Hair loss in cats. Over-grooming resulting in alopecia.
Cats spend a large chunk of their daily life grooming. This is part of their daily hygiene to keep themselves clean and to remove any loose hair. It is therefore sometimes difficult to recognize that your cat is over-grooming itself. Many people only discover that something is wrong when they notice bald patches on their cat's skin. This hair loss is a condition known in medical terms as alopecia. In some cats alopecia is hereditary, a typical example being the sphinx.
However, in most cases hair loss is secondary to another disease process. There are a number of possible causes ranging from serious (e.g. Cushing's disease) to less severe (e.g. allergies). If the hair loss is localized to a particular area or areas this may be indicative of over-grooming. Over-grooming is often a stress related disorder which is classified as obsessive compulsive behaviour, similar to but more severe than a human pulling at his or her hair. But this is not always so, indeed skin infection, parasites or local injury must be considered first. The vet will be able to check for skin infections by taking skin scrapings from the bald area or with a blood test. If a skin infection is diagnosed, eradication of the infectious agent should sort out the problem. If food allergy is suspected the vet will suggest a change of diet. Making the right diagnosis is important because the treatment in each case will be different.
Note also that some cats have naturally thinning hair, sometimes on the top of their head, or at points on their faces which they frequently rub against objects which they want to mark with their scent. This is particularly noticeable with short-haired black cats that have pink skins, but is not a problem unless total baldness results in these areas. With long-haired cats matting of the fur (caused, for example by a condition called studtail) means that a cat can develop a temporary bald patch where the mat has been removed. If the underlying condition has been treated and the skin beneath is healthy, lost hair usually grows back again.
If there is no underlying medical condition, completely bald patches on a cat's pelt are likely to be self-inflicted due to over-grooming resulting from stress. Over-grooming may start at any time and is often triggered by changes in cat's environment. Cats are very much creatures of habit. So any changes to their lifestyle will be stressful. Some of the major stresses in a cat's life are: moving to a home; a new addition to the household, be it a new baby, new dog or new cat; or on the other hand the loss of member of the family, which again that could be the death of a cat in the multicat family, or the death of the cat's human. A cat that has had a serious illness or trauma might also react by shedding hair in dramatic quantities as though moulting out of season (sometimes called 'blowing her coat'), and this can result in overall thinning of the pelt and also bald patches.
Some cats adjust quickly to new changes, or indeed even seem to welcome them, but for others it takes months to come to terms with a new situation. Grooming may then become a stress displacement activity. Many cats under emotional pressure will resort to grooming, an activity which cats find calming and soothing. This escalates into a problem when grooming becomes compulsive, because this habit will persist even when the original stress factor is removed. Compulsive grooming is difficult to treat. But the most important thing is to reduce stress to a minimumal level. Stick to a routine which changes as little as possible. Remember that it is not just big things which can be stressful. Things which appear small to us, such as transferring a cat scratcher from one room to the next, might be a seriously major issue for a cat.
The next thing is to introduce new activities and increase the cat's play time. A busy cat will have less time for grooming. Provide a distraction every time you see the cat grooming her bald patch. If it is not possible to get her grooming under control by reducing stress and enriching her environment, it may be necessary to introduce anti-anxiety medication. Make sure you consult with the vet about appropriate medicine and dosage. Never use human anti-depressant drugs or another cat's medicine. Once the over-gooming comes under control, the medication can be gradually tailed off. Remember never to stop medicine rapidly.
Note: This information is for guidance only. It is not intended to replace consultation with a licensed practitioner.