Idiopathic linear IgA bullous dermatosis: prognostic factors based on a case series of 72 adults.

BACKGROUND: Linear IgA bullous dermatosis (LABD) is a clinically and immunologically heterogeneous, subepidermal, autoimmune bullous disease (AIBD), for which the long-term evolution is poorly described. OBJECTIVES: To investigate the clinical and immunological characteristics, follow-up and prognostic factors of adult idiopathic LABD. METHODS: This retrospective study, conducted in our AIBD referral centre, included adults, diagnosed between 1995 and 2012, with idiopathic LABD, defined as pure or predominant IgA deposits by direct immunofluorescence. Clinical, histological and immunological findings were collected from charts. Standard histology was systematically reviewed, and indirect immunofluorescence (IIF) on salt-split skin (SSS) and immunoblots (IBs) on amniotic membrane extracts using anti-IgA secondary antibodies were performed, when biopsies and sera obtained at diagnosis were available. Prognostic factors for complete remission (CR) were identified using univariate and multivariate analyses. RESULTS: Of the 72 patients included (median age 54 years), 60% had mucous membrane (MM) involvement. IgA IIF on SSS was positive for 21 of 35 patients tested; 15 had epidermal and dermal labellings. Immunoelectron microscopy performed on the biopsies of 31 patients labelled lamina lucida (LL) (26%), lamina densa (23%), anchoring-fibril zone (AFz) (19%) and LL+AFz (23%). Of the 34 IgA IBs, 22 were positive, mostly for LAD-1/LABD97 (44%) and full-length BP180 (33%). The median follow-up was 39 months. Overall, 24 patients (36%) achieved sustained CR, 19 (29%) relapsed and 35% had chronic disease. CR was significantly associated with age > 70 years or no MM involvement. No prognostic immunological factor was identified. CONCLUSIONS: Patients with LABD who are < 70 years old and have MM involvement are at risk for chronic evolution.

[Bullous rash around a peritoneal dialysis catheter exit site]. / Éruption bulleuse péri-ombilicale autour d'un cathéter de dialyse péritonéale.

BACKGROUND: Cutaneous eruption around a peritoneal dialysis (PD) catheter exit site is a rare complication. Herein we report a case of bullous eruption; we discuss the diagnostic approach and the related therapeutic implications. PATIENTS AND METHODS: A 63-year-old man presented a bullous periumbilical eruption two months after initiation of PD. Cultures of laboratory samples ruled out an infectious origin and systemic corticosteroids initiated at 0.5mg/kg for suspected eosinophilic peritonitis produced significant improvement of the cutaneous eruption. Recurrence of the bullous eruption was observed upon dose-reduction of the corticosteroid. Skin histology showed a clinical picture of eczema and direct immunofluorescence was negative. Patch testing was carried out using the European Standard Battery comprising antiseptic, cosmetic and plastic series; a semi-open test was performed with the dressing used for PD, and ROAT was carried out on the povidone iodine (Betadine™) 10% used for topical care during PD. The patch testing and ROAT were positive (++), confirming contact dermatitis due to Betadine™. The eruption totally disappeared on substitution of Betadine™ by chlorhexidine for topical antisepsis of the PD catheter, thus enabling PD to be continued rather than instituting hemodialysis. DISCUSSION: Allergic contact dermatitis around a PD catheter is a rare and little-known complication. In the present case, ROAT testing showed sensitization to Betadine™ and enabled an alternative antisepsis solution to be found, allowing PD to be continued.