A 7-year-old child presents with recurrent crops of intensely pruritic, urticarial papules and plaques that leave behind brownish hyperpigmentation. Physical examination reveals Darier sign (whealing upon rubbing a lesion). What is the most likely diagnosis?
- A Atopic dermatitis
- B Lichen planus
- C Urticaria pigmentosa (cutaneous mastocytosis) ✓
- D Fixed drug eruption
Correct answer: C. Urticaria pigmentosa (cutaneous mastocytosis)
Explanation
Urticaria pigmentosa is the most common form of cutaneous mastocytosis in children, presenting with reddish-brown macules and papules that wheal when rubbed (Darier sign). Lesions may blister and leave hyperpigmentation. It is often self-limiting in children. Atopic dermatitis does not show Darier sign. Lichen planus shows purple, polygonal, pruritic papules. Fixed drug eruption recurs at the same site with drug exposure.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.