Immunopathogenesis of pregnancy induced lymphomatoid papulosis

A 35-year-old Caucasian female G4P4 at week one post partum with no significant past medical history was referred to our clinic for evaluation and treatment of right thigh dermatitis. Reported history suggested a recurrent dermatitis in the same location of which she believed the papules had been larger during the previous flare. Physical exam confirmed the lesions were localized to the distal right thigh with a grouping of four 2-3 mm erythematous macules, the larger papule with scales (Figure 1). Initial presentation and history placed prurigo nodularis as a top differential. A biopsy was agreed upon and later demonstrated the presence of CD4 cells, greater than 50% CD30 positive (Figure 2). A diagnosis of Lymphomatoid Papulosis (LyP) was suggested from the pathology, which correlated to her clinical picture. For further confirmation, gene rearrangement studies were requested from the biopsy.