If you notice a patch of missing hair on your cat this can be worrying. Hair loss (alopecia) can have many causes and always warrants investigation by your vet.
Hair loss can be the result of skin infections such as ringworm (not a worm but a fungal infection), infestations with parasites such as mites, and is often self-inflicted as a cat over-grooms an itchy area caused by an allergy or a flea infestation. Over-grooming may also result in a problem with vomiting fur-balls as the cat swallows the removed fur. Occasionally a stressed cat can start to pull out fur and, in unusual cases, may over-groom a painful area, for example a sore joint or their tummy if they suffer pain in their bladder. Unusual hormonal problems can also cause hair loss. Some causes of hair loss are transmissible to humans, although this is unusual, so this is definitely not a time to delay that visit to the vet!
General poor health, nutrition or underlying disease can make the coat lose shine and possibly also result in hair loss.
Investigation
Your vet will need to look for the cause of the alopecia. As fleas are a common cause of itching and resulting hair loss, your vet may recommend a flea treatment (which it is advisable to keep up to date anyway). Your vet may also take samples of hair or painlessly scrape a little sample of skin to test for ringworm and parasites, or take blood samples to look for underlying diseases. If you or your vet suspect a behavioural problem is causing the over-grooming and resulting hair loss, then you may need to examine your cat’s lifestyle for sources of stress. Occasionally a small skin sample will be taken under anaesthetic or an allergy skin test performed. Consultation with a veterinary dermatologist is recommended if the cause for the alopecia is unclear.
Treatment
The treatment for alopecia obviously depends on the underlying cause. It is important to pursue investigations to ensure correct treatment. Flea control is always recommended for all cats and your vet may recommend other treatments if another cause is identified (e.g. anti-fungal treatment for ringworm). Treatment of allergic skin disease can be challenging and taking advice from a veterinary dermatologist is advised
If stress-related over-grooming is suspected, referral to a veterinary behaviourist may help identify the cause of the stress and provide advice on methods to reduce it. If painful joints or bladder are resulting in over-grooming, then treatment of the underlying problem or pain-killing medication may be prescribed by your vet.