Page 524 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

480 section iii Musculoskeletal, skin, and connective tissue ` dERmatology Musculoskeletal, skin, and connective tissue ` dERmatology

Autoimmune blistering skin disorders
Pemphigus vulgaris Bullous pemphigoid
pathophysiology Potentially fatal. Most commonly seen in older Less severe than pemphigus vulgaris. Most
adults. Type II hypersensitivity reaction. commonly seen in older adults. Type II
IgG antibodies against desmoglein-1 and/or hypersensitivity reaction.
desmoglein-3 (component of desmosomes, IgG antibodies against hemidesmosomes
which connect keratinocytes in the stratum (epidermal basement membrane; antibodies
spinosum). are “bullow” the epidermis).
gRoss moRphology Flaccid intraepidermal bullae A caused by Tense blisters C containing eosinophils; oral
acantholysis (separation of keratinocytes, “row mucosa spared. Nikolsky sign ⊝.
of tombstones” on H&E stain); oral mucosa is
involved. Nikolsky sign ⊕.
immUnoFlUoREsCEnCE Reticular pattern around epidermal cells B . Linear pattern at epidermal-dermal junction D.
A B C D

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