WBR0769
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Dermatology |
| Prompt | [[Prompt::A 14 year old boy is brought by his mother to the physician's office for pruritic lesions on his skin. The mother informs the physician that the child just recently returned from a picnic and had been exposed to poison ivy plants. On physical examination, the physician notes vesicular bullous lesions with erythema on the lower extremities. The patient's condition is best characterized by a hypersensitivity disorder that resembles which other disease?]] |
| Answer A | AnswerA::Pernicious anemia |
| Answer A Explanation | AnswerAExp::Pernicious anemia is a type II hypersensitivity disorder. |
| Answer B | AnswerB::Multiple sclerosis (MS) |
| Answer B Explanation | AnswerBExp::MS is caused by a type IV hypersensitivity disorder. |
| Answer C | AnswerC::Systemic lupus erythematosus (SLE) |
| Answer C Explanation | AnswerCExp::SLE is caused by a type III hypersensitivity disorder. |
| Answer D | AnswerD::Atopic dermatitis |
| Answer D Explanation | AnswerDExp::Eczema or atopic dermatitis is caused by a type I hypersensitivity disorder. |
| Answer E | AnswerE::Poststreptococcal glomerulonephritis (PSGN) |
| Answer E Explanation | AnswerEExp::PSGN is a caused by a type III hypersensitivity disorder. |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The patient is presenting with contact dermatitis following exposure to poison ivy, a common allergen. Contact dermatitis is caused by a type IV (delayed) hypersensitivity reaction. Similarly, multiple sclerosis is also caused by a type IV hypersensitivity disorder. Other diseases that are also implicated in this type of disorder are: Guillain-Barre syndrome, graft-vs-host disease, and PPD testing for Mycobacterium tuberculosis.
Educational Objective: Contact dermatitis and multiple sclerosis are both caused by a type IV hypersensitivity disorder. |
| Approved | Approved::No |
| Keyword | WBRKeyword::multiple, WBRKeyword::sclerosis, WBRKeyword::type III, WBRKeyword::hypersensitivity, WBRKeyword::disorder, WBRKeyword::type I, WBRKeyword::type II, WBRKeyword::type IV, WBRKeyword::dermatitis, WBRKeyword::contact, WBRKeyword::irritant, WBRKeyword::allergic, WBRKeyword::atopic |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |