An infant brought from a hot, humid region has crops of tiny, thin-walled, non-inflammatory clear vesicles resembling dewdrops over the forehead and neck. The vesicles rupture easily and leave no trace. The level of sweat duct obstruction in this condition is:

• A Dermoepidermal junction
• B Mid-epidermis within the spinous layer
• C Stratum corneum ✓
• D Deep dermis at the eccrine coil

Explanation

The picture is miliaria crystallina, caused by obstruction of the eccrine duct within or just beneath the stratum corneum, producing superficial non-inflammatory vesicles. Obstruction at the deeper intraepidermal level causes miliaria rubra with erythematous pruritic papules, and obstruction at the dermoepidermal junction causes miliaria profunda with flesh-coloured deep papules in recurrent cases. Recognising the depth explains the differing clinical morphology and is a classic examination point.

Reference: Rook's Textbook of Dermatology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.