Trichoscopic Findings of Erosive Pustular Dermatosis of the Scalp Associated with Gefitinib.

Alopecia associated with epidermal growth factor receptor (EGFR) inhibitor therapy is a rare cutaneous side effect with the potential to progress to scarring alopecia. Thus, dermatologists should make an early diagnosis. We present the case of a 57-year-old Japanese female with scarring alopecia associated with gefitinib, which is an EGFR inhibitor, including trichoscopic findings. The patient treated with gefitinib for non-small cell lung cancer experienced skin rash and hair loss of the scalp. The scalp lesions appeared similar to erosive pustular dermatosis of the scalp. Trichoscopic examination showed follicular keratotic plugging, milky red areas, white patches, hair shaft disorder, tapering hair, and absence of follicular opening. Histological examination showed ruptured hair follicles with a perifollicular infiltration of plasma cells, lymphocytes, and histiocytes. Oral minocycline and topical steroid treatment produced no improvement. With a reduction in the gefitinib dosage, alopecia gradually improved, although scarring remained. We consider these trichoscopic findings and suspect that follicular keratotic plugging might be a finding associated with scarring alopecia due to EGFR inhibitor therapy.