[A stereotypical clinical presentation of childhood linear purpura of the arms: Analysis of six cases].

Among causes of childhood purpura, other- or self-induced mechanical purpura, such as factitious purpura, needs to be considered. This cause is unfamiliar to pediatricians, usually compromising early diagnosis. We report on the cases of six children, seen between 1998 and 2014 at the Toulouse and Bordeaux Departments of Dermatology, presenting with a stereotypical linear purpura on the arms. All were females, aged 6-14 years. One patient had a psychiatric history, whereas the others were undergoing a stressful time period. All had several relapses and diagnosis was delayed in all. The patients presented with multiple oval or square purpuric macules, forming a discontinuous linear band. Some patients reported functional discomfort such as pain or pruritus. Lesions were always located on the arms and sometimes on other areas of the body. Biological assessments were normal and there was no vasculitis at skin histology. We retained the diagnosis of induced mechanical purpura. Psychological support was offered to four patients. One of them declared that the lesions were induced by classmates using suction. Another child declared that she caused the lesions herself, without explaining the mechanism. Outcome was favorable in five children (one was lost to follow-up), 1-4 years after diagnosis. In conclusion, induced mechanical purpura in children, although rarely described in the medical literature, must be kept in mind. Investigations should be carried out in cases with uncertain diagnosis. Underlying psychological distress should be sought.