Do you recognize this condition from your experience with newborns?

Case:Multiple superficial noninflammatory vesicles developed on the upper back of this 13-year-old girl following a sunburn.

Do you recognize this condition from your experience with newborns?

(Answer on next page.)

Miliaria crystallina typically appears in neonates; however, it may follow environmental overheating in older children and teens.

Miliaria crystallina is the result of obstruction of the eccrine duct as it traverses the stratum corneum (horny layer), which produces small subcorneal vesicles. The cause of the obstruction is unknown. The presentation in this girl is typical in teen-agers in that it commonly occurs in fair-skinned, sunburned persons following exercise. It is transient and the vesicles are easily wiped from the skin.

In the newborn period, there are 2 types of miliaria: crystallina and rubra. Miliaria crystallina is common in the first week of life and manifests as multiple noninflammatory vesicles in the folds of the neck and axilla and on covered areas of the trunk. If the eccrine duct obstruction results in leakage of the fluid into the dermis, inflammatory papules and vesicles develop: this condition—miliaria rubra—often develops after the first week of life (Figure). Both conditions are the result of overheating and both resolve spontaneously with external temperature control.