EBAtype VII collagenmechanobulloussalt-split

Epidermolysis Bullosa Acquisita (EBA)

אפידרמוליזיס בולוזה נרכשת

📖 מבוא

Epidermolysis Bullosa Acquisita (EBA) — מחלה אוטואימונית נדירה עם נוגדנים נגד type VII collagen (anchoring fibrils, sublamina densa). Mechanobullous form (skin fragility, trauma sites) vs Inflammatory form (mimics BP/LABD). קשר ל-IBD. Bologna Ch 115.

📝 אנמנזה

בועות ושלפוחיות — trauma sites (ידיים, רגליים, מרפקים, ברכיים)? שבריריות עור? millia? צלקות? בועות inflammatory? תחילת המחלה — חריפה/הדרגתית? IBD (Crohn, UC)? SLE?

🔍 בדיקה

Mechanobullous (classic, 60%): שבריריות עור, blisters at trauma sites (dorsal hands, feet, elbows, knees). Tense blisters → erosions → scarring + milia (pathognomonic). Nail dystrophy/loss. Resembles hereditary DEB. Inflammatory (40%): widespread tense blisters — mimics BP or linear IgA disease. Mucosal involvement: oral, esophageal, ocular — strictures/scarring.

📋 סיכום

חשד ל-EBA. בירור אימונולוגי.

💊 המלצות

🔬 בירור

-ביופסיה: subepidermal blister with minimal inflammation (mechanobullous) or neutrophilic infiltrate (inflammatory). DIF (perilesional skin): linear IgG at BMZ — ⚠️ same pattern as BP! Salt-split skin DIF: IgG on DERMAL side (floor of blister) — KEY differentiator from BP (epidermal/roof side). IIF: anti-type VII collagen antibodies (ELISA — most specific). Electron microscopy: sub-lamina densa deposits.

-DDx: Bullous pemphigoid (IgG on EPIDERMAL side of salt-split, anti-BP180/BP230), Porphyria cutanea tarda (urine porphyrins↑, photodistribution), Hereditary DEB (childhood onset, family history, COL7A1 mutation), Linear IgA bullous dermatosis (IgA at BMZ, string-of-pearls), Bullous SLE (ANA+, anti-dsDNA+).

-הפניה: dermatology tertiary center + rheumatology. מעקב: CBC, CMP (dapsone monitoring). GI evaluation if IBD suspected.

💊 טיפול

-טיפול: ⚠️ Notoriously difficult to treat. Colchicine 0.5-1.5 מ"ג/יום — first-line for mechanobullous, mild-moderate. Dapsone 50-200 מ"ג/יום (⚠️ G6PD screen) — especially inflammatory form. Systemic steroids + steroid-sparing: Mycophenolate, Azathioprine, Cyclosporine. Rituximab — emerging as effective for refractory EBA. IVIG — adjunctive. Wound care — non-adhesive dressings, silicone. ⚠️ Avoid trauma, friction.

⚗ מרשם

-PO COLCHICINE 0.5 mg x2-3/d (first-line, mechanobullous) - 1OP

-PO DAPSONE 50-100 mg/d (inflammatory form, ⚠️ G6PD screen) - 1OP

-PO PREDNISONE 0.5-1 mg/kg/d + MYCOPHENOLATE 1g x2/d (severe) - 1OP