A healthy, 2-month-old, full-term male infant presented with diffuse periungual hyperpigmentation on the fingers that had appeared 1 month earlier. The infant’s mother reported that she had not experienced any episodes of inflammation or scratching during pregnancy, nor had she been treated with any drugs. The infant had no lesions on the feet or the oral or genital mucosa. He was diagnosed with hyperpigmentation of the distal phalanges. No treatment was administered and the benign and transitory nature of this condition was explained to the family (Fig. 1).

Figure 1.

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Hyperpigmentation of the distal phalanges in newborns is a transient benign dermatosis of childhood that is common in black, but not white, children. It consists of periungual hyperpigmentation of the fingers and, occasionally, the toes, in the absence of other diseases. It usually appears between 2 and 6 months of age in full-term newborns and disappears between 1 and 2 years of age, although in some cases it can persist longer.

The pigmentation is enhanced under a Wood lamp, suggesting involvement of the most superficial layers of the skin. Histology shows an increase in the amount of melanin, but no increase in the number of melanocytes. There has been some speculation about a role of maternal hormones in this condition, although the reason why this particular location is affected is unknown.

Given the scarce literature on this condition, it is important to be familiar with this entity to ensure conservative management and reassure parents.