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Hamster Health Center

Knowing these hamster facts about health concerns could help you recognize a sick hamster so you can get it medical help more quickly.

By Kevin Wright, DVM, DABVP (reptile and amphibian) with excerpts from the Popular Critters Series magabook Hamsters with permission from its publisher, BowTie magazines, a division of BowTie Inc.
Posted: October 6, 2011, 3:25 p.m. EDT

hamster health center

Hamsters sometimes get sick or injured. It can happen to hamsters given the best of care. Veterinary care for sick hamsters or injured hamsters has come a long way. Want to know all about hamster health concerns? Check out the following list of hamster illnessesand injuries to learn more about some common hamster health concerns before your hamster gets sick. If your hamster is currently sick or injured, immediately contact a veterinarian experienced in caring for hamsters.

If you don't know an illness or injury by name, check out our list of signs of illness in hamsters and possible causes, click here>>

Scroll down or choose a hamster care or health concern from this list. This page has hamster facts and information for hamster ilnnesses and injuries beginning with the letters A through H. The links below take you to any of the listed hamster illnesses and injuries. If you wish to scroll through the hamster illnesses and injuries named I through Z on Page 2, click here>>

Anal Atresia
Atrial Thrombosis
Behavioral Abnormalities
Cheek-Pouch Problems
Congestive Heart Failure
Cutaneous Abscess
Death and Euthanasia

Diabetes and Kidney Disease
Gastroenteritis (Diarrhea, Wet Tail, Bloating)
Giardia sp.
Hair Loss, Hair Thinning (alopecia)
Itching (Pruritus)
Mange, demodecosis
Physical Trauma (Bites, Falls)
Reproductive Issues (Pyometra, Neutering, Polycystic Ovaries)
Respiratory Infections (Pneumonia, Colds, Sniffles)
Scent Gland Irregularities
Tritrichomonas sp.
Tumors (Lymphosarcoma, Hamster Polyomavirus And Others)
Tyzzer's Disease

Hamster-Knowledgeable Vet
Use these tips to find a veterinarian for your hamster. Click Here>>

Amyloidosis (Back to Top)
Amyloidosis is a poorly understood disease that can cause debilitating illness in hamsters and other animals. Amyloid is a protein that is formed when a hamster’s immune system is over-stimulated. Often this is the result of an infection that has been left untreated, such as a bladder infection or tooth root abscess. It is more common in older female hamsters, particularly intact females that have developed ovarian or uterine disease. This abnormal immune response causes amyloid to accumulate in internal organs like the heart, liver and kidneys. Over time, these organs no longer function normally. A hamster may lose its appetite and develop a swollen, fluid-filled abdomen. The hamster may have trouble breathing due to the fluid pressing on its diaphragm.

If the kidneys are affected, your veterinarian may find that the urine has abnormal levels of protein and a low concentration of salts (i.e., a low specific gravity). The urine may also show signs of infection with white blood cells and casts. A blood sample may show low albumin, which happens with liver and kidney amyloidosis. An ultrasound may reveal abnormal liver and kidneys, as well as an abnormal heart.

Unfortunately, there is no cure for amyloidosis. Short-term medical care may include diuretics to help move fluid out of the abdomen, but this is not effective if the kidneys are failing. Some medications may help increase the affected heart’s strength temporarily. Euthanasia should be considered for those hamsters with a poor quality of life. 

Anal Atresia (Back to Top)
This congenital condition occurs in newborn hamsters but is rare. Symptoms can include a lack of bowel movements or any of the usual signs of illness. With this condition, incomplete bowel development prevents the hamster from defecating. Bloating of the abdomen follows and, if left untreated, death ensues. Some cases can be repaired surgically, if identified quickly. 

Atrial Thrombosis (Back to Top)
Hamsters are prone to heart disease. Atrial thrombosis occurs when a clot forms in one of the large, thin-walled chambers of the heart, individually known as atrium and collectively as atria. It occurs most commonly in the left atrium, where oxygen-rich blood from the lungs returns to the heart and is passed to the left ventricle, where it is pumped out to the body. This is the most common cause of spontaneous death in hamsters between 1 and 2 years old. There is no known preventive. It is rarely diagnosed in a living hamster, and no known treatments have been published. 

Behaviorial Abnormalities (Back to Top)
Occasionally hamsters are born with behavioral abnormalities such as repetitive, compulsive circling or back-flipping. These conditions are not well understood, but are probably caused by incorrect neurological development and may be genetic. These conditions seem to be more prevalent in dwarf hamsters than Syrian hamsters.

There is no cure for these problems. Affected hamsters may be untamable, aggressive or have reduced life expectancy. Others, however, are normal in all other respects. Regardless of the severity, affected hamsters should never be bred. 

Cardiomyopathy (Back to Top)
Cardiomyopathy is a condition where the heart’s chambers may become very thin-walled and floppy or extremely thick-walled and rigid. In Syrian hamsters, the thin-walled form called dilated cardiomyopathy has been extensively studied and the gene responsible has been isolated. The affected hamster heart cannot pump effectively and leads to poor circulation, which in turn causes difficulty breathing from fluid build-up in the lungs, weakness due to reduced levels of oxygen in the blood, and rapid tiring during normal activities, such as walking or even eating.

An echocardiogram, or ultrasound, of the hamster’s heart may diagnose this condition, but often the diagnosis rests on a combination of signs and findings of a heart murmur and enlarged heart on radiographs.

Management may include diuretics such as furosemide to help move fluid out of the lungs and abdomen, certain medications that increase the strength of the heart’s contractions and supplemental oxygen in a home-made oxygen chamber as needed. Even with these efforts, a hamster may only live a few days to a few weeks following diagnosis. Survival for more than three months is extremely rare.

Experimental gene therapy has extended the lives of hamsters with genetically caused cardiomyopathy, but this is not an option for pet hamsters.  

Cataracts (Back to Top)
Elderly hamsters of all species can develop cataracts, which appear as a developing “milkiness” of the eye. Eyesight gradually fades, but hamsters are otherwise unaffected and no treatment is required.

Cheek-Pouch Problems (Back to Top)
Normal hamster behavior includes carrying food around in engorged cheek pouches. When full, these can extend back beyond the shoulders and look extremely large and ungainly. Sharp or inappropriate food, including sweet or sticky substances, can scratch or stick in cheek pouches, causing an infection and interfering with eating. 

It’s easy to miss the symptoms of cheek-pouch infection. The history of care — how and what the hamster was fed, if inappropriate bedding was used — usually provides the best clues. Physical signs include asymmetrical swelling, a change in appearance of the pouches, loss of appetite or any general signs of illness — each could indicate a cheek-pouch problem. 

If you think your hamster’s pouches are unusually swollen or damaged, take it to the vet. He or she can flush out the pouches and treat any damage or infection. To help avoid this condition, never give hamsters sweets, chocolate or sharp hay and bedding.  

Collapse (Back to Top)
If you find your hamster collapsed or unresponsive, take it to your vet immediately. Describe anything unusual you may have noticed. This emergency can have several causes including heatstroke, hypothermia, infection, shock, poisoning, heart attack, stroke or epilepsy. Your veterinarian will know how to treat these. 

If the ambient temperature drops severely (below 40 degrees Fahrenheit), all hamster species are capable of going into hibernation. This isn’t a collapse, but a natural physiological response. Indoor hamsters kept at regular room temperature (72 degrees Fahrenheit) won’t hibernate. To waken a hibernating hamster, gradually warm the air to regular room temperature.  

Congestive Heart Failure (Back to Top)
A hamster’s heart may not pump normally for a variety of reasons including a birth defect, an injury or infection, or conditions like amyloidosis and cardiomyopathy. When this happens, fluid leaks out of the blood and into the surrounding tissues causing edema, fluid in the lung and ascites (fluid in the abdomen), and it is termed congestive heart failure (CHF). This in turn creates difficulty breathing and moving oxygen throughout the body. Signs of heart disease include coughing, difficulty breathing, weakness, sleepiness, a swollen pendulous abdomen, and rapid tiring out from normal activities. Sometimes the tongue and gums may look slightly gray or blue instead of a bright pink.

As with dilated cardiomyopathy, a diagnosis of CHF requires a radiograph and often an echocardiogram, or ultrasound of the hamster’s heart. An enlarged heart, especially where the lungs and abdomen show signs of fluid, support the diagnosis of congestive heart failure. Many conditions cause CHF, so a confirmed diagnosis is often only obtained by a pathologist examining the heart tissue during a necropsy of a deceased hamster.

Management of CHF may include diuretics such as furosemide to help move fluid out of the lungs and abdomen, certain medications that increase the strength of the heart’s contractions and supplemental oxygen in a home-made oxygen chamber as needed. Even with these efforts, a hamster may only live a few days to a few weeks following diagnosis. Survival for more than three months is extremely rare. 

Conjunctivitis (Back to Top)
A hamster may start to squint in one or both eyes as a result of an infection of the lining of the eyelids and tissues surrounding the eyeball. This infection, known as conjunctivitis, may result from viruses, chlamydophila, bacteria and many other kinds of infectious micro-organisms. It sometimes happens from dust or foreign objects irritating the eye, and sometimes it is the result of fighting. It may also be caused by a tooth root infection.

Sometimes the tissue surrounding the eye gets swollen and red, a condition often known as “pink eye.” You may notice a thick discharge or crust around the eye and the hamster may be unable to open one or both eyes. Some hamsters may also sneeze and have a nasal discharge, and may go on to develop an upper respiratory infection.

Your veterinarian may do some tests to make sure there is not an injury to the surface of the eye (such as a corneal ulcer) or other condition that mimics conjunctivitis. Sometimes the eye crust and closed eyes are signs of dehydration and not true conjunctivitis.

Conjunctitivis can spread to other hamsters, so make sure the affected hamster is isolated from others if it is a social species, such as one of the dwarf hamster species like Roborovskis, Campbell’s or Winter Whites. Practice proper hand-washing after handling the hamster. Watch other hamsters closely for squinting or crusty eyes.

Conjunctivitis often responds well to eye medications but some forms of it, such as that caused by chlamydophila, may need oral antibiotics for a few weeks for successful treatment. Gently clean away any discharge as needed with a warm, wet cottonball. Some hamsters need pain-relieving medications, either eyedrops such as flurbiprofen or oral medications like meloxicam, to feel better quickly. Some hamsters may need syringe-feeding and drinking until their eyes are open and they can find these on their own. 

Cutaneous Abscess (Back to Top)
A hamster may develop a pocket of pus in the skin, which is called cutaneous abscess. These bacterial infections are often the result of fighting but sometimes may be secondary to a piece of shavings or other foreign object sticking into the hamster’s skin. Sometimes sharp seeds, such as sunflower seeds, may injure the lining of the cheek pouch and lead to an abscess. Sometimes an abscess can be the result of a behavioral condition, such as excessive scratching. Occasionally, some of the scent glands on a hamster may become abscessed.

An abscess may need to be surgically drained and cleaned in order to heal. Your veterinarian may have you clean the wound with dilute povidone iodine in warm water. Antibiotics and something to relieve pain and swelling, like meloxicam, may be prescribed. Never use Neosporin or other antibiotic ointments containing neomycin on a hamster’s abscess, as this can cause a life-threatening diarrhea. 

Death and Euthanasia (Back to Top)
Sometimes a hamster will have an incurable condition or injury that severely reduces its quality of life or causes it pain. In this difficult situation, some people may choose to have their vet painlessly put their pet to sleep.

This is never an easy decision and it should be made in your own time, after discussion with your vet. You need to feel good about the decision you make, so raise any questions or concerns that trouble you. If you lose a pet, your vet can explain the grieving process to you to help you cope with normal feelings of guilt and loss.  

Diabetes and Kidney Disease (Back to Top)
Diabetes in hamsters is usually hereditary, but it’s suspected that an unknown environmental element may sometimes be a cause. Kidney disease in hamsters can have many causes, such as genetics, diet or infection. Both conditions can also be age-related. Complex research into this is ongoing.

Excessive drinking and increased urination can be signs of diabetes or kidney disease in hamsters. Some Campbell’s hamsters seem prone to diabetes, which comes on after a few months of life. Kidney problems are more common in elderly hamsters of any species.

You may initially notice that your hamster’s cage bedding is wetter than normal, and the urine may smell. The smell may be sweet, pungent or the same as usual. Your vet can test your hamster’s urine and blood to determine what is wrong. Diabetes and kidney disease can be fatal if not treated, but some hamsters respond very well to low-sugar or low-protein diets offered under expert guidance.

Exophthalmos (Back to Top)

Hamster eyes bulge slightly, but exophthalmos caused the right eye of this hamster to bulge too much.
Click image to enlarge.
Hamsters sometimes develop bulging eyes, sometimes only on one side but often involving both eyes. Exophthalmos involving both eyes often results from a hamster that is held too tightly or has a head injury. Exophthalmos involving only one eye is commonly due to an infection of the eye, an infection behind the eye, known as a periorbital abscess, or a tooth-root abscess. Other possible causes include tumors, glaucoma and high blood pressure.

If you think your hamster has exophthalmos, make sure the eye stays moist until you can get to a veterinarian. Artificial tears or eye lubricants safe for people are available over-the-counter, and may be applied every few hours. Your veterinarian may need to sedate or anesthetize your hamster to better assess its condition. Some infections and abscesses respond well to oral and ophthalmic antibiotics and oral meloxicam (a nonsteroidal anti-inflammatory that relieves pain and swelling) while other infections may need surgery to remove the pus or infected tooth. Some tumors respond to corticosteroids and oral chemotherapy drugs like cyclophosphamide. Glaucoma may be managed with drops. Sometimes an exophthalmic eye must be removed.

Make sure anyone who handles your hamster knows how to do so safely to prevent exophthalmos and other injuries.

Gastroenteritis (Diarrhea, Wet Tail, Bloating) (Back to Top)

This hamster is suffering from severe diarrhea, also known as wet tail.
Click image to enlarge.
Hamsters are hind-gut fermenters and rely on their natural gut bacteria being balanced for health. Gastroenteritis and diarrhea are often caused by disruption of these natural bacteria or infection by foreign material. 

Wet-tail is not a medical term, but describes one sign of watery diarrhea. It refers to a condition usually seen in young hamsters after weaning or re-homing. Wet-tail and other forms of diarrhea can be fatal and always require urgent veterinary attention. 

Many different types of bacteria can cause gastroenteritis in hamsters. It is not necessary to know them, only to act quickly if you see diarrhea. Your vet may prescribe antibiotics, fluids and probiotics. Stress, re-homing, sudden diet changes and too much fruit or vegetables can bring on diarrhea. 

Always introduce a new food slowly so your hamster’s gut can adjust. The bacterial population in a hamster’s gut adjusts to each diet to perform digestion. Sudden food changes cause digestive upset (diarrhea or bloating) because the bacterial population doesn’t have time to change. 

The time frame for introducing new foods depends on the type of food and age of the hamster. In general, introduce wet food during at least a week in pieces no bigger than pecan size. For young hamsters, offer the new food every other day. You can be a bit less cautious with dry food — changing over to it in about five days.

Gastroenteritis can be infectious, so isolate any affected hamster from other animals as a precaution. Whether a sick hamster might infect another animal depends on the agent causing the gastroenteritis. Of the many bacteria that cause hamster diarrhea, only a very few can infect humans — although it is important to be aware of this possibility.  

Giardia sp.(Back to Top)
Hamsters with diarrhea may be infected with a number of parasites, such as the one-celled protozoan Giardia. While this parasite may be found at low levels in the feces of seemingly healthy hamsters, it is often associated with gastroenteritis. It’s unclear why some hamsters tolerate the parasite and others develop a problem. The parasite may be detected through a direct fecal parasite examination under a microscope. A skilled examiner may detect the characteristic “owl eye” cysts of Giardia species, but this is a crude measure and only detects moderate to high levels of infection. It is a great rapid screening test that can be done by a veterinarian within 15 minutes. A much more sensitive PCR test detects the DNA of Giardia species in a fecal pellet. This test is run by specialized laboratories and may take several days to confirm the infection.

Giardia responds well to albendazole or metronidazole but all affected hamsters must be treated at the same time. Because the protozoan parasite is passed in the feces, hamsters may reinfect themselves as a result of their normal behavior of eating their own feces. It may also pass from hamster to hamster, and cysts in the environment may reinfect a hamster that was already treated.

To combat Giardia in the environment, you must spot clean the cage to remove feces daily and do a thorough cleaning every three to five days during treatment. Dump out all bedding, wash all cage furnishings in warm soapy water, then rinse well. Dilute chlorine bleach should be applied to all cage furnishings and allowed to sit for 15 to 30 minutes before being rinsed well with hot water. Don’t forget to disinfect your hamster’s holding cage and exercise balls or other outside-the-cage toys and play areas.

If the diarrhea is causing dehydration, mucus or blood, the outlook is uncertain. Your hamster may need additional fluids by mouth or by injection beneath the skin, other antibiotics, pain relievers and assist-feeding. The more quickly a hamster with Giardia is diagnosed and treated, the more likely it is to survive.

Glaucoma (Back to Top)
Some dwarf hamsters can develop an eye condition known as glaucoma. The main sign of this is a strong aversion to light and the eyeballs may bulge. 

All mammals can develop glaucoma, but in hamsters it’s more prevalent in dwarfs than Syrians. This condition causes the pressure of fluid inside the eyeball to gradually increase, and eyesight deteriorates as the retina is damaged. Hamsters of any age can develop glaucoma, however, the incidence rises in hamsters older than 1 1/2 years.

Your vet can treat glaucoma with various drugs or eye enucleation (surgical removal of the eyeball). The latter sounds unpleasant but is relatively simple and will not adversely affect the quality of your hamster’s life. If left untreated, glaucoma leads to blindness and severe pain, so veterinary attention is a must. 

Hair Loss, Hair Thinning (alopecia) (Back to Top)

hair loss, hair thinning
Hair loss on hamsters can be symmetrical (shown) or on one spot like the nose.
Click image to enlarge.
Hair thinning and loss is normal in elderly hamsters, particularly on the belly. Hair loss varies, but is often more obvious in females.

If hair loss is severe, sudden and spreading, it may be a hormonal problem. This is usually, but not always, symmetrical. The exposed skin may look normal or pigmented, smooth and thin. Hormonal disorders can be associated with old age and tumors. These are difficult to treat, but may not affect quality or length of life. Slight behavioral changes may occur, which you can discuss with your vet.
Alopecia can be secondary to self-trauma caused by itching. This occurs if a hamster scratches itself enough to cause hair loss.

Hyperadrenocortism (Back to Top)

Head tilt is a neurological sign of illness in hamsters. This hamster is suffering from head tilt and dehydration. 
Click image to enlarge.
A hamster that has hair loss and an enlarged swollen abdomen may have a disorder of its endocrine system known as hyperadrenocortism or Cushing’s disease. In hamsters, this is often caused by a tumor of the pituitary gland, which is found near the center of the brain. This tumor puts out hormones that cause the adrenal glands, which are found in the abdomen near the kidneys, to put out too many hormones, particularly ones called glucocorticosteroids. Some hamsters develop hyperadrenocotism due to a tumor or excessive growth of the adrenal glands themselves.

Over time, overproduction of adrenal hormones cause hair loss, thinning of the skin and thinning of the muscles, as well as increased drinking and a sometimes insatiable hunger. An afflicted hamster may be nearly bald, with only small patches of fuzzy fur on its head and face and paws, and may have an abdomen that is about twice its normal size as a result of stretching of the belly muscles.

One medication, cabergoline, has been effective in extending the lives of rats with pituitary tumors, but its effectiveness in hamsters hasn’t been demonstrated. Trilostane has helped hamsters with adrenal hypertrophy and tumors, but may not help decrease the signs caused by pituitary-based tumors. It may take weeks for a hamster to regrow its fur if the medication is helping.

As the condition worsens, a hamster may develop sores on its skin that don’t heal. It may have trouble walking around, either due to the enlarged abdomen and weak leg muscles, or as a result of brain damage from a growing pituitary tumor. Neurological signs like a head tilt, seizures or exophthalmos indicate a hamster is nearing the end. Euthanasia should be considered when a hamster has any of these serious problems that no longer respond to treatment.

Hypothermia (Back to Top)
Wild hamsters live in burrows that are insulated with thick layers of soil and rock that protect them from excessive heat and cold. Our substitutes are often plastic or cardboard, and the only insulation is from the bedding they pull into their hide boxes. In an unheated winter room that drops below 68 degrees Fahrenheit, a Syrian hamster may be so cold that it starts to shiver. If it can’t find a small insulated area that allows it to warm up, it can quickly develop a life-threatening low body temperature (hypothermia). Once this happens, the hamster falls into a coma. A hypothermic hamster should be slowly warmed back to normal body temperature, such as being cupped in warm hands or wrapped in warm towels right from the dryer that are hot but not too warm to hold.

Prevent hypothermia by providing plenty of thick bedding and a selection of hide boxes of different sizes so your hamster can pick the one that keeps it warm and comfortable. Better yet, keep your hamster in a room that feels comfortable to you, one that is at least 68 degrees Fahrenheit at all times.

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Posted: October 6, 2011, 3:25 p.m. EDT

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Reader Comments
My hámster was bitten on the nose by my other hamster and she is doingnthis weird sound like chittering because she was also bitten near her mouth. Someone please tell me what to do.
Monica, Turlock, CA
Posted: 7/26/2015 8:59:47 AM
My hamsters eye is bright red and bulging! What can I do?
angie, International
Posted: 7/5/2015 10:54:03 PM
Perhaps someone else's pet has the same problem. My 4 month old Syrian has a strong beating coming from his paws. The beats are always in three's and never any less or more. I am suspecting it is just a strong pulse, but I am unsure as to what it is.

If someone knows what is wrong with my hamster, please could somebody let me know?
Kayleigh, International
Posted: 4/14/2015 3:12:50 PM
Please help! Came home today and my hamster was stone cold, shivering almost in coma like state, I wrapped him in a warm sock and put it in my hands, etc, he revived some and drank some water, but still seems really listless, just laying about in his tubes, is there anything else I can/should do??
Faith, Omaha, NE
Posted: 3/3/2015 4:38:42 PM
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