ATOPIC DERMATITIS IN 86-YEAR-OLD MAN? BETTER THINK TWICE…

Abstract

<h3>Introduction</h3> Erythematous, pruritic rashes are commonly encountered by the Allergist. Clinicians should have awareness of the presentation and diagnostic challenge of cutaneous T-cell lymphomas to diagnose this disease instead of one of its more benign impersonators. <h3>Case Description</h3> An 86 yo man presented with six months of a pruritic rash involving his arms, back, abdomen, thighs, and buttocks. The rash was composed of dry and erythematous patches with excoriations. Serum IgE had increased from 267 IU/mL to 18,800 IU/mL during this period. Four skin biopsies demonstrated lichenoid and perivascular lymphocytic infiltrate with eosinophils, concerning for drug eruption, however, no culprit medication could be identified. Due to the clinical presentation, there was suspicion for cutaneous T-cell lymphoma, specifically early mycosis fungoides (MF). Although perivascular lymphocytic infiltrate can be found in early MF, it is non-specific, and did not confirm a diagnosis based on the criteria set forth by the ISCL. Ultimately, Clonal TRG V1-8,9 + J1/2 rearrangement was detected in peripheral blood, and the patient started oral bexarotene, a retinoic acid derivative, as treatment for MF. He underwent PET-CT and bone marrow biopsy, which were negative for peripheral T-cell lymphoma. At his most recent follow-up with Allergy, the patient had only intermittent pruritus, with no rash noted on examination. <h3>Discussion</h3> The diagnosis of early MF is challenging as the clinical and histopathological findings in the initial stages mimic a variety of inflammatory skin conditions. In this case, when biopsy results were non-specific, gene rearrangement studies were critical in leading to the correct diagnosis and treatment.