Abstract: To report the first case of Olmsted syndrome successfully treated with erlotinib in China. A 53-year-old woman presented with painful palmoplantar keratoderma on the left foot for 40 years, which had aggravated for 4 years. A plantar skin biopsy revealed a spectrum of features, including hyperkeratosis with incomplete keratosis, intracorneal edema, diminished granular layer, partial degeneration of epidermal keratinocytes, hyperplasia, and dilation of small blood vessels within the dermal papillae, concomitant with a sparse peritubular inflammatory infiltrate. Genetic detection results show heterozygous variants in the TRPV3 gene. Olmsted syndrome was made according the symptom, histopathologic findings and genetic detection. After diagnosis, oral erlotinib was administered 50 mg daily and then tapered till withdrawl. Both plantar lesions almost completely disappeared and the pain was significantly relieved after 4 months of treatment. There was no serious adverse reaction during treatment and no recurrence of rash after 2 months follow-up.

Key words: genetic diseases, Olmsted syndrome, erlotinib, TRPV3 gene