The most common reason a cat will overgroom is fleas. If treated effectively, most cats will cease the behaviour within a matter of weeks. Other underlying causes include food allergies, boredom, skin irritation, parasites, infections or constipation. In order to accurately diagnose and treat your cat, your vet will usually conduct diagnostic tests on the blood and skin, as well as trial medication and/or diet.
If your vet is unable to find an underlying medical/ environmental cause, your cat may be diagnosed with psychogenic alopecia – a compulsive disorder usually brought on by stress or anxiety. As cats find self-grooming extremely comforting, if they are confronted with sudden conflict, a change in environment or a perceived threat, they often groom themselves to feel calm. In most instances, the behaviour will cease once the threat has disappeared. However, if the cat continues to lick and groom compulsively, even once the threat has gone, it is likely that the behaviour has become compulsive and difficult for your cat to control. While psychological alopecia is not life-threatening, it may be symptomatic of an overly stressed or anxious animal, so it’s important to seek effective treatment.