LABD Flashcards
What is the most common type of LABD in adults?
The drug-induced type
What is the most common drug a/w drug-induced LABD?
Vancomycin
What is the prognosis for LABD in kids?
Usually spontaneous resolution within a few years
What is the definition of LABD?
Linear deposition of IgA along the cutaenous BMZ in adults or children. The disease is subepidermal and has a vesiculobullous eruption
Pathogenesis of LABD?
Depends on the etiology:
- Classically IgA antibodies directed against two related antigens derived from BPAG2 -LAD-1 (120kD cleaved protion of BP180 or BPAG2)
- LABD-97 (97kD cleaved portion of LAD-1)
- Drug-induced LABD: antibodies to Collagen VII
What diseases are a/w LABD?
Autoimmune diseases, ulcerative colitis, Crohn’s disease, gastric hypochlorhydria, infection
Clinical presentation of LABD?
Variable and patient can present with herpetiform lesions similar to DH as well as subepidermal tense bullae that are indistinguishable from BP. The vesiculobullous lesions often appear in an annular polycyclic, herpetiform arrangement (“crown of jewels” on erythematous often urticarial and or normal-appearing skin.)
Most common sites of LABD?
Flexures of lower trunk/thigh/groin/buttocks, and face (face in kids).
What is a helpful clinical clue of LABD?
Vesicopustules on the peripheral/expanding edge of plaques
Can you have mucosal involvement in LABD?
Yes, can be similar to MMP
What different morphology can drug-induced LABD take on?
TEN-like or morbilliform appearence.
What percentage of patients with LABD will have mucous membrane involvement? (adults)
50% These lesions can be scarring
What are the most common drug causes of LABD?
Vancomycin (mc) >PCN/CSN, Captopril (>other ACEI’s), NSAIDs> phenytoin, sulfonamides > lots of others
What are the clinical differences observed in drug-induced blistering disorders compared to other types?
- Self-limited
- Less mucosal involvement
- Usually does not have circulating autoantibodies
- May be more associated with antibodies to collagen VII
What is the average age of onset for childhood LABD?
4 years old, onset usually be 2-3 (think preschool age)
Disease course of childhood LABD?
Spontaneous resolution within a few years, remits by age 13
Clinical presentation of childhood LABD?
Bullae develop on erythematous or normal appearing skin (bullae arranged in a rosette or annular array “string of pearls/crown of jewels”
Most common sites of childhood LABD?
Flexural areas, particularly the lower trunk, thigh, and groin
Perioral and scalp lesions are also common, oral lesions not uncommon
What is the histology of LABD?
Cant reliable differentiate between LABD and DH on H&E, need DIF. You do see neuts diffusely along the BMZ and at the bases of the papillae as opposed to DH where it is in the papillae more.
Less tendency for papillary microabscess formation and a greater tendency for uniform neutrophil infiltration along the entire dermal-epidermal junction and rete in inflamed skin
What is seen on the DIF of LABD?
Homogeneous linear (tubular or “toothpaste”) deposition of IgA is present at the BMZ
IIF is + in 65 (circulating IgA against the BMZ)
Salt-split skin
Usually stains epidermal/roof
Deposition of IgA may be on the roof, base, or a combination of both
Treatment of LABD?
1st line: oral dapsone. average dose is 100mg/day for adults but may require more. Doses over 200mg/day require closer monitoring
Refractory cases = oral corticosteroids and immunosuppressants (may be necessary to add oral pred in doses up to 40mg daily to achieve complete control
What is the natural progression of LABD?
LABD often persists for years, with remission rates ranging from 10-60%, depending on age and disease severity.
Taper off oral medications repeatedly to see if remission has occurred
