Langerhans cell histiocytosis (LCH) is a rare proliferative disorder of histiocytes characterised by a proliferation of abnormal and clonal Langerhans cells. LCH most commonly occurs as a localised solitary bone lesion and appears predominantly in paediatric patients. This case resport presents clinicopathological features of this disorder in a 2-year-old boy. The presenting features of the patient included fever, bleeding gums and seborrheic dermatitis-like rash. Intraoral examination and radiographs revealed deep pockets and severe bone loss around all primary molars. Due to severe periodontal destruction, a gingival biopsy was taken. The biopsy specimen revealed heavy infiltration of Langerhans histiocytes. Chemotherapy was administered. Although no clear cause of LCH has been identified, the disease can be triggered by environmental agents and viruses, in particular Epstein-Barr virus. Oral manifestations may be the first or only signs of LCH. Keywords: Langerhans cell histiocytosis, periodontal disease