Successful treatment of generalized inflammatory linear verrucous epidermal naevus with a somatic mutation in KRT10 with crisaborole 2% ointment.

Inflammatory linear verrucous epidermal naevus (ILVEN) is a rare skin disorder characterized by pruritic, erythematous, hyperkeratotic papules and plaques following the lines of Blaschko. The pathogenesis of ILVEN is unclear and treatment remains challenging. We analysed the molecular basis of generalized ILVEN in a 4-year-old Chinese girl and evaluated the therapeutic effect of topical crisaborole 2% ointment. The patient was found to carry a somatic heterozygous c.467G>A(p.Arg156His) mutation in KRT10. Expression of interferon-γ, interleukin (IL)-12, IL-23 and IL-17A at the mRNA level was elevated in her lesions. An excellent response was achieved after the application of crisaborole 2% ointment. Our data reveal the crucial role of activation of the immune response in the development of ILVEN with somatic KRT10 mutations. We suggest that crisaborole 2% ointment should be considered for the treatment of ILVEN.