Chapter 30 - Pemphigus

Question 1

What are the 3 major forms of pemphigus?

Answer 1

1) Pemphigus vulgaris, 2) pemphigus foliaceus, 3) paraneoplastic pemphigus. The other forms include 4) drug induced, 5) IgA pemphigus

Question 2

True/False: All pemphigus foliaceus patients will have mucosal membrane erosions.

Answer 2

False. Pemphigus foliaceus patients only have cutaenous involvement without mucosal lesions.

Question 3

What are the 2 major subgroups of cadherins?

Answer 3

Classic and desmosomal, which include desmogleins and desmocollins

Question 4

What are differences between adherens junctions and desmosomes? Hint: what do they anchor, which cadherins do they contain, what are the cytoplasmic components

Answer 4

1) Adherens junctions-anchor actin microfilament bundles, contain classic cadherins, alpha & beta catenin, plakoglobin (quick but weak cellular adhesions); 2) desmosomes-anchor intermediate filaments, contain desmosomal cadherins, plakoglobin, plakophilin, desmoplakin (slow but strong cellular adhesions)

Question 5

What are the 4 isoforms of desmogleins and where are they found?

Answer 5

Dsg1&3-stratified squamous epithelia; Dsg2-all desmosomes including simple epithelia, myocardium; Dsg4-hair follicles

Question 6

Which Ag is cleaved by exfoliative toxins such as those produced by S. aureus?

Answer 6

Dsg1. Leads to bullous impetigo, SSSS

Question 7

What mucosal membrane sites can be involved in PV?

Answer 7

Oral cavity, esophagus, conjunctivae, nasal mucosa, vagina, penis, anus, labia

Question 8

True/False: PV lesions tend not to heal and those that do, heal with hyperpigmentation and scarring.

Answer 8

False, they heal with NO scarring

Question 9

Which drugs are most commonly associated with drug induced pemphigus?

Answer 9

Penicillamine, captopril. Most patients go into remission with discontinuation

Question 10

Which neoplasms are commonly associated with paraneoplastic pemphigus?

Answer 10

Non-Hodgkin lymphoma, chronic lymphocytic leukemia, Castleman’s disease, thymomas, sarcomas, Waldenstrom’s macroglobulinemia

Question 11

What is the most constant clinical feature of paraneoplastic pemphigus?

Answer 11

Stomatitis, which often extend onto vermilion lip. Severe, presents early on, persists and extremely resistant to treatment

Question 12

What test is the most reliable and sensitive diagnostic test for pemphigus?

Answer 12

Direct IF (IgG deposition) on skin bx

Question 13

What is the standard treatment for PV?

Answer 13

Prednisone. Clinical improvement is based on number of new blisters/day, rate of healing. Response in 3-7d

Question 14

What is the drug of choice for IgA pemphigus?

Answer 14

Dapsone. Response in 1-2d

Question 15

What is a good treatment option in localized pemphigus foliaceus?

Answer 15

Potent topical steroids

Question 16

True or false: there are no good treatment guidelines for paraneoplastic pemphigus.

Answer 16

True

Question 17

True or false: continuous cardiac monitoring is necessary with methylprednisone IV administration.

Answer 17

True; this is due to the potential for electrolyte shifts and resultant cardiac arrest

Question 18

True or false: ELISA can distinguish between pemphigus vulgaris that involves only Dsg3 and pemphigus vulgaris that involves both Dsg 1 and Dsg3.

Answer 18

True

Question 19

What type of animal substrate is typically used for indirect IF to detect paraneoplastic pemphigus?

Answer 19

Rat bladder, because it contains transitional epithelium, which will bind antiplakin antibodies

Question 20

What subclass of IgG is most commonly implicated in pemphigus?

Answer 20

IgG4, which does not fix complement

Question 21

True or false: DIF is the most reliable and sensitive diagnostic test for all forms of pemphigus.

Answer 21

True

Question 22

What is the eponymous name for pemphigus erythematosus?

Answer 22

Senear-Usher syndrome

Question 23

True or false: pruritus is often a common symptom associated with IgA pemphigus.

Answer 23

True

Question 24

Roughly what percentage of patients with paraneoplastic pemphigus are already aware of their underlying malignancy?

Answer 24

2/3 (66%)