Abstract

Use of epidermal growth factor receptor (EGFR) inhibitors is a rare but increasingly recognized cause of alopecia, with few reports detailing the associated histopathological features. We report two cases of EGFR inhibitor-associated scarring alopecia in patients undergoing therapy for metastatic lung adenocarcinoma. Patient A, a 73-year old woman, presented three months after starting osimertinib with hair loss and a scaly erythematous dermatitis of the vertex scalp with crusting that was refractory to ciclopirox and fluocinonide solution. Patient B, a 68-year old woman, presented three months after starting erlotinib with purulent, crusted erythematous papules and nodules associated with scarring diffusely involving the scalp, eyebrows, and suprapubic area that was refractory to doxycycline, ketoconazole shampoo, and fluocinolone. Scalp biopsies from both patients showed a folliculitis decalvans-like eruption with a robust perifollicular inflammatory infiltrate composed of neutrophils, plasma cells, lymphocytes, and histiocytes centered on the infundibulum. There was polytrichia and dermal fibrosis with loss of sebaceous units. In addition, the biopsy from Patient A showed vacuolar interface reaction, scattered eosinophils, and impetiginization. Patient A improved after treatment with oral doxycycline, clobetasol, and ciclopirox solution. Patient B experienced significant improvement after transitioning from erlotinib to osimertinib. These cases highlight the need for increased awareness of EGFR-associated alopecia, particularly in light of the increasing use of these medications in oncologic patients. They also underscore the critical role of the EGFR signaling cascade in homeostasis of epidermal keratinocytes and hair follicles, as well as the need for a more in-depth understanding of this pathophysiological process to inform future therapeutic modalities.

Financial Disclosure:
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