Hypotrichosis associated with capillary malformation-arteriovenous malformation syndrome

Background Capillary malformation-arteriovenous malformation (CM-AVM) syndrome is associated with multifocal small CMs and a high risk for high-flow lesions. It is an autosomal dominant disorder, caused by RASA1 gene mutations. Recently, two novel clinical features have been identified: numerous small pale halos with central punctate red spots, and naevus anemicus. Objectives To identify the prevalence of the new clinical manifestations in our patients with CM-AVM. The secondary objective was to investigate the presence of other skin lesions. Methods We retrospectively searched the picture database of our department for cases with a clinical diagnosis of CM-AVM, based on the identification of multiple cutaneous CMs and a negative history of epistaxis. We prospectively conducted a clinical and dermoscopic skin examination in all of these patients. Results Seven patients with multiple CMs were found, and only in one case was a cutaneous AVM present. Five patients had red punctate spots surrounded by pale halos on the upper limbs. Two adult patients also showed multiple telangiectasias on the neck and upper trunk. Naevus anemicus was not detected in any patient. A partial or total absence of vellous hair on the surface of CMs was observed in all patients. Conclusions Red punctate spots with pale halos or small telangiectasias are frequent findings in CM-AVM syndrome. Hypotrichosis on the CMs suggests that RASA1 gene mutations could be involved in the hair follicle proliferation and cell cycle.