Dermatitis herpetiformis/ LABD chapter Flashcards

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1
Q

Describe the classic lesions of what is seen here

A

Most commonly we see urticarial plaques, papules and vesicles that can be grouped/ herpetiform on an erythematous base, symmetric dist. favoring the elbows, knees, extensor forearms, back and buttocks’

pruritic papulovesicles or excoriated papules on extensor surfaces

neutrophilic infiltration of the dermal papillae with vesicle formation at DEJ

granular IgA deposition within dermal papillae in clinically normal skin adjacent to lesion

a response to dapsone therapy (but not the intestinal disease)

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2
Q

What is the strong genetic association with DH?

A

HLA DQ2

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3
Q

topical iodide on normal skin of patients with a history of DH (or ingestion of iodide) can cause what?

DH is associated with which two other autoimmune conditions commonly?

A

new lesions / neutrophil chemotaxis! (follicular neutrophilic pustules)

a/w insulin dependent DM and hashimoto’s thyroid dz

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4
Q

H&E, explain what you see

A

This is DH

Subepidermal clefts beneath which are collections of neutrophils within dermal papillae. Scattered eosinophils are also present.

For routine histology, it is optimal to capture a small, intact vesicle. If this is not available, an area of erythema should be biopsied. Areas of erythema will show dermal papillary edema and neutrophil infiltration associated with a superficial perivascular lymphocytic infiltrate. Dermal papillae filled with neutrophils, with relative sparing of the lowermost tips of the intervening rete ridges, is a characteristic finding. When an intact vesicle is biopsied, a subepidermal blister containing predominantly neutrophils will be seen

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5
Q

Why is it optimal to biopsy adjacent, but not inside a lesion of DH for DIF?

which autoantibodies can be found in labs?

A

A false-negative DIF can occur if lesional skin is biopsied, since the inflammatory infiltrate can destroy the IgA

IgA anti-TTG3 Anti-endomysial antibodies = specific for CD/ DH

Granular IgA is pathognomonic

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6
Q

Ddx for DH?

A

Top row= arthropod bite (hypersensitivity rxn to bug bite)

bottom row = papular urticaria

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7
Q

DH Ddx

A

top left = BP

top mid = LABD

top right = urticarial vasculitis

EM

bullous LE

Granulomatosis w/ ?

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8
Q

Front/ back - which disease?

Discuss epidemiology/ main causative agent?

A

LABD

F> M

bimodal → 4-5 yo and >60yo

MCC is Vanco

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9
Q

What is primary IgA autoantibody target?

A

BP180 / BPAG2 (specifical LAD-1/ LABD97)

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10
Q

Difference between LABD and DH on DIF?

A

Linear IgA along BMZ in LABD and granular IgA deposition in DH - both in adjacent skin

Also note: Can have mucosal involvement with LABD

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11
Q

LABD treatment

A

Dapsone, Sulfapyridine, colchicine

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12
Q

Starting from top left to top right

A
  • EBA
  • Localized EBS
  • Friction blister
  • Bullous diabetacorum
  • Coma blister (pt had some phenobarbital
  • bullous insect bites (immunosuppressed HIV/hematologic malignancy//kids)
  • bullous impetigo-edema blisters (person has anasarca)
  • localized BP
  • postburn blisters

– self induced (bullous dermatitis artefacta)

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13
Q

What do you think of here?

A
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14
Q

Which drug can cause LABD?

How about BP?

How about PV?

A

Vanco > B-Lactams

BP = Diuretics/ abx

PV = captopril/ penicillamine, b lactams

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15
Q

How do you know this is coma blister?

A

epidermal necrosis, sweat gland necrosis (characteristic), focal necrosis of epithelium of pilosebaceous follicles

no distinct cellular infiltrate

no Ig’s on DIF

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16
Q

Describe basic pathology of a friction blister?

A

intraepidermal blister resulting from necrosis of keratinocytes, usually at the level of the stratum spinosum just below stratum granulosum, the roof of blister forms in stratum corneum

sparse perivascular infiltrate

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17
Q

Back of teh hands blisters makes you think of?

What variation is seen here?

A

porphyria

drug induced here → NSAIDS, thiazides, furosemide, tetracyclines

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18
Q

What do you see here? What else on ddx?

What medication likely caused this?

A

This is AGEP

Pustular psoriasis on ddx

Caused by -Beta lactams, macrolides, pristinamycin, CCB, plaquenil, etc. etc.

Acute onset, usually occurring within 2 days of drug exposure

Areas of erythema studded with pustules; occasionally vesicles

Fever, malaise, leukocytosis

19
Q

What is seen here

A

Photo distributed rash

Resembles exaggerated sunburn

Phototoxic drug eruption

think doxycycline (tetracyclines), quinolones, psoralens, nsaids, diuretics

20
Q

What the heck is going on here

A

Bromoderma/ iododerma

Acneiform lesions, papulopustules, nodules, or even vegetating lesions simulating pemphigus vegetans

Clear or hemorrhagic blisters can develop (more common in iododerma)

21
Q

What is seen here?

A

Palmoplantar erythrodysesthesia

  • Acral variant of toxic erythema of chemotherapy
  • Cytarabine, doxorubicin, capecitabine, 5-fluorouracil (especially prolonged infusions), multikinase inhibitors (e.g. sorafenib, sunitinib), busulfan, taxanes, clofarabine, pralatrexate
22
Q

Bullous insect bite rxns

epidemiology

Hematologic malignancy associations?

Pathogenesis

What do you seen on H&E

A

•Epidemiology–Children–

Hematologic malignancy = CLL > mantle cell lymphoma, NK/T-cell lymphoma

Path = immune response t oinsect Ag (IgE mediated and delayed/ cell mediated)

Path → eosinophilic spongiosis, Intraepidermal > subepidermal blister (may occur if dermal edema severe), –Superficial and deep perivasc/periadnexal lympho-eosinophilic inflammation (+/- flame figures), Superficial dermal edema

23
Q

What type of bulla?

A

Delayed posburn/ post graft blisters

  • happen at site of prev. trauma/ >30% involvement increases reoccurence rate
  • tense vesicles/ bulla appearing wks/months after original wound has healed, d/t fragility of new DEJ
    • path shows cell-poor subepidermal blister, NO DIF findings
24
Q

What do you see here?

A

bullous dermatitis artefacta

25
Q

LABD → IgA autoantibodies directed at _____, which is broken into two antigens: 1) ____ and 2) ____

A

BPAG2

Broken into LAD-1 and LABD97

26
Q

can linear IgA have mucosal involvement?

A

Yes, similar to MMP

27
Q

Histopath of LABD

Early versus late?

A

Fully developed lesions show subepidermal blisters with infiltrates of lymphocytes, eos and neuts

Expect more Neuts than others

vacuolar degeneration at the BM zone

Neutrophilic dermal papilla accumulation, similar to DH

DIF shows linear IgA deposits along BMZ

Salt split shows binding to epidermal side of the split

28
Q

EBA is acquired or genetic?

Adults or kids?

Associated conditions?

A

Acquired

Adults

Crohns/ IBD > Myeloma, SLE, RA,

29
Q

Which autoantibody for EbA

Which MHC association?

A

IgG against Collagen 7 NC1 domain

Class 2 HLA-DR2

30
Q

Where does mechanobullous EBA affect?

Inflammatory EbA

A

Acral/ trauma prone sites ( may result in mitten deformities) → syndactyly, nail dystrophy/ loss, bullous lesions heal w/ atrophic scars, milia, dyspigmentation

Inflammatory → widespread (BP LIKE), indistinguishable from BP, widespread vesicles/ bulla with NO scarring/ millia after healing (mechanical EBA heals with scarring)

Inflammatory also has eye/ mouth involvement, also esophageal

31
Q

DIF for EBA shows →

A

Borad linear band of IgG with a U serrated pattern along BMZ

Opposite of BP (Linear C3 with an N-Serrated pattern)

Salt split skin shows DERMAL side staining

32
Q

Mechanical EBA vs. Inflammatory EBA on Histology>?

Which substrate for EBA?

A

Mech → cell poor sub epidermal blister (occasional EOs)

Inflammatory → moderately dense lymphocytic infiltrates with eos’/ neuts

Early urticarial lesions are not distinguishable from early lesions from other disease (BP?), vacuolar degeneration of BMZ, eosinophilic spongiosis common

Blisters localize to sublamina densa region

Monkey Esophagus

33
Q

In contrast to DH, bullous Lupus lymphocytic inflitrate is more concentrated around the ____

Bullous Lupus DIF shows

A

Hair Follicles versus dermal papilla (DH)

Linear AND or granular IgG, IgA, IgM and C3 (full house)

34
Q

HistoPathology of friction blisters

A

intraepidermal split, necrosis of keratinocytes

Split usually mid spinosum

pale and degenerated keratinocytes

Think of localized EB → weber cockayne

35
Q

Which autoantibody for GUT involvement of DH?

How about skin involvement?

A

GUT → Anti TTG2 IgA ab

Skin → Anti TTG3 IgA ab

36
Q

DH a/w which other autoimmune diseases?

A

–Hashimoto’s thyroiditis (>50%) > IDDM > pernicious anemia >> Addison’s, AA, myasthenia gravis, vitiligo, SLE

37
Q

What DIF pattern do you expect to see in DH?

A

Granular IgA deposited within the dermal papilla

38
Q

Which HLA types for DH?

A

DQ2 >90%

DQ8 <10%

39
Q

bullous arthropod assault bugs associated? (2)

A

fleas and bed bugs

think kids and people with cancer (CLL)

40
Q

delayed postgraft burns appear when

how much TBSA is usually seen?

A

30-37 days after

TBSA >30%

41
Q

which stain for neonatal cephalic pustulosis

A

giemsa stain

42
Q

looks like neonatal cephalic pustulosis but isn’t just on the head?

A

ETOX/ ETN

43
Q

TNPM or ETN first???

A

TNPM