Common Hamster Illnesses: Causes, Symptoms & Treatment

Hamsters are lovely, tiny pets popular with children due to their adorable miniature sizes. While these pets are beautiful, being small in size means even a minor injury or illness can turn fatal. You need to be on the lookout for common hamster illnesses to ensure your lovely hammy is healthy.
In this article, we will take a deep dive to highlight the diseases and infections hamsters are prone to, what you need to look out for, and how you can help your pet. We will also link to guides that focus on each illness in depth.

Common illnesses in hamsters
The most common hamster illnesses include ringworm, wet tail, pyometra, pink eye, skin abscess, diarrhea, colds, and constipation. Most of these common ailments can be treated and/or are manageable.
1. Ringworm
Ringworm is a fungal infection that affects a hamster’s skin forming bald circular or ring-like patches (hence the name). The patches may have dry, crusty, flaky skin and the hamster will oftentimes scratch at them.
Ringworm in hamsters is mainly caused by Trichophyton mentagrophytes and Microsporum fungi species. Infection happens through contact with infected animals or humans or contaminated items such as bedding.
Your veterinarian can conduct a physical examination or laboratory tests to diagnose the infection. Ringworm is a treatable infection and treatment includes topical and/or oral antifungal medication.
It’s important to keep in mind that ringworm is one of the hamster diseases contagious to humans. Always wash your hands thoroughly with soap and clean running water after contact with your pet.
You should also use protective gear such as disposable gloves when cleaning your hamster’s cage or handling its contents such as bedding, bowls, and toys.
2. Wet tail
Proliferative ileitis, commonly known as wet tail, is a highly contagious hamster illness caused by bacterial infection and stress-enhancing factors such as sudden dietary and habitat changes, extreme temperatures, unsanitary living conditions, poor diet, and overcrowding in the cage.
The infection can be fatal and is common among young hamsters aged between three to 10 weeks as well as recently weaned baby hamsters. A hamster with a wet tail can die in a matter of days if it does not get immediate veterinary care.
Hamsters with wet tail should be separated from the others to curb the spread of the disease. Note that the incubation period for the infection is about 7 days, which means a seemingly healthy hamster might already be infected.
Notable signs of wet tail in hamsters include:
- Loss of appetite
- Lethargy
- Ruffled coat
- Wet tail due to watery diarrhea
- Possibly a smelly bottom
- Matted or sweaty look
- Dehydration
It’s important to note that not all hamsters with excessive diarrhea have wet tail. However, you need to seek veterinary care for your hammy if you notice any of the symptoms above.
Treatment of wet tail includes the use of antibiotics, fluid therapy for rehydration, and providing the hamster with enough nourishment.
3. Tyzzer’s disease
Tyzzer’s disease is a highly contagious disease caused by the bacterium Clostridium piliforme. The disease is common in young and stressed hamsters and often bears symptoms similar to wet tail (proliferative ileitis) such as loss of appetite, watery diarrhea, and severe dehydration.
The infection occurs when a hamster ingests feces containing the bacteria, which affects the digestive system causing watery diarrhea and severe abdominal pain. In all animals, hamsters included, the infection is characterized clinically by liver failure and icterus.
Diagnosis for Tyzzer’s disease can be confirmed by histopathologic analysis and PCR assay of C piliforme. Treatment options include the use of fluids and antibiotics.
Since the infection is contagious, infected hamsters and those they came in contact with should be kept in isolation to prevent the spread of the disease. You should also thoroughly clean and sanitize the cage, food containers, and water bowls used by the infected hamsters.
4. Pyometra
Pyometra is a uterine infection that mainly affects older female hamsters and is characterized by an accumulation and/or discharge of pus or blood from the uterus. The condition can be caused by structural and hormonal changes in the uterine line leading to infections.
The condition can also be caused by bacteria such as Escherichia coli and streptococcus or a virus such as Lymphocytic choriomeningitis. Stump pyometra occurs when uterine tissue left inside the uterus after spay surgery causes an infection.
There are two main types of pyometra; open and closed. Open pyometra is characterized by the discharge of blood or pus from the vulva. In closed pyometra, however, the cervix is closed and the lack of an outlet means the pus or blood will accumulate inside the uterus causing abdominal swelling or bulge.
Symptoms of pyometra largely depend on whether it is closed, open, or stump. Vulva discharge of pus or blood can indicate the presence of open pyometra while a distended abdomen can indicate closed pyometra.
Treatments for pyometra in hamsters include surgery, antibiotics, and palliative management.
5. Pink eye
Pink eye, also called conjunctivitis, is an inflammation of the conjunctiva resulting from infection, injury, or irritation. The conjunctiva is the clear membrane covering the white part of the eye and lines the inside of the eyelid.
The term pink eye is from the red/pinkish appearance of the eye resulting from the blood vessels becoming more visible as a result of the inflammation. Symptoms of pink eye in hamsters include:
- Red, pink, or bloodshot eyes
- Clear, white, yellow, or green discharge from the eyes
- Squinting or rubbing of the eyes
The primary causes of pink eye include bacteria, viruses, fungi, allergies, and irritants. Bacteria and viruses can spread through the air, contaminated food & water, or contact with an infected hamster.
Fungi are common in damp, dark areas while allergens may include dust, pollen, or chemicals. Irritants that can cause pink eye in hamsters include dust, wind, and bright light.
Treatment for the infection depends on the cause. Bacterial infections require antibiotics, which could be in the form of eye drops or ointment while corticosteroids will be prescribed to treat an infection caused by allergies. Your vet will recommend the use of fungicide if a fungus is the cause of the infection.
6. Skin abscess
Skin abscesses are pockets of infected pus under the skin caused by bacterial infection of wounds. When the wounds get infected, pus starts to accumulate under the skin and can form a sizable lump.
Abscesses can also form in the cheek pouches when abrasive food materials cause scratches or injuries in the inner lining of the mouth. Your hamster could be having an abscess if it always looks like it has food packed in its cheek pouches.
The injuries and wounds that pave way for skin abscesses to develop are mainly from cage fighters and sharp objects in the cage.
Treatments vary depending on the condition of the infection, but often your veterinarian will drain the abscess and administer an antibiotic. A surgical procedure can also be performed in some cases.
In case the flank glands are infected, the vet will probably shave the area around them, clean it, then apply an ointment containing antibiotics and steroids.
To prevent abscesses in hamsters, make sure there are no sharp objects in your hammy’s cage and separate hamsters that constantly fight. You should also ensure the food your hamsters eat is non-abrasive.
7. Tumors & cancers
Hamsters can also suffer from tumors and cancers. The tumors can be benign or malignant. Genetic and environmental factors play a key role in the development of the disease.
Although most tumors in hamsters are not cancerous, they can develop in certain parts such as the adrenal gland, which can lead to other health complications. Malignant tumors are common in older hamsters and can metastasize to other parts of the body.
Lymphoma (cancer of the lymph nodes) can occur in older hamsters. Tumors grow in the lymph nodes and other parts such as the liver, spleen, and thymus. There is also a T-cell lymphoma that affects the skin causing patchy hair loss, skin inflammation, lethargy, and weight loss.
Apart from the lymph nodes and adrenal glands, tumors in hamsters can also develop in the mammary glands, uterus, intestines, eyes, brain, and skin.
Some tumors can be removed through surgery while others can prove difficult, making it impossible or risky to perform the procedure. In such cases, your veterinarian may recommend palliative treatments.
8. Diarrhea
Diarrhea is one of the most common digestive complications hamsters experience. The hamster’s stool will be overly soft or liquid and its bottom will be very dirty. Read this article if you do not know what hamster poop looks like.
The most common cause of diarrhea in hamsters is overfeeding of vegetables and fresh fruits. Other causes include bacterial infections, dietary changes, intestinal parasites, treatment with antibiotics, and poor hygiene.
Diarrhea can be mistaken for wet tail; common symptoms include dehydration and a wet & possibly smelly bottom. However, a hamster suffering from diarrhea (and not wet tail) will still be very active and will not show any signs of loss of appetite.
You should discontinue feeding your hamster vegetables and fruits for a day or two while making sure your pet is drinking more water to counter dehydration. Seek veterinary care in case the condition persists.
9. Colds
Colds are common in hamsters and are often exacerbated by exposure to cold temperatures. Common symptoms of colds in hamsters include:
- Reduced activity
- Swollen, runny nose
- Ruffled fur
- Sniffing & sneezing
- Watery eyes
- Redness around the nose
You should disinfect the cage and all the watering and feeding bowls. Make sure to also provide fresh, dry bedding and keep the cage free from drafts. Your hamster can also do with sufficient wholesome foods.
10. Constipation
Constipation is a common health problem hamsters go through. The condition may be caused by intestinal parasites. It can also happen when a hamster eats its bedding and the intestines get blocked or if a part of the intestines folds itself, a condition called intussusception.
Intussusception may be caused by poor diet, intestinal inflammation, and not drinking enough water. In severe cases, this condition may cause rectal prolapse, a medical condition that can cause death if you do not seek immediate veterinary help for your hamster.
Common signs of constipation in hamsters include a lack of excrement in the hamster’s cage, swollen anus, and swelling of the belly due to the accumulation of digested food.
If the cause is diet-related, appropriate treatment is the use of a laxative or fruit and vegetables with the same effect. However, your vet will recommend surgical treatment if intussusception is the cause.
11. Exophthalmia
Eye bulging, medically called exophthalmia, is a condition where the hamster’s eyeballs protrude from the eye sockets. It can be caused by corneal injury, eye infection, abscess behind the eye, allergies, dental disease, glaucoma, and trauma.
Although it’s common for hamsters to experience the bulging of eyeballs, exophthalmia is often a sign of an underlying condition and you should seek veterinary care for your pet as soon as you notice any of the symptoms.
Symptoms of exophthalmia in hamsters include swelling of the eye, discharge in the eyes, crusting around the eyes, pawing at the face, and color change of the eye.
Treatment options include antibiotics, pain medications, and topical ointments. A corrective dental procedure can also be performed if the cause is dental abnormalities. Severe cases may call for the removal of the eye.
12. Amyloidosis
Amyloidosis is a condition in which the hamster’s body produces amyloid, a dense protein, which accumulates in various organs including the kidneys and liver. Continued accumulation affects the normal functioning of these organs.
Amyloidosis is more prevalent in females and mainly affects hamsters with long-term illnesses and those aged one year and above.
Unfortunately, hamsters with this condition do not show any symptoms of the disease until the kidneys stop working as a result of excessive amyloid deposits.
As a result of kidney failure, chemicals build up in the blood leading to the accumulation of fluid in the body, depression, and inevitably death. Hamsters with amyloidosis show symptoms such as rough hair coat, hunched posture, and loss of appetite.
To diagnose the disease, your veterinarian will conduct blood and urine tests. The results will show the presence of high amounts of protein in the urine, high levels of proteins globulin and albumin, and increased levels of cholesterol.
Unfortunately, amyloidosis has no treatment. The best you can do is make your hamster as comfortable as possible.
13. Pseudotuberculosis
Pseudotuberculosis is a bacterial infection caused by exposure to the bacterium Yersinia pseudotuberculosis. Exposure mainly happens when hamsters eat food or drink water that has been contaminated with the feces of wild birds or rodents.
The disease can cause health problems such as blood infection, extreme weight loss, and diarrhea. Severe effects include degeneration of the lymph nodes, lungs, liver, spleen, gallbladder, and intestinal walls.
The disease has no treatment and is contagious to humans. This means any hamster with the disease should not come into contact with humans and must be euthanized.
If your hamster is infected with the disease, make sure to thoroughly clean and sanitize its cage and be sure to wear gloves when doing the cleaning or disposing of contaminated materials.
14. Mange
Mange is a common health problem in hamsters defined by grey, warty scabs on the nose, ears, and genitals. It can be caused by parasitic spiders or insects.
You can tell your hamster has it if it constantly scratches its ears, shakes its head more than usual, is losing its hair, and has a poor general appearance.
Your veterinarian will recommend a medicated bath for your hamster and sterilizing its cage and all the items such as toys. You should also replace the bedding after cleaning the cage.
Final thoughts
There are many illnesses that affect hamsters. Most are treatable and manageable while a few may sadly necessitate euthanizing your lovely hammy. We recommend seeking immediate veterinary care for your hamster in case you suspect it’s suffering from any of these ailments.