Diverse Cutaneous Presentations of Langerhans Cell Histiocytosis in Children: A Retrospective Cohort Study

Background Langerhans cell histiocytosis (LCH) is a rare disease, frequently affecting young children. Procedure We performed a retrospective study in patients younger than 16 years old manifesting with skin symptoms, and documented their different cutaneous lesions and systemic symptoms. We compared subgroups of children with single‐system, skin‐only, and multisystem disease and sought signs predictive for multisystem disease. In a small sample of patients, BRAF mutations were analyzed in archived biopsies. Results A wide spectrum of cutaneous presentations varying from crusted nodules and papules, blisters, vascular tumor‐like lesions, scaling orange to red macules (frequently in seborrheic regions) to purpuric macules, and papules was documented in our cohort of 32 children. Otitis externa was a common manifestation and mucosal lesions were seen in three patients. A novel manifestation was a red‐blue nodule that appeared in a patient after a vaccination. None of the cutaneous lesions was predictive for the classification or final outcome as a single‐system or multisystem disease. However, later onset and a more protracted course of skin lesions were more frequent findings in multisystem LCH. Mucosal lesions and otitis externa were almost exclusively seen in patients with multisystem disease, a finding that warrants further investigation. Both wild‐type (WT) and mutated BRAF were found not only in multisystem LCH, but also in skin‐only LCH. Two cases with rapidly resolving congenital lesions had WT BRAF. Conclusions Late onset and a protracted course of skin lesions are associated with MS‐LCH, whereas WT BRAF is found in rapidly resolving skin lesions.