Common Hamster Illnesses

by Hamster Care

Common hamster illnesses


  • Seek a vet’s advice asap when your hamster is unwell
  • Observe your hamster’s behaviour
  • Keep your hamster’s environment clean

Note: This article is just to give parents a general idea of the common illnesses hamsters are susceptible to and the corresponding prognoses. This article is not intended as a “self-help” guide in any way, so please always seek a professional vet’s advice as soon as your hamster shows any symptoms or signs of illness.

Wet tail (proliferative ileitis)

Wet tail is a condition caused by Lawsonia intracellularis, a type of bacteria which inflames the small intestine and subsequently causes diarrhoea. Although it is quite contagious, it generally affects only young Syrian hamsters.

A hamster with wet tail will show signs of lethargy, diarrhoea (look out for wet fur and a foul smell) and, ultimately, weight loss. However, not every case of diarrhoea in hamsters is caused by wet tail.

Wet tail is lethal and your hamster could die if not treated immediately, so always seek medical attention as soon as possible. Oral medication and antibiotics are the normal course of treatment for wet tail.

Yeast Infection/fungal Infection

This is a very common illness among pet hamsters in Singapore due to our hot and humid climate, which promotes the rapid growth of all sorts of fungi. It occurs when the fungus Trichophyton mentagrophytes, typically present in contaminated beddings, infects your hamster in a number of places. Thankfully, it is not lethal, and given the right care, can be cured in as little as two weeks. However, please note that it is contagious, so prevention is always better than cure!

To diagnose a yeast/fungal infection, a sticky tape cytology is normally used. Treatment consists of oral administration of antifungal (griseofulvin) medication.


Pyometra is a life-threatening condition caused by an infection of the uterus/womb, typically affecting older female hamsters. So far, hamsters have been observed to be prone to two main types of pyometra – open and closed.

An open pyometra can be identified by the discharge of blood or pus from the vulva area of the hamster. The discharge is able to ooze out when the hamster’s cervix is open, which is a good thing, because the infection can be drained from the hamster’s body. Please note that hamsters do not menstruate, therefore, any bloody discharge from the vaginal area should be reported to your vet as soon as possible.

A closed pyometra is much more serious. When the cervix is closed, the blood and pus accumulate within the body, eventually causing the abdomen to bulge.  Due to the lack of noticeable discharge exiting the body from the vulva, a closed pyometra usually only gets detected in the later stages, when the abdomen begins to noticeably protrude. With the pressure building internally, bacteria and toxins may also start to spread across the uterine walls, ultimately resulting in blood poisoning.

A useful thing to watch out for is fast-emptying water bowls, as hamsters with pyometra tend to consume much more fluids than usual. When it comes to treatment, the surgical removal of the uterus (spaying) is one way of treating or preventing pyometra. However, with hamsters, all surgical procedures carry a high degree of risk due to their relatively small size, so operations are often a last resort.

Urinary tract infection (UTI)

UTIs are another fairly common disease among hamsters, due to their small size and the ease with which bacteria can enter the urethra and infect the bladder. A hamster with UTI will urinate with great frequency, and often with traces of blood in their pee. To confirm the diagnosis, a urinalysis is usually carried out.

UTIs tend to be a painful experience for the infected hamster. Its body will attempt to flush out the infection by taking in more liquids, so it is important to keep your hamster as hydrated as possible. However, please note that UTIs rarely dissipate naturally, and can quickly escalate to a kidney infection. Please procure oral medications such as Enrofloxacin (Baytril) from your vet early on to ensure that the UTI is properly cured before it can develop into something worse.

Chronic kidney/renal disease (CKD/CRD)

Just like with humans, your hamster’s kidneys are responsible for flushing toxins from its body, and sometimes, just like human kidneys, they malfunction, resulting in a dangerous build-up of toxins in the body. This condition is usually diagnosed with blood and urine samples.

A hamster with renal/kidney disease will show signs of frequent urination, and increased lethargy accompanied by weight loss. When diagnosed, in addition to oral medication, your hamster will need to be put on a special diet, usually featuring foods that are lower in protein, sodium and phosphorus.  


Pneumonia is a bacterial inflammation of the lungs. Common symptoms include wheezing, coughing, sneezing, mucosal discharge from the nose or eyes and a lethargic appearance. Loss of appetite may also occur. Pneumonia is potentially lethal to hamsters and can be contagious.  

To treat pneumonia, antibiotics are usually prescribed, and in serious cases, the hamster may be hospitalised and placed on oxygen therapy.


Sometimes, odd lumps/masses can form on your hamster’s body, which are typically caused by either tumours (benign/malignant) or infections (abscess). If you spot one, be sure to monitor the growth of the lump/mass.

Most small lumps/benign tumours will not affect your hamsters’ life, so if the lump/mass does not show signs of growing, surgery may thankfully not be necessary. It is best to avoid surgery where possible as, due to their small size, hamsters cannot be placed under anaesthesia for long periods. That is why surgery for hamsters carries with it a much higher risk than for other, larger pets. However, tumours that get bigger over time are most likely malignant and cancerous. In such cases, surgery will be required to remove the tumour, and the sooner it is removed, the better.

Sometimes, especially in dwarf hamsters, ear warts can occur. If you notice the wart growing larger over time, contact your vet as soon as possible, as it is best to remove growing warts while they are still small. Be warned that, due to the high surgical risks explained above, some vets may not agree with surgically removing ear warts, especially if your hamster does not appear to be adversely affected by them.

In cases where the warts are non-threatening, oral medications such as Enrofloxacin (Baytril) and Meloxicam will be prescribed. Topical medications may also be provided to disinfect any wounds.

Bumblefoot (Ulcerative Pododermatitis)

This is a bacterial infection and inflammatory reaction of the feet. It is typically caused by poor husbandry practices, such as using a meshed surface or a meshed wheel, so, please always provide an appropriate wheel for your hamster! Poor sanitation leading to bacterial build-up can also cause bumblefoot. Other causes include overgrown toenails and obesity.

To spot bumblefoot, look for signs of swollen feet and lameness. A hamster with bumblefoot will be reluctant to move around due to the pain in their feet. Although bumblefoot is usually not difficult to treat, complications such as infections can occur if not diagnosed and treated early.  

Both oral and topical medication are used in the treatment of bumblefoot.

Eye infection

Eye infections are generally an uncommon occurrence, but if your hamster does come down with an eye infection, it will most like be due to a dusty environment, or the presence of other allergenic particles, like bath sand, that trigger your hamster’s immune response. Eye infections are not lethal but can cause highly unpleasant symptoms such as balding, red and irritated eyes, and in extreme cases, even tears around the eye.

If you suspect your hamster has an eye infection, please bring them to the vet for antibiotics as soon as possible. The antibiotics may be orally or topically administered, or both.

Caring for a sick hamster

Immediate isolation

If your hamsters currently live in pairs/groups, it is important to place the sick ones in quarantine. Particularly in the case of contagious illnesses, quarantining the infected hamster will prevent the spread of the disease and keep your other hamsters healthy (and your vet bill small).

Note: Hamster Society (Singapore) strongly encourages housing all hamsters individually.

Keep the environment as pristine as possible

Bacterias dislike clean environments. So, keep your hamster cage spick and span at all times to keep bacteria, and the illnesses caused by them, at bay.

If necessary, temporarily swap your regular bedding for kitchen towels. In cases like yeast infections, this helps to prevent additional contamination of the cage and helps to contain the spread of infection. Lay the kitchen towels flat in the cage without shredding them, and change them daily or as soon as they are soiled.

Cleanliness is next to godliness, and coincidentally, is also extremely vital to your hamster’s recovery. Be sure to keep your hands clean at all times when handling your hamster or your hamster’s cage.

Regularly observe your hamster

In order to provide your vet with a better picture of your hamster’s progress, try to note down your hamster’s behaviour. Is it active or lethargic? How are the appetitive levels? What is the frequency of the bowel movements? This will help tremendously in the follow-up appointment with the vet, who will consequently be able to provide better medical care for your hamster.

Please also keep a keen eye out for any unusual or ominous signs, such as breathlessness and bleeding. If your hamster shows these symptoms, contact your vet immediately for advice, and be prepared to bring your hamster to the vet for an emergency.

Follow your vet’s instructions

Administer all medications as per your vet’s instructions, whether oral or topical. If regular wound cleaning with a saline wash is required, be sure to adhere to the cleaning schedule as strictly as possible, even if you may have to get help from family members to do so.

If you want more helpful advice on looking after your hamster, including tips on toys, accessories and accommodation, add a comment below to let us know!

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By HamsterCareTip.Com

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