WBR0476
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| Author | [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D. and Alison Leibowitz [1])]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathophysiology |
| Sub Category | SubCategory::Dermatology |
| Prompt | [[Prompt::A 50-year-old woman presents to her dermatologist with complaints of multiple skin lesions. Physical examination is remarkable for flaccid skin blisters. The upper epidermal layer is easily removed with manual stroking or gentle pressure. Immunofluorescence demonstrates antibodies surrounding the cells in a net-like pattern. Which of the following processes best characterizes the patient's disease?]] |
| Answer A | AnswerA::IgG antibodies against cadherins |
| Answer A Explanation | [[AnswerAExp::Pemphigus vulgaris results from IgG antibodies against demoglein, a member of the cadherin family and a component of desmosomes.]] |
| Answer B | AnswerB::IgM antibodies against desmosomes |
| Answer B Explanation | [[AnswerBExp::Pemphigus vulgaris results from IgG antibodies against desmosomes, not IgM desmosomes.]] |
| Answer C | AnswerC::IgG antibodies against hemidesmosomes |
| Answer C Explanation | [[AnswerCExp::Bullous pemphigoid is an autoimmune disorder that results from IgG auto-antibodies against hemidesmosomes. Unlike pemphigus vulgaris, bullous pemphigoid is not life-threatening. To distinguish both conditions, bullous pemphigoid is characterized by IgG antibodies in the epidermal basement membrane, while PV is characterized by intraepidermal IgG antibodies. Also, immunofluorescence in bullous pemphigoid demonstrates a linear pattern at the epidermal-dermal junction, while it demonstrates a net-like or reticular pattern in pemphigus vulgaris.]] |
| Answer D | AnswerD::IgM antibodies against hemidesmosomes |
| Answer D Explanation | [[AnswerDExp::Pemphigus vulgaris does not result from auto-antibodies against hemidesmosomes. Also, bullous pemphigoid is caused by IgG antibodies against hemidesmosomes, not IgM antibodies.]] |
| Answer E | AnswerE::IgE antibodies against hemidesmosomes |
| Answer E Explanation | AnswerEExp::Pemphigus vulgaris does not result from auto-antibodies against hemidesmosomes. Also, bullous pemphigoid is caused by IgG antibodies against hemidesmosomes, not IgE antibodies. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Pemphigus vulgaris (PV) is a rare, chronic, autoimmune blistering disease of the skin and mucous membranes. The majority of patients who are diagnosed with PV are between the age of 40 and 60 years. It is caused by IgG auto-antibodies against desmoglein of desomosomes (epidermal keratinocyte desmosomal cadherins) and results in flaccid intraepidermal bullae formation and acantholysis, defined as the loss of adhesion between the keratinocytes in the epidermal layer. On physical examination, a positive Nicolsky sign is typically present. Nicolsky sign is the loss of the upper epidermal layer is easily removed with manual stroking or gentle pressure. The diagnosis of PV is made by immunofluorescence that demonstrates antibodies surrounding epidermal cells in a net-like or reticular pattern. Treatment includes systemic corticosteroids and steroid-sparing agents. Educational Objective: Pemphigus vulgaris (PV) is a rare, chronic, autoimmune blistering disease of the skin and mucous membranes. It is caused by IgG auto-antibodies against desmoglein of desomosomes (epidermal keratinocyte desmosomal cadherins) and results in flaccid intraepidermal bullae formation, acantholysis, and a positive Nicolsky sign on physical examination. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Pemphigus vulgaris, WBRKeyword::Pemphigus, WBRKeyword::Bullous, WBRKeyword::Bullae, WBRKeyword::Desmosome, WBRKeyword::Desmoglein, WBRKeyword::Cadherin, WBRKeyword::Keratinocyte, WBRKeyword::Flaccid blisters, WBRKeyword::Skin lesions, WBRKeyword::Nicolsky sign, WBRKeyword::IgG, WBRKeyword::Autoantibodies, WBRKeyword::Antibodies, WBRKeyword::Autoimmune, WBRKeyword::Intraepidermal, WBRKeyword::Acantholysis |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |