Treatment of alopecia X with medroxyprogesterone acetate.

Background: Alopecia X is a common cause of noninflammatory alopecia in Pomeranian dogs. In the past, treatment with growth hormone injections resulted in hair regrowth in many individuals. Progesterone can induce mammary-derived growth hormone and is used to treat dogs with congenital growth hormone deficiency.

Hypothesis/objectives: To determine whether progesterone induces endogenous insulin-like growth factor-1 (IGF-1) and causes hair regrowth in dogs with alopecia X.

Animals: Eight neutered Pomeranian dogs with alopecia X for 1-2 years.

Methods: In part 1, two male and three female dogs received 5 mg/kg medroxyprogesterone acetate injected subcutaneously (s.c.) every 4 weeks for a total of four injections. In part 2, one male and two female dogs received 10 mg/kg medroxyprogesterone acetate injected s.c. every 4 weeks for four injections. Dogs were monitored monthly with physical examinations and complete blood counts, chemistry panels and urinalyses. In part 3, two coated Pomeranian dogs and two normal-coated small breed dogs received two s.c. injections of 10 mg/kg medroxyprogesterone acetate. Serum was saved from each visit for IGF-1 analysis.

Results: In part 1, two dogs had partial hair regrowth of ~40-60%. In part 2, one dog had partial hair regrowth and one dog had complete hair regrowth 2 months after completion of the study. Unlike the normal-coated dogs, whose IGF-1 concentrations increased, the IGF-1 concentrations in alopecic and coated Pomeranian dogs were low and remained unchanged. No adverse effects were noted.

Conclusions And Clinical Importance: Results of this study showed that medroxyprogesterone injections resulted in partial hair regrowth in three and complete hair regrowth in one of eight Pomeranian dogs with alopecia X.