Estrogen Receptor Antagonist and Hair Regrowth in Dogs with Hair Cycle Arrest (Alopecia X)

In a study conducted 17 years ago, researchers investigated the effect of fulvestrant, an oestrogen receptor antagonist, on hair regrowth in 11 Pomeranian dogs with hair cycle arrest, also known as alopecia X. The dogs were randomly assigned to receive either two intramuscular injections of 10 mg/kg fulvestrant (6 dogs) or a saline placebo (5 dogs), with injections given one month apart. The dogs' health was monitored through blood count, chemistry panel, and urinalysis, and their hair growth was evaluated monthly. The study found that none of the dogs treated with 10 mg/kg fulvestrant showed any evidence of hair regrowth. However, one control dog that later received a higher dose of 20 mg/kg fulvestrant did experience substantial hair regrowth. No adverse effects were reported from the treatment. The study concluded that fulvestrant at a dose of 10 mg/kg is not an effective treatment for alopecia X in dogs, and while a higher dose may be more effective, it could also be cost-prohibitive.