Variable response to low-dose naltrexone in patients with Darier disease: a case series.

BACKGROUND: Darier disease is a rare autosomal-dominant genodermatosis with a loss of function of a Ca2+ -ATPase pump (SERCA2-pump). Clinically, the disease is characterized by red-brown keratotic papules mainly in seborrhoeic areas and has only limited and unsatisfactory treatment options. Previously, low-dose naltrexone was described as a successful treatment option in Hailey-Hailey disease, a genodermatosis with a genetic mutation coding for a similar loss of function of a Ca2+ -ATPase pump (hSPCA1-pump). OBJECTIVE: To assess the efficacy of low-dose naltrexone as a treatment option in Darier disease. METHODS: Six patients with biopsy-proven Darier disease (four had severe, one had moderate and one mild clinical manifestations). The patients received off-label therapy with naltrexone [5 mg per os (p.o.)] and magnesium [200 mg p.o.]. Patients were followed up every 4 weeks for minimally 12 weeks. Upon clinical presentation, the disease severity and subjective pain and itch scores were assessed, and standardized photographs were obtained. RESULTS: The clinical response to naltrexone varied after 12 weeks. The four patients with severe Darier disease showed worsening after initial improvement during the first 4 weeks, whereas the two patients with a mild to moderate clinical manifestation clearly improved, showing almost full remission after 12 weeks with complete flattening of the keratotic papules. CONCLUSION: Low-dose naltrexone did not have an effect on severe Darier disease compared to Hailey-Hailey disease, but it was beneficial in mild to moderate forms of the disease. Further studies are needed to confirm these observations of variable responses.