LABD

Question 1

What is the most common type of LABD in adults?

Answer 1

The drug-induced type

Question 2

What is the most common drug a/w drug-induced LABD?

Answer 2

Vancomycin

Question 3

What is the prognosis for LABD in kids?

Answer 3

Usually spontaneous resolution within a few years

Question 4

What is the definition of LABD?

Answer 4

Linear deposition of IgA along the cutaenous BMZ in adults or children. The disease is subepidermal and has a vesiculobullous eruption

Question 5

Pathogenesis of LABD?

Answer 5

Depends on the etiology:

1. 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)

2. Drug-induced LABD: antibodies to Collagen VII

Question 6

What diseases are a/w LABD?

Answer 6

Autoimmune diseases, ulcerative colitis, Crohn’s disease, gastric hypochlorhydria, infection

Question 7

Clinical presentation of LABD?

Answer 7

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.)

Question 8

Most common sites of LABD?

Answer 8

Flexures of lower trunk/thigh/groin/buttocks, and face (face in kids).

Question 9

What is a helpful clinical clue of LABD?

Answer 9

Vesicopustules on the peripheral/expanding edge of plaques

Question 10

Can you have mucosal involvement in LABD?

Answer 10

Yes, can be similar to MMP

Question 11

What different morphology can drug-induced LABD take on?

Answer 11

TEN-like or morbilliform appearence.

Question 12

What percentage of patients with LABD will have mucous membrane involvement? (adults)

Answer 12

50% These lesions can be scarring

Question 13

What are the most common drug causes of LABD?

Answer 13

Vancomycin (mc) >PCN/CSN, Captopril (>other ACEI’s), NSAIDs> phenytoin, sulfonamides > lots of others

Question 14

Clinical differences in the drug-induced type?

Answer 14

Self-limited, less mucosal involvmenet, usually does not have circulating autoantibodies, may be more a/w antibodies to collagen VII

Question 15

What is the average age of onset for childhood LABD?

Answer 15

4 years old, onset usually be 2-3 (think preschool age)

Question 16

Disease course of childhood LABD?

Answer 16

Spontaneous resolution within a few years, remits by age 13

Question 17

Clinical presentation of childhood LABD?

Answer 17

Bullae develop on erythematous or normal appearing skin (bullae arranged in a rosette or annular array “string of pearls/crown of jewels”

Question 18

Most common sites of childhood LABD?

Answer 18

Flexural areas, particularly the lower trunk, thigh, and groin

Perioral and scalp lesions are also common, oral lesions not uncommon

Question 19

What is the histology of LABD?

Answer 19

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

Question 20

What is seen on the DIF of LABD?

Answer 20

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

Question 21

Treatment of LABD?

Answer 21

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

Question 22

What is the natural progression of LABD?

Answer 22

Persistence for several years w/ eventual spontaneous remission in many patients.

Remission rates 30-60%

Taper off oral medications repeatedly to see if remission has occurred