Dermatologic Features of Smith-Magenis Syndrome

Smith–Magenis syndrome (SMS) is characterized by distinctive facial and skeletal features, developmental delay, cognitive impairment, and behavioral abnormalities, including self‐injurious behaviors. We aimed to investigate whether cutaneous features are common in SMS. We performed a complete skin examination in 20 young SMS patients. Skin features secondary to self‐injurious behavior, such as bites, abrasions, dystrophic scars, limited spots of hyperkeratosis, anomalies of the nails, and whitlows, were found in the majority of patients. Acral pachydermia and fissured plantar keratoderma were common. Xerosis was constant and associated with extensive keratosis pilaris in the majority of patients. Dermatofibromas were frequent in older patients. The hair was dense and shiny, with an unusual hairline. Eyelash trichomegaly and heavy brows were common, as well as folliculitis on the back. The skin features of SMS have rarely been reported in the literature. Some of these are the consequence of neurobehavioral features, but some cutaneous features and abnormalities of appendages have not been reported in other related syndromes. Skin manifestations of SMS are varied, sometimes induced by self‐injurious behavior and sometimes more specific. It remains to be determined whether the combination of the two kinds of signs could contribute to early diagnosis of the syndrome.