Two Cases of Paradoxical Nonscarring Alopecia after Mesotherapy with Dutasteride.

Alopecia after mesotherapy with dutasteride is an extremely rare complication. Dutasteride is a second-generation 5a-reductase enzyme inhibitor that decreases serum dihydrotestosterone levels by 90%. It inhibits both type 1 and 2 enzymes, whereas finasteride inhibits only type 2. Mesotherapy with dutasteride is a novel treatment for hair fall which involves microinjection of the drug into the dermis with negligible systemic absorption. Frequent mild transitory side effects in the site of injection are described in medical literature, but few cases of secondary alopecia have been reported. This stands out given that mesotherapy is becoming such an increasingly common procedure with a great number of patients treated with this technique. We present 2 cases of patchy alopecia after mesotherapy with dutasteride in a male and a female with androgenetic alopecia. One of them developed skin atrophy on the affected areas without improvement at short term follow-up. These cases highlight the possible paradoxical side effects of mesotherapy as a therapeutic technique for hair loss.