At the Root: Cutaneous Langerhans Cell Histiocytosis

The document reports on a 33-year-old woman who suffered from scalp eruptions, intense itching, and hair loss for 15 years, initially misdiagnosed as seborrheic dermatitis and female androgenic alopecia. Despite treatment with topical steroids, her symptoms persisted. A physical exam showed hair thinning and erythematous, scaling papules without scarring alopecia, and laboratory tests were normal. A biopsy revealed a dermal infiltrate of Langerhans cells, which was confirmed by immunohistochemical analysis, although she did not have the BRAF V600E mutation commonly associated with Langerhans cell histiocytosis (LCH). She was diagnosed with cutaneous LCH, a rare malignant disorder, and had no internal organ involvement. She began treatment with oral methotrexate, which led to moderate improvement. This case emphasizes the need to consider LCH in persistent skin conditions unresponsive to standard treatments.