Aloha! You're speaking with Dr. Michael Salkin
I'm sorry that your question wasn't answered in a timely manner. The distribution of Brightee's alopecia is pathognomonic (particularly indicative) for psychogenic alopecia in cats. Feline psychogenic alopecia is overdiagnosed but does exist. Excessive and out-of-context grooming is thought to be an obsessive-compulsive behavior that's triggered by environmental stresses and anxiety. The condition is uncommon in cats, with purebred cats that have high-strung nervous temperaments being possibly predisposed.
Alopecia may occur anywhere on the body where the cat can lick but it most commonly involves the medial forelegs, inner thighs, perineum, and ventral abdomen. Hair loss is often bilaterally symmetrical but remaining hairs don't epilate easily. The top differentials are flea allergy dermatitis, food
allergy, dermatophytosis (fungal infection), other ectoparasites (mange) and atopy (allergies to environmental allergens such as pollens, molds, dust, and dust mites, etc.).
The underlying cause of the psychological stress (e.g., separation from owner, moved to a new house, animal companion died, new pet in household, formerly outdoor cat denied access to outdoors) must be identified and appropriate environmental modifications made, if possible. A good flea control program should be instituted to prevent fleas from aggravating the symptoms. Use of a mechanical barrier (e.g. Elizabethan collar, T-shirt) for 1-2 months to prevent grooming may help break the habit. Behavior-modifying drugs may help stop the abnormal grooming behavior. In some cases, treatment may be discontinued after 30-60 days of therapy; in others, lifelong therapy is required for control. Drugs that may be effective include the following: amitriptyline, clomipramine, buspirone, phenobarbital, diazepam, and naloxone.
I'm concerned, however, that there's a concomitant disorder that has arisen at this time. His eyes at "half-mast" and vocalization (a pain response?) concern me for more than psychogenic alopecia. Those are important symptoms at his age but don't identify the specific underlying disorder and so I must encourage your having Brightee attended to by his vet at your earliest convenience. I can't "watchful wait" a cat of his age for longer than 24 hours. He doesn't have the reserve of a much younger cat.
Please respond with further questions or concerns if you wish.