Animal Hospital Association. 2018. Accessed November 20, 2020. https://www.aaha.org/globalassets/02-guidelines/diabetes/diabetes-guidelines_final.pdf
2. Sparkes AH, Cannon M, Church D, et al; ISFM. ISFM consensus guidelines on the practical management of diabetes mellitus in cats. J Feline Med Surg. 2015;17(3):235-250. doi:10.1177/1098612X15571880
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Laurie Anne Walden, DVM
If your pet’s eye is red, have it checked by a veterinarian without delay. Eye redness is a nonspecific symptom. It’s nearly always impossible to tell whether a red eye is minor or serious without ophthalmic tests at a veterinary clinic. These are some of the conditions that cause red eyes in dogs and cats.
Conjunctivitis, called pinkeye in people, is inflammation of the tissue that lines the eyelids and covers the whites of the eyes. Causes of conjunctivitis in pets include environmental irritants, allergies, skin disease, dry eye, and (especially in cats) viral or bacterial infections. Some of the conditions that cause conjunctivitis also affect the eyelids and the cornea, the clear front part of the eye.
Corneal ulcers are defects on the surface of the cornea. In dogs and cats they can be caused by things poking the eye (like turned-in eyelashes, a foreign object under the eyelid, or being swatted in the face by a cat), infections, dry eye, disorders of corneal cells, and chronic eye exposure in flat-faced animals with shallow eye sockets. Corneal ulcers and scratches are painful. Some ulcers are shallow and heal fairly quickly with treatment. Others are deep and can perforate all the way through to the interior of the eye. Diagnosis requires applying an ophthalmic stain to highlight the corneal defect.
Trauma to the outer surface of the eye causes redness of the white part of the eye, similar to the redness caused by conjunctivitis. Blunt trauma to the head can cause bleeding inside the eye, which looks like dark red discoloration behind the cornea. Bleeding disorders and other conditions can also cause blood accumulation inside the eye.
Uveitis is inflammation of the interior of the eye. Uveitis doesn’t happen on its own; it’s a sign of another problem. Some of the diseases that cause uveitis affect the whole body: infections, tick-borne diseases, immune-mediated disorders, cancer, and so forth. Uveitis is also caused by eye disorders like cataracts. Uveitis is a painful condition that can lead to glaucoma. Diagnosis involves examination of the eye, measurement of eye pressure, and tests to find the underlying cause.
Glaucoma is a disease characterized by increased pressure within the eye. The condition is inherited in some dog breeds and is also caused by uveitis, lens luxation (lens slipping out of place), and cancer of the eye. Glaucoma is painful and leads to blindness. Sudden-onset glaucoma is a medical emergency if vision is to be saved.
Cherry eye is the common term for prolapse of the gland of the nictitating membrane, a pink membrane (sometimes with a dark edge) at the inner corner of the eye. A tear gland within this membrane can swell and protrude past the edge. The prolapsed gland looks like a round pink or red mass at the inside corner of the eye. This is the one type of “red eye” that doesn’t require an immediate visit to the veterinarian—unless other symptoms, like squinting or eye discharge, are also present. However, a prolapsed tear gland can cause eye irritation, and tumors in this area look similar, so it should still be checked out. Prolapsed tear glands are treated surgically.
Photo by Céline Harrand
Laurie Anne Walden, DVM
Otitis externa, or inflammation of the outer ear canal, causes itchy or painful ears and is common in dogs. Dogs with otitis externa often develop ear infections.
Otitis externa affects the part of the ear from the eardrum outward. Inflammation or infection that extends farther into the ear causes otitis media (middle ear disease) or otitis interna (inner ear disease).
Allergies to environmental substances (pollens, dust, etc) or to food ingredients are the most common causes of otitis externa in dogs. Other causes include parasites like ear mites, endocrine disorders like hypothyroidism, and immune system disorders.
Risk factors that make dogs more likely to develop otitis are long droopy ears, narrow ear canals, lots of hair in the ear canals, and growths in the ear canals. Plucking hair from the ear canals, cleaning the ears aggressively, and using harsh ear cleaners may damage the cells lining the ear canal and increase the risk for otitis externa.[1,2]
Depending on the cause, otitis externa can be a chronic problem that requires lifelong management. Dogs with allergies sometimes have flares of otitis even if the condition is under control most of the time.
Symptoms of external ear disease vary according to severity, individual dogs’ tolerance to discomfort, and whether infection is present. Most dogs with otitis externa have 1 or more of these symptoms:
Some dogs with long-term or recurrent otitis externa develop end-stage ear disease. These dogs have chronic ear pain (although they might not show obvious signs of pain), narrowed ear canal openings, hardened ear canals, and possibly hearing loss.
The diagnosis of otitis externa is usually made by physical examination and history. Cytology, or examination of material from the ear canal under a microscope, is used to diagnose infection, identify the type of infection (bacteria, yeast, or both), and monitor the response to treatment. Examination of the canal and eardrum with an otoscope is helpful but not always possible in dogs with painful ears unless they are sedated. Other diagnostic tests can include bacterial culture of ear canal contents and imaging studies like radiography or computed tomography. Your veterinarian might recommend additional tests to find the underlying cause if your dog has had multiple episodes of otitis externa.
Medications to treat ear infections include topical ear drops, oral medications, and medicated ear washes. The type of medication used depends on the type of infection and the severity of inflammation. The underlying cause of otitis is also treated as needed.
Many medications prescribed for ear infections contain anti-inflammatory drugs like corticosteroids. These medications reduce redness and itching, so the symptoms will improve before the infection has resolved. The best way to be sure the infection has actually cleared up is to follow your veterinarian’s dosing directions (how often and how long to use the medication) and to return for ear cytology rechecks as your veterinarian recommends.
For many dogs, especially those with allergies, otitis externa can’t be completely prevented. Work with your veterinarian to manage the factors that contribute to your dog’s otitis and watch for symptoms so you can catch ear infections early.
1. Bajwa J. Canine otitis externa - treatment and complications. Can Vet J. 2019;60(1):97‐99.
2. Paterson S. Topical ear treatment - options, indications and limitations of current therapy. J Small Anim Pract. 2016;57(12):668‐678. doi:10.1111/jsap.12583
Photo by Ryan Walton
Laurie Anne Walden, DVM
Mast cell tumors are common in dogs and somewhat common in cats. In dogs, mast cell tumors are usually lumps on or under the skin. Mast cell tumors in cats can affect the skin or the internal organs.
Mast cells are a normal part of the immune system. They are most often found in the skin, digestive tract, and other areas that are exposed to substances from the environment. Mast cells are full of granules that contain histamine and other chemicals that are released as part of allergic and inflammatory responses. You’ve seen mast cells in action yourself: the itchy lump you get after a mosquito bite is caused by mast cells in the skin releasing histamine and other substances. Mast cell tumors are cancerous growths made up of mast cells.
Signs in Dogs
Mast cell tumors are most common in older dogs but occur in dogs of all ages. Dogs of any breed can develop mast cell tumors. Breeds at higher risk than others include retrievers, shar-peis, and brachycephalic (flat-faced) breeds like boxers, pugs, and Boston terriers.
In dogs, mast cell tumors can look similar to other conditions. Some look and feel just like benign fatty lumps. Mast cell tumors in dogs vary in appearance and behavior. A mast cell tumor might be a smooth, round, raised skin lump; a red, itchy lump; or a soft lump under the skin. Some are solitary growths, and some are clusters of lumps or small bumps. Some grow very slowly, with no apparent change for months; others grow quickly. Mast cell tumors sometimes get bigger (or pinker or itchier) and then return to their normal appearance. This change happens when they release histamine. More serious effects of histamine release include decreased appetite, vomiting, diarrhea, blood in the stool, and collapse.[1,2]
Signs in Cats
Most cats with mast cell tumors are older, although an atypical form is most common in young cats. Siamese may be more likely than other cat breeds to have mast cell tumors.
In cats, the signs of mast cell tumors depend on their location (skin or internal organs) and the tumor subtype, which determines how aggressive they are. As in dogs, mast cell tumors in cats can mimic other conditions and do not all look and behave the same way. Mast cell tumors in the skin can be smooth, round growths or flat red patches, and they might grow quickly or very slowly. Mast cell tumors inside the body most often affect the spleen or digestive tract and can cause decreased activity, decreased appetite, vomiting, diarrhea, and other general signs of illness.[1,3]
Most mast cell tumors of the skin can be diagnosed during a veterinary appointment with a needle aspirate, in which a small sample of cells is removed with a needle and syringe and examined under a microscope. Because putting a needle in a mast cell tumor can cause histamine release, veterinarians often give an antihistamine when they aspirate a mast cell tumor.
A needle aspirate can show that a patient has a mast cell tumor, but it doesn’t give enough information to know the prognosis. Some mast cell tumors are single lumps that don’t spread to lymph nodes or distant parts of the body. Others are more invasive and have a high risk of spreading through the body. Currently the only way to know the grade or type of a mast cell tumor, and hence the prognosis, is by surgically removing all or part of the tumor and sending this biopsy sample to a laboratory for analysis.
Patients with high-grade or aggressive mast cell tumors, including cats with mast cell tumors in internal organs, benefit from further tests to find out whether the cancer has spread or is causing other problems. This workup can include blood and urine tests, lymph node aspiration, imaging (such as ultrasound or computed tomography), and bone marrow analysis. Whether to do these tests before or after biopsy depends on the patient and the tumor.
Surgical removal is recommended for most mast cell tumors and might be the only treatment (other than antihistamines) needed for low-grade mast cell tumors of the skin. Cancerous mast cells extend past the edges of the visible lump, so a wide area of normal-appearing skin around the tumor must be removed. The biopsy report indicates whether all of the tumor was removed during the procedure.
Chemotherapy, other medications, and radiation therapy are available for patients with aggressive tumors, cancer in internal organs, tumors in areas where wide removal isn’t possible, or tumors that aren’t completely removed during surgery. Your veterinarian is likely to recommend referral to an oncologist if your pet might need these types of treatment.
The prognosis is good for patients with mast cell tumors that haven’t spread and are completely removed with surgery, radiation therapy, or both. These patients sometimes develop another mast cell tumor later, so all new lumps warrant a visit to the veterinarian. For patients with other types of mast cell tumor, the prognosis depends on tumor grade, location, and response to treatment.
1. Blackwood L, Murphy S, Buracco P, et al. European consensus document on mast cell tumours in dogs and cats. Vet Comp Oncol. 2012;10(3):e1-e29. doi:10.1111/j.1476-5829.2012.00341.x
2. Couto CG. Mast cell tumors: to cut or not to cut. Paper presented at: 2018 Michigan Veterinary Conference; January 26-28, 2018; Lansing, Michigan. Accessed February 14, 2020. https://www.michvma.org/resources/Documents/MVC/2018%20Proceedings/couto_04.pdf
3. Henry C, Herrera C. Mast cell tumors in cats: clinical update and possible new treatment avenues. J Feline Med Surg. 2013;15(1):41-47.
Photo by JC Gellidon
Laurie Anne Walden, DVM
The anal sacs, or anal glands, are a pair of small sacs located under the skin on each side of the anus of dogs and cats. These sacs contain smelly material that is normally squeezed out when an animal passes stool. If your dog is scooting his bottom across the floor, he might have an impacted (clogged) anal sac.
Anal Sac Anatomy
Anal sacs lie between the anal sphincter muscles, the circular muscles that close the anus. Each sac has a small duct that leads to an opening in the skin next to the anus. Anal sac material is liquid or pasty in consistency, ranges in color from cream to brown, and has a characteristic fishy odor.
The function of anal sacs is not entirely clear but might have to do with scent marking and communication.
Symptoms of Anal Sac Problems
Dogs and cats with anal sac disorders have symptoms of anal discomfort (these are more common in dogs):
Other problems, like parasites, fleas, and orthopedic pain, can cause some of the same symptoms.
Types of Anal Sac Disorders
The most common anal sac problem by far is impaction, in which an anal sac can’t empty on its own and material remains in the sac. Scooting the bottom on the floor and licking the anal area are typical symptoms. Impaction happens more often in small dogs than in large dogs or cats. The causes of impaction are not fully known. Many dogs go through their entire lives without ever having impacted anal sacs; others experience it regularly. Allergies, skin disease, and changes in stool consistency might make a dog more likely to have clogged anal sacs.
Impacted anal sacs can become inflamed, a condition called anal sacculitis. Anal sacculitis causes painful, swollen sacs and often redness of the skin around the anus.
Infected anal sacs can form abscesses. An anal sac abscess first appears as a painful swelling beside the anal opening. It may rupture through a skin wound that drains pus or blood next to the anus.
Anal gland tumors are less common than impaction, inflammation, or infection. They can cause swelling, bleeding, or discomfort in the anal area.
Veterinarians usually manage an impacted anal sac by gently expressing the material out of the sac. This process can be uncomfortable for the patient, especially if the material is too thick or dry to be easily removed. Some patients benefit from anal sac flushes or warm compresses applied to the anal area. Anal sac inflammation and infection are typically treated with antibiotics and pain relievers. The anal sacs can be surgically removed in patients with anal sac cancer or as a last resort for patients with other anal sac problems. (Surgical removal is not generally recommended for patients with simple anal sac impaction because of the possibility of complications after surgery.)
What You Should Do
If your dog or cat doesn’t have any symptoms of anal sac trouble and your veterinarian hasn’t found a problem, you don’t need to do anything in particular. There’s no need to change your pet’s diet or have the anal sacs expressed if they’re working normally. But be aware of the signs of anal sac impaction so you can have this uncomfortable problem taken care of before it becomes more painful for your pet.
Photo by Sheri Hooley
Laurie Anne Walden, DVM
Kennel cough, the common term for canine infectious respiratory disease (or infectious tracheobronchitis), is a contagious disease that causes a hacking cough. The infection spreads quickly among dogs. Kennel cough is usually a mild illness, but some dogs develop more serious disease.
Many bacteria and viruses cause canine infectious respiratory disease. Most dogs with the disease are infected with more than 1 organism at the same time.[1,2] Some of the organisms involved are the following:
Not all dogs get sick after being exposed to an agent that can cause respiratory disease. Some of these organisms are unlikely to cause illness on their own but can cause symptoms when combined with other organisms. Whether a dog develops respiratory disease is also affected by environmental factors (such as crowding and poor ventilation) and the dog’s immune system.
Kennel cough spreads through respiratory secretions from an infected dog. Dogs with no symptoms at all can spread the infection. Droplets containing bacteria or viruses become airborne after a dog coughs or sneezes and are deposited on surfaces, water bowls, toys, and other objects. The higher the number of dogs housed together, the higher the chance of a dog coming into contact with infected respiratory secretions.
Crowding increases stress, which reduces a dog’s protective immune response against infection. Some infectious agents can hinder the immune response, making infection with additional organisms more likely.
Bordetella bronchiseptica can infect cats and possibly humans. Infection in humans is probably of most concern in people with impaired immune function.
Because of the variety of organisms and differences in individual dogs, symptoms can vary. Typical symptoms of the mild form of disease include the following:
Some dogs, especially young puppies, elderly dogs, and dogs with poor immune function, develop more severe bronchitis and pneumonia. These dogs have more serious symptoms:
For dogs with mild disease, kennel cough is usually presumed from physical examination findings and history of exposure to other dogs. Dogs with a persistent cough or signs of more serious disease need diagnostic testing, which can include chest radiographs, blood tests, and (in some cases) tests to identify the organisms involved.
Treatment decisions are based on the severity of the illness and the dog’s environment. Mild cases of kennel cough often resolve on their own, so dogs with mild disease might need only supportive care (good nutrition, limited activity, and a warm place to rest indoors). Some dogs benefit from treatment with an antibiotic active against Bordetella. Most dogs with kennel cough should not receive cough suppressants. Dogs with more severe disease need more intensive treatment. The treatment for dogs in an environment with a high risk of disease spread (like a shelter) may be different from the treatment chosen for a pet living at home.
Vaccines help control canine infectious respiratory disease. No single vaccine can entirely prevent kennel cough, but vaccinations protect dogs against some of the organisms and reduce the severity and spread of disease.
A combination vaccine including canine distemper virus, canine adenovirus type 2, and sometimes canine parainfluenza virus is recommended for all dogs. Puppies receive this vaccine as part of the puppy vaccine series. Adult dogs should have booster vaccinations (or antibody titer tests).
A vaccine against Bordetella bronchiseptica, sometimes also including canine parainfluenza virus, is recommended for dogs whose lifestyle puts them at risk for infection. The Bordetella vaccine is given in the nose, in the mouth, or by injection, depending on the formulation. Vaccines against canine influenza virus are also available. The decision to give a dog Bordetella and flu vaccines depends on the dog’s lifestyle and possibly on geographic area. Talk to your veterinarian about these vaccines if your dog goes to boarding kennels, doggie daycare, dog parks, dog shows, groomers, shelters, or other areas where dogs gather.
Because infectious respiratory disease is so contagious, dogs with symptoms should be kept away from other dogs as much as possible. Washing hands, bowls, dog toys, and clothing can reduce the risk of spreading the infection to other dogs.
1. Schulz BS, Kurz S, Weber K, Balzer HJ, Hartmann K. Detection of respiratory viruses and Bordetella bronchiseptica in dogs with acute respiratory tract infections. Vet J. 2014;201(3):365-369.
2. Hurley K, Aziz C. Canine infectious respiratory disease complex (CIRDC) - diagnosis and treatment; prevention and management. Pacific Veterinary Conference 2015. Veterinary Information Network website. https://www.vin.com/doc/?id=6789809. Accessed December 6, 2019.
3. Canine infectious respiratory disease complex (CIRDC, a.k.a. “kennel cough”). University of Wisconsin-Madison Shelter Medicine website. https://www.uwsheltermedicine.com/library/resources/canine-infectious-respiratory-disease-complex-a-k-a-kennel-cough. Published July 2015. Accessed December 6, 2019.
4. Kuehn NF. Tracheobronchitis in small animals. Merck Veterinary Manual website. https://www.merckvetmanual.com/respiratory-system/respiratory-diseases-of-small-animals/tracheobronchitis-in-small-animals. Accessed December 6, 2019.
5. 2017 AAHA canine vaccination guidelines. American Animal Hospital Association website. https://www.aaha.org/aaha-guidelines/vaccination-canine-configuration/vaccination-canine/. Published September 7, 2017. Updated February 3, 2018. Accessed December 6, 2019.
Photo by Hannah Lim
Laurie Anne Walden, DVM
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