Common Rat Health Problems

Get the basics on the common health issues rats may experience.

Written by
Ailments common for rats include overgrown teeth, abscesses and conjunctivitis. gallinago_media/iStock/Thinkstock
Audrey Pavia

Conjunctivitis And Corneal Ulcers

Rats can develop irritation to the eye as a result of poor cage hygiene or getting a piece of bedding in the eye. The irritation might be mild and temporary or it may result from a more serious corneal ulcer. If you see tearing, redness or swelling in your rat’s eye, take it to a veterinarian immediately.

Red Tears

Red or black discharge around the eyes and nose is very common in rats. An organ called the harderian gland, located behind the eyeball, may ooze a red secretion that lubricates the eye and eyelid.  This secretion sometimes gives the appearance of blood but contains none and is normal in small quantities. If the tearing becomes excessive, your rat might have a respiratory infection and needs to visit a vet.

Hair Loss

If your rat experiences hair loss due to stress, the hair comes out in patches without itching or redness. Fleas, on the other hand can cause itching and subsequent hair loss, as can allergies to bedding. A poor or low-protein diet can lead to hair loss as well. If your rat is losing its hair, take it to the veterinarian for a diagnosis.

Overgrown Teeth

Rats teeth grow continuously, so they must gnaw to keep them short. If rats are not given chew toys to gnaw on, their teeth can grow so long they will curve around and injure the rat’s mouth. A condition called malocclusion, where the teeth are not properly aligned and don’t wear down naturally, can also cause dangerous overgrowth. Rats with malocclusion must have their teeth regularly trimmed by a veterinarian.

Increased Urination

Rats are prone to kidney disease, which can cause increased urination. This usually occurs in older rats or rats given too much sugar or salt in their diet. If you notice increased urination in your rat, talk to your vet about lowering the amount of protein in your pet’s diet.

Head Tilt

Rats suffering from an inner ear or respiratory infection can develop a chronic head tilt. A stroke or a pituitary tumor can also cause the same symptom. If your rat has a head tilt, and/or loses his balance frequently, take it to the vet immediately.

Swelling Under Jaw

Injury to the mouth, an abscessed tooth or swollen lymph nodes can cause swelling under the jaw. If you notice a puffy appearance on the lower part of your rat’s face, contact your veterinarian right away.


When a rat suffers an injury that punctures the skin, an abscess may form. Abscesses often show up as swollen masses in the area of the injury and will grow as the infection progresses. Abscesses must be treated by a veterinarian.

Article Categories:
Critters · Mice and Rats