An Infant with Petechial Rash in Seborrheic Dermatitis Pattern: A Rare Case of Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disorder of immature dendritic cells. The clinical features mimic various disorders, posing a clinical challenge for the treating physicians. A 10-month-old-boy presented with repeated episodes of seborrheic dermatitis since an early age of life. He had a peculiar petechial component in seborrheic rash affecting the scalp, face, and groin. He had significant hepatosplenomegaly and ear discharge. Histopathological examination revealed histiocytic infiltration of the dermis. Immunohistochemistry showed positive staining for CD1a and S100. On this basis, a diagnosis of LCH was made. A high index of suspicion by the clinician is necessary as the disease is rare and mimics various cutaneous disorders. In unresponsive, repeated episodes of seborrheic dermatitis presenting with petechial rash in infants, one must rule out the LCH. Aggressive treatment is needed in multisystem disease; so early diagnosis and initiation of treatment are essential.