Infantile acropustulosis is a syndrome characterized by recurrent crops of 1- to 2-mm pruritic vesiculopustules, which appear predominantly on distal extremities of infants. Nine biopsy specimens from six cases of infantile acropustulosis have been studied. We found that necrolysis of keratinocytes is the initial event leading to an inflammatory reaction and to an intraepidermal pustule, which progresses to a subcorneal pustule. These different histologic stages are correlated with clinical features. We found that the pustules may be filled with neutrophils or eosinophils, without particular significance. We have not found a correlation among blood eosinophilia, composition of cutaneous infiltrate, age of infant, and course of eruption.