Naltrexone in standard and reduced doses is efficacious in many inflammatory and acantholytic disorders.

We summarized the current data of naltrexone that are relevant to dermatologic practice.

An English language PubMed literature search was performed using the terms naltrexone, low-dose naltrexone, Hailey–Hailey, psoriasis, lichen planopilaris, alopecia, opioid, opioid receptor, treatment, dermatology, monitoring, side effect, skin, pruritus, cutaneous, acantholytic, and Darier.

Opioid receptors are found throughout the skin and affect cell proliferation, migration, and adhesion. μ Opioid receptors have been found in all layers of the epidermis, while δ receptors are concentrated at cell junctions and can reduce desmoglein expression. Typical doses of naltrexone result in continuous binding to receptors. Low doses result in intermittent blockade with increased ligand and receptor expression, potentiating their effect.

Our review was restricted to the English language literature.

Naltrexone affects inflammation, cell adhesion, and keratinocyte proliferation and migration. While low-dose naltrexone has demonstrated efficacy in treating patients with Hailey–Hailey disease, further dose-ranging studies are needed. Data suggest that naltrexone could be helpful in the treatment of pruritus and a variety of inflammatory and acantholytic skin diseases that are refractory to other treatments. At higher doses, liver function tests should be monitored on a periodic basis.