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Flashcards in Pemphigoid Group Deck (61)
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1
Q

What is the most common autoimmune blistering disease?

A

Bullous pemphigoid

2
Q

What is the epidemiology of bullous pemphigoid?

A

M/c in older ages >60 M>F

3
Q

What is the pathogenesis of bullous pemphigoid?

A

IgG1 and IgG4 bind to hemidesmosomal proteins (BPAG-2 is pathogenic, BPAG-1 isn’t) –> complement activation –> eos and neutrophils recruited to area –> MMP’s proteases, neutrophil elastase –>degredation of ECM proteins –> subepidermal blister

4
Q

What are the target antigens in bullous pemphigoid?

A

BP180 (BPAG2 or type XVII collagen): transmembrane protein; primary mediator of BP NC16A : non-collagenous extracellular domain,

Non-pathogenic target BP 230 (BPAG1): cytoplasmic protein belonging to the plakin family, antibodies arise d/t epitope spreading

5
Q

What is gestational pemphigoides

A

Closely related to BP, the transplacental transfer of autoantibodies to BP180 from the mother into the neonate can result in a transient bullous eruption

6
Q

What are the clinical features/varients of bullous pemphigoid?

A
  • Non-bullous phase: Nonspecific, mild to severe intractable pruritus +/- excoriated, eczematous, popular and/or urticarial lesions persisting for weeks to months
  • Bullous phase: Tense, fluid-filled vesicles/bullae on urticarial background; trunk, abdomen, flexural extremities +10% with oral involvement +50% with peripheral blood eosinophilia
  • Less common variants: Dyshidrosiform pemphigoid, clusters of vesicles and bullae appear on acral skin and can resemble dyshidrotic eczema or pompholyx.
  • Pemphigoid vegetans, vegetating plaques can develop in major body folds, including the inguinal crease.
  • Toxic epidermal necrolysis-like lesions with large erosions.
7
Q

Top medications for drug-induced pemphigoid?

A

Furosemide (#1), Ace inhibitors, cephalosporins, beta-lactams, D-penicillamine, sulfasalazine, NSAIDS, neuroleptics, gold, SSKI, bumetanide, phototherapy, DPP-4 inhibitors (gliptins), and checkpoint inhibitors like pembrolizumab

8
Q

Clinical presentation of infantile/childhood BP?

A

P/w acral blisters first often and then generalizes. There is more facial and genital involvement. Looks just like childhood LABD/CBDC –> need DIF to tell the difference.

9
Q

What is lichen planus pemphigoides?

A

So this is an LP/BP overlap, so you get circulating antibodies against BP 180 and then you get the blisters on skin unaffected by the LP lesions. This is different from bullous LP which is blisters on existing LP lesions.

10
Q

What is pemphigoid nodularis?

A

Looks like prurigo nodularis but lacks bullae

11
Q

Common sites for localized BP?

A

Pretibial, peristomal, vulval, umbilical, distal portion of amputated limb, radiotherapy sites and paralyzed limbs

12
Q

What is the anti-p200 pemphigoid?

A

Most often presents with classic BP lesions, head and mucous membranes are more often affected. Often a/w psoriasis, the target antigen is laminin gamma1

Salt split skin = dermal side

13
Q

What side of salt split skin do the antibodies in anti-p200 pemphigoid antibodies stick?

A

Dermal side

14
Q

What is anti-p150 pemphigoid

A

Extensive blistering seen on skin and mucous membranes, can resemble SJS/TEN. Target antigen is the 105kDa protein

15
Q

What side of salt split skin do the antibodies in anti-p150 pemphigoid antibodies stick?

A

Dermal side

16
Q

What is gestational pemphigoid?

A

Abrupt onset, any trimester (2nd and third most common). Immediately postpartum or a/w trophoblastic tumors (choriocarcinoma, hydatiform mole); starts as urticarial/vesicular plaques on trunk abdomen, umbilicus then rapidly generalizes. 75% flair at the time of delivery.

17
Q

What HLA type is a/w pemphigoid gestationis?

A

HLA-DR3 (70%), DR4 (50%), or both (45%).

18
Q

What does the DIF show in pemphigoid gestationis?

A

Linear C3 in 100% and linear IgG in 30%. IIF is only + in 30% of cases

19
Q

What is the best serum test for pemphigoid gestationis?

A

Serum ELISA for BP180-NC16A.

20
Q

Risk to the fetus in pemphigoid gestationis?

A

Risk of premature delivery and SGA neonates. Neonates may also get transient blistering (10%).

21
Q

Does pemphigoid gestationis recur?

A

Yes, it tends to recur with each pregnancy

22
Q

What autoimmune disease is pemphigoid gestationis a/w?

A

Graves disease and anti-thyroid antibodies.

23
Q

Treatment of pemphigoid gestationis?

A

Systemic CS

24
Q

How do you diagnosis bullous pemphigoid?

A

Biopsy for H&E and for DIF (most sensitive) C3>IgG

Serum ELISA for NC16A domain of BP180 and C-terminus (+/- the N terminus of BP230) [80-90% sensitive]

IIF: Serum test for circulating anti-BMZ IgG; the substrate you use is salt split NORMAL human skin (not the patient’s skin!) [60-80% sensitive]

25
Q

Bullous pemphigoid normal human salt split skin findings?

A

Epidermal (roof) staining, note that the IIF levels do NOT correlate well with disease activity unlike IIF for PV

26
Q

What level of skin does the salt splitting technique split the skin at? and what things bind to the epidermal vs dermal side?

A

Salt splitting cleaves the skin at the lower portion of the lamina lucida.

  • Things in the epidermis: BP, pemphigoid gestationis, linear IgA bullous dermatosis, mucous membrane pemphigoid
  • Things in dermal side: anti-epiligrin mucus membrane pemphigoid (Laminin 332), epidermolysis bullosa acquista, bullous eruption of systemic lupus erythematosus
27
Q

What is the treatment of bullous pemphigoid?

A

It is recommended to treat for 6-12 months with prednisone plus 1-6 months after cessation of clinically active disease

  • Oral prednisone at dose of .5-1mg/kg/day to control dz
  • Other steroid-sparing agents (azathioprine, mycophenolate mofetil, etc)
  • For localized dz: superpotent topical CS, nicotinamide (500-2000mg/day) + tetracycline, doxycycline or minocycline
  • Treatment-resistant cases: IVIg, plasma exchange or anti-CD20 immunotherapy (rituximab) or omalizumab
28
Q

What is the prognosis of BP?

A

Chronic, 30% of pt’s have a relapse during the first year of treatment, 50% relapse within the first 3 months after stopping tx.

Does eventually remit, often after ~5years

29
Q

What are lab prognostic indicators for relapse in BP?

A

High BP180-NC16A ELISA score (>27 U/ml) and to a lesser degree + DIF findings at the cessation of therapy are both good indicators of future relapse.

30
Q

Epidemiology for mucus membrane pemphigoid?

A

Rare, dz of elderly (60-80 y/o) F>M, HLA-DQw7 (subtyped HLA-DQB1*0301)

31
Q

Which mucous membrane pemphigoid has an increased risk of cancer?

A

Anti-epiligrin (laminin 332 aka laminin 5 + epiligrin) cicatricial pemphigoid has an increased risk for cancer

32
Q

What is the pathogenesis of mucous membrane pemphigoid?

A

IgG antibodies against various antigens in anchoring filament zone (vs the hemidesmosome plaque in conventional BP)

[rarely, NC16A antibodies have been detectable in MMP]

33
Q

Pathogenesis of ocular disease in MMP?

A

Increased expression of collagen-binding heat shock protein 47 (HSP47) and TGF-B1 by conjunctival fibroblasts may lead to conjunctival scarring

34
Q

Drugs associated with Drug-induced MMP?

A

Thiol-containing: captopril, gold, thiosulfate, d-penicillamine,

  • NSAIDs (indomethacin)
  • Topical glaucoma solutions (b-blockers practolol)
  • Clonidine
  • Sulfadoxine
35
Q

Clinical of mucous membrane pemphigoid?

A
  • Chronic, autoimmune subepithelial blistering dz characterized by predominant involvement of the external mucosal surfaces and a tendency for scarring
  • Key here is that MMP really is a clinical disease phenotype that is caused by a number of underlying diseases.
  • The scarring of the conjunctival can lead to blindness.
36
Q

What are the 4 subtypes of Mucous Membrane Pemphigoid (MMP)?

A

1. Anti-epiligrin cicatricial pemphigoid: Target- Laminin 332 (aka Laminin 5), clinically indistinguishable from other subtypes, circulating IgG autoAbs that bind to the dermal side of salt-split skin

2. Ocular MMP: purely or predominantly ocular dz, β4 subunit of α6β4 integrin, (β4 subunit of α6β4 integrin, a transmembrane hemidesmosomal component that interacts with laminin 5 (332))

3. Anti-BP MMP: IgG antibodies against BP180 (specifically the distal C-terminal portion), which extends into the lamina densa region

4. Variable Mucosal Involvement +/- skin: unclear antigen-antibody association

37
Q

What are the most common areas affected by mucous membrane pemphigoid?

A

Oral and conjunctival involvement is most common (85% w/ oral involvement)

  • Can also involve the nasopharyngeal area, pharyngeal, largyngeal, and esophageal surfaces
  • Genital/anal mucosal invovlements is rare
38
Q

In what percentage of patients with MMP is there skin involvement?

A

25-30% of cases. Most commonly on the scalp, face, neck, upper trunk.

  • Usually, erythematous plaques becoming sites for recurrent blister formation and erosions w/ atrophic scarring. Usually limited but can become BP-like
  • Involvement of the scalp can cause scarring alopecia
39
Q

What is entropion vs ectropion?

A

In entropion, the eyelid (usually lower lid) folds inward. This causes a problem as the lashes rub against the cornea.

In ectropion it is the opposite, the lid is folded outwards causing problems with dryness, irritation, inflammation

40
Q

What is symblepharon?

A

This is partial or complete adhesion of the palpebral conjunctiva of the eyelid to the bulbar conjunctiva of the eyeball.

41
Q

Tx for mucous membrane pemphigoid?

A
  • If mild/moderate oropharyngeal + cutaneous dz = dapsone (1st line)
  • In severe dz = cyclophosphamide + systemic steroid or steroid-sparing immunosuppressive MMF or azathioprine

surgical correction of ocular scarring may only be attempted AFTER disease is controlled.

42
Q

What is the Brusting-Perry variant of MMP?

A

Skin lesions limited to head and neck, w/ minimal or absent mucosal involvement.

43
Q

What percentage of patients have circulating antibodies detectable by IIF?

A

20-30%

44
Q

What is the histology of mucous membrane pemphigoid?

A

H&E: subepidermal blister formation of mixed infiltrate of variable intensity primarily of mononuclear cells, older lesions w/ fibrosis in the upper dermis

Electron microscopy: DE cleavage within the lamina lucida; advanced conjunctival lesions w/ scarring, lamina densa appears discontinuous, focally thickened or duplicated

45
Q

Epidemiology of Epidermolysis Bullosa Acquisita

A

Rare, estimated incidence 0.25 per million, affects adults and children, adults more commonly, may be more common among Korean/Asian populations as well as African Americans

46
Q

Associations w/ EBA?

A

HLA DRB1*1501 and DR5 in Caucasians and African-Americans or DRB1*13 in Koreans, reports of IBD (MC, particularly Crohns), multiple myeloma, SLE, RA, thyroiditis, DM

47
Q

Pathogenesis of EBA?

A

Antibodies targeting collagen VII (component of anchoring fibrils in sublamina densa). (specifically the non-collagenous domain, NC1)

48
Q

What are the main presentations of EBA?

A

Mechanobullous: non-inflammatory bullae on acral/trauma prone sites, may result in mutilating “mitten” deformity, syndactyly, nail dystrophy and nail loss. Bullous lesions heal with atrophic scars, milia, and dyspigmentation. Scalp lesions w/ scarring alopecia in 20% of cases

Inflammatory “BP-like”: clinically cannot distinguish from BP, heals without milia or atrophic scars, mimics MMP-like presentation

Other inflammatory subtypes: a Brunsting–Perry cicatricial pemphigoid-like presentation with scarring alopecia and a linear IgA bullous dermatosis-like presentation with a polymorphous bullous eruption and a linear band of IgA deposits along the BMZ.

49
Q

Histology/pathology of EBA?

A

H&E: subepidermal blister, cell poor

BP-like or MMP-like: subepidermal blister w/ mixed neuts, eos, lymphs, peri-vascular and dermal fibrosis, festooning of dermal papillae, milia, follicular involvement

50
Q

Treatment for EBA?

A

Systemic corticosteroids and standard immunosuppressive agents, such as azathioprine, methotrexate, mycophenolate mofetil and cyclophosphamide, are sometimes helpful in controlling the BP-like variant of EBA, which may go into remission. Colchicine, dapsone, gold, IVIg and cyclosporine

51
Q

What is the relationship of IgE with BP?

A

IgE a/w early urticarial phase of BP and IgE autoantibodies to type XVII collagen (BPAG2) have been detected

52
Q

Does serum BPAG1 and BPAG2 antibody levels correlate with disease activity?

A

Yes! this does correlate with activity, but the IIF does not (unlike in PV)

53
Q

Describe N vs U serration on DIF and what it means.

A

The U-serration represents linear immunodepositions along the BMZ because they are in the upstanding arms (grass) of the sublamina densa zone between the root-lets of basal keratinocytes (imagine that these immunostains always head towards the lamina lucida)

In the other types of subepidermal autoimmune blistering diseases, the deposits are in the lamina lucida or above so the deposits follow the rootlets of the basal keratinocytes which creates the n-serration pattern (they go down)

54
Q

What medications can induce cicatricial pemphigoid?

A

Clonidine, sulfa drugs, thiol-containing drugs

55
Q

What is the clinical presentation of oral mucous membrane pemphigoid?

A

Lesions in the mouth are often on the gingiva, buccal mucosa, and palate. Alveolar ridges, tongue, and lips are less commonly affected. When on the tongue usually localized to lateral and ventral surfaces

Can have an erosive appearance

56
Q

What is the clinical presentation of the ocular mucous membrane pemphigoid?

A

Can start unilaterally but will often spread to be bilateral. Presents as non-specific chronic conjunctivitis with burning, soreness, foreign-body sensation and mucus production. Then it progresses to subepithelial conjunctival fibrosis, and the scarring shortens the fornices and symblepharon formation occurs (adhesion between bulbar and palpebral conjunctival surfaces), can also lead to trichiasis (inwardly angled eyelashes) and entropion.

57
Q

What is the clinical presentation of pharyngeal/laryngeal/esophageal dz?

A

Can cause scaring and wounds to all of these areas. Ask about voice hoarseness, coughing, difficulty swallowing etc. Caution as chronic inflammation can cause strictures and stenosis in these areas

58
Q

What is the DIF for mucous membrane pemphigoid?

A

DIF: continuous, fine, linear deposits of IgG, IgA, and/or C3 along BMZ, more positive in the mucosa (50–90%) than skin (20-50%), IgG4 and IgG1 subclasses MC of IgG, linear IgA, and M less common

Salt-split: not as helpful, can bind to epidermal or dermal, most MMP Abs bind epidermal roof, except anti-laminin 5 (332) CP w/ IgG Abs that bind dermal side

59
Q

What are the immunochemical serology studies that can be done in mucous membrane pemphigoid?

A

Immunochemical studies: Circulating autoantibodies react with various proteins located w/in BMZ, e.g. laminin 5 (332), BP180 (c-terminal)

60
Q

How often are mucosal lesions seen in EBA?

A

Mucous membranes are involved in 50% of cases. Intact vesicles may be seen in the mouth, larynx, and esophagus, leads to dysphagia, laryngeal stenosis, ocular involvement can lead to blindness like ocular MMP

61
Q

What is the DIF/IIF of EBA?

A
  • DIF: broad linear IgG (> linear C3); u-serrated pattern along BMZ
  • Pattern is opposite of BP (linear C3> linear IgG > n-serrated)
  • Salt-split: linear IgG adhering to the base “floor” of the blister
  • IIF: circulating anti-BMZ antibodies can be detected in approximately half of the patients with EBA