Langerhans cell histiocytosis (LCH) limited to the skin is rare in adult patients. Given the challenges of prospective clinical trials for this rare disease, there is paucity in data to guide the management of cutaneous LCH. Topical nitrogen mustard is a possible treatment for cutaneous LCH with positive responses in five known adult cases in the literature. In this report, we present two adult patients with recalcitrant cutaneous LCH and no evidence of systemic involvement who had rapid and complete response on topical nitrogen mustard therapy. We provide support for topical nitrogen mustard as a treatment option for primary cutaneous LCH which may spare patients from requiring systemic immunosuppressive treatments. J Drugs Dermatol. 2020;19(8):803-805. doi:10.36849/JDD.2020.4943.