The most common causes of severe pelvic fractures in cats are hit-by-car accidents, falls, and blunt trauma. In general, with proper care the prognosis for cats with pelvic fractures is good. However, permanent lameness, neurologic damage, incontinence, and dystocia in breeding queens do occur and clients must be warned of these complications. Recently, 3 cats with permanent alopecia on the lower back after pelvic fractures were described. Skin biopsy specimens from the areas showed similar findings: follicular and adnexal atrophy, follicular telogenization, fibrosis in the dermis, and inflammation of the panniculus. All of the cats presented with acute hair loss 3 to 4 weeks after injury, and the skin had a glistening appearance. Although the exact pathogenesis is unknown, the authors speculate that the hair loss was secondary to external trauma to blood vessels supplying the skin over the area and subsequent ischemia.

COMMENTARY: Most owners of cats that have survived a traumatic incident serious enough to cause a pelvic fracture are usually relieved if the cat recovers without permanent neurologic injuries (e.g., paralysis or incontinence). Although it may seem trivial compared with other possible permanent complications, veterinarians should warn clients that focal permanent hair loss may also be a complication. From a broader perspective, posttraumatic alopecia should be included in the differential diagnosis of cats presenting with acute hair loss on the lower back.

Alopecia and dermatopathy of the lower back following fractures in three cats. Declercq J. VET DERM 15:42-46, 2004.