Question
The given lesion is seen on 3 different occasions on the same site. What is the diagnosis?
| A. |
Cutaneous mastocytosis
|
| B. |
Fixed drug eruption
|
| C. |
HSV1
|
| D. |
Erythema multiforme
|
Show Answer
|
Correct Answer � B
Explanation
|
|
Image Interpretation:
– Lesion is solitary, well-circumscribed, erythematous with a dusky violaceous center.
– Shows post-inflammatory hyperpigmentation.
– Classic for *fixed drug eruption* (FDE).
Clinical Features Supporting Fixed Drug Eruption:
– Recurs at the same site on re-exposure to the same drug.
– Sharply demarcated, round/oval, violaceous plaques.
– Common drugs: NSAIDs, sulfonamides, antiepileptics.
– Heals with hyperpigmentation.
Why Other Options Are Incorrect:
– Cutaneous mastocytosis: Usually in children; lesions urticarial or pigmented with Darier’s sign; no fixed recurrence with drugs.
– HSV-1: Causes grouped vesicular lesions on erythematous base, especially face; recurrent but not drug-related or fixed to one site.
– Erythema multiforme: Target lesions with three zones, affects palms/soles/mucosa; linked to infections (e.g. HSV), not fixed to one site.
