Hair loss in pet rats has a variety of causes. While certain clues can tip you off about what's going on -- including how many rats are affected, whether the hair is thinning or coming out in clumps, whether there are accompanying symptoms and behaviors you may observe -- your vet should make the diagnosis. This ensures you find out what's really going on and take the proper course of action for treatment.
"Barbering" is the most common cause of hair loss in rats. This is when a dominant rat chews the hair off submissive rats. This grooming behavior isn't usually harmful, as the dominant rat chews the hair down low, but does not make contact with the skin; rarely, though, the behavior is too aggressive and breaks the barbered rat's skin. This generally leaves bald patches on the face, head, neck or shoulders. Occasionally, rats self-barber, chewing off their own hair. This typically leaves hairless patches on the stomach or front legs. Boredom is usually the cause of barbering and self-barbering, so provide your pet rats with additional toys, tubes, an exercise wheel and more time in a playpen or other secure area out of the cage. Offering the submissive rats more places to hide can help, and sometimes you need to separate the dominant barbering rat from the others for a while. Treat rats injured by barbering according to your vet's recommendations, which may include a dressing or a topical antibiotic.
Pet rats who don't get all the nutrients they require through a healthy, balanced diet are prone to hair loss. The bulk of your rat's diet should consist of pelleted rat food, commonly known as lab block because it's what is fed to laboratory mice and rats. Rodent mixtures with seeds, nuts, cracked corn and other non-pellet items are an inappropriate choice for rats, as they fill up on the often high-calorie ingredients that don't supply enough nutrient value. This leads to weight gain and malnutrition. An excess of protein in your rat's diet can also contribute to hair loss. Also, refrain from feeding your rats non-nutritious snacks frequently, and never offer them before the rats have eaten their pellets. Supplement their diet with occasional pieces of appropriate fresh fruit and vegetables for extra sources of essential vitamins and minerals.
Pet rats are prone to lice and mite infestations, though it's rare that the two coexist simultaneously. These skin parasites easily lead to hair loss. Mites are microscopic and burrow under the skin, while lice are visible to the eye and live on their host's body. Their eggs are also visible as tiny beads on hair shafts, as are collections of their feces, known as "flea dirt." Their irritating presence causes rats to scratch excessively, which is one contributing factor to hair loss. These parasites also cause scabbing that prompts hair loss. In fact, scabs and scratching are two telling signs that parasites are your problem. Your vet can diagnose lice on sight, but confirming mites requires a skin scrape to find them. The prescription parasiticide ivermectin is the standard treatment for mites and lice, though lime sulfur dips and other products are also used. Your vet will recommend the best course of treatment.
A variety of skin conditions cause hair loss themselves or are itchy enough to prompt excessive scratching that causes hair loss. Infections are one example, especially fungal infections like ringworm. Manage these with a topical or oral anti-infective medicine; your vet must diagnose the problem to prescribe an appropriate product. Severe dry skin -- often a side effect of malnutrition -- may also prompt scratching. Your vet will look for a cause and recommend a moisturizer or other remedy. Food allergies and contact dermatitis are other possible explanations for your pet rat's hair loss. Peanuts and dairy products are the two most common allergens in rats. Your vet may recommend an exclusion diet to get to the bottom of suspected allergies or an oral or topical medication to control skin symptoms. Stress is another potential culprit. Pet rats may become stressed by environmental changes, bullying, malnutrition, boredom or lack of exercise. Supply and rotate toys and tunnels, feed your rats appropriately and watch for signs of problems between individual rats, which may require separation.
Eric Mohrman has been a freelance writer since 2007, focusing on travel, food and lifestyle stories. His creative writing is also widely published. He lives in Orlando, Florida.