[A stereotypical clinical presentation of childhood linear purpura of the arms: Analysis of six cases]. / À propos de 6 cas de purpura linéaire des bras de l'enfant : une présentation clinique stéréotypée.

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.

[IgE mediated anaphylaxis in a patient with systemic mastocytosis]. / Anaphylaxie médiée par les IgE chez un patient atteint de mastocytose systémique.

BACKGROUND: Anaphylaxis is a severe, generalized, life-threatening reaction of rapid onset. We report the case of a patient presenting several systemic anaphylactic reactions over many years, initially ascribed to a cereals allergy but which finally proved to be due to systemic mastocytosis hidden for a long time. PATIENTS AND METHODS: A 53-year-old man consulted for an eruption consisting of monomorphic pigmented maculopapular lesions on the trunk associated with itching and urticaria. He was a farmer and presented severe sensitivity to cereals, with anaphylaxis, which continued despite withdrawal of these allergens. Skin and bone marrow infiltration, abnormal mast cells, positivity for c-kit 816 mutation and the persistent elevation of serum tryptase enabled a diagnosis of indolent systemic mastocytosis to be made. DISCUSSION: In systemic mastocytosis anaphylaxis is an expected complication relating to the proliferation of mast cells and a massive increase in mediator release (non-immunological mechanism). All patients with severe and recurrent anaphylaxis should be analyzed for underlying mastocytosis by careful physical examination and assay of baseline tryptase.

[Antidesmoglein antibodies in a patient with Hailey-Hailey disease]. / Détection d'anticorps antidesmogléines circulants chez un patient atteint de maladie de Hailey-Hailey.

BACKGROUND: Hailey-Hailey disease (HHD) is a rare hereditary disease in which the genetic defect is characterized by mutation in the ATP2C1 gene coding for a transmembrane calcium pump. It is generally considered a non-immunologic acantholytic dermatosis in which direct and indirect immunofluorescence studies are negative, unlike in autoimmune pemphigus. PATIENTS AND METHODS: We describe a case of HHD associated with antidesmoglein antibodies in a 53-year-old woman. The clinical symptoms and histology were typical of HHD. Antidesmoglein antibody tests were positive on several occasions and a difference was found between the two types of Elisa test performed (positive with the MBL kit, negative with the Euroimmun kit). DISCUSSION: The positive result for desmoglein antibodies could be due to unmasking of antigens by the mechanism of acantholysis. The specificity of the main desmoglein Elisa tests also requires discussion.