A 6-month-old Caucasian boy of normal weight and stature was assessed for congenital hyperpigmentation of the hands and feet, which had been present since birth and, according to the parents, had gradually disappeared.

The dermatologic examination revealed clearly demarcated brownish pigmentation located between the proximal periungual fold and the distal interphalangeal joint of all fingers (Fig. 1). The patient presented no Hutchinson sign, nail alterations, or hyperpigmentation in other locations.

Figure 1

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Based on these clinical findings, a diagnosis of hyperpigmentation of the distal phalanges in infants was made.

This abnormality is a physiological pigmentation that is considered a transitory dermatosis of the newborn infant. It is more common in newborns with constitutively more pigmented skin. It tends to manifest between the ages of 2 and 6 months and affects the distal phalanges of the hands and, sometimes, the feet. It is accentuated by a Wood lamp. Its intensity gradually decreases until complete disappearance at around the age of 1 year. Histology reveals increased melanin but with no increase in the number of melanocytes.

Awareness of this entity makes it possible to reassure parents and avoid invasive or unnecessary treatments, given its benign and self-limiting nature.