We present the case of a female infant aged 1 month followed up for screening of vertical HIV transmission. She had generalised hyperpigmented lines along the abdominal creases (Fig. 1) present from birth, in absence of any other lesions. She received a clinical diagnosis of transient pigmentary lines of the newborn. The lesions faded gradually over the first 4 months of life (Fig. 2).

Figure 1.

Generalised hyperpigmentation along the creases of the abdomen at 1 month post birth.

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Figure 2.

Fading hyperpigmented abdominal creases at 4 months post birth.

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Transient pigmentary lines are infrequent lesions1 in the spectrum of benign transient cutaneous lesions of the newborn.2,3 Most of the described cases occurred in African American male infants.1,3 It has been hypothesised that their aetiology may involve positional mechanical trauma in utero resulting in hyperkeratosis of the skinfolds.1,2 The differential diagnosis includes hyperpigmentation secondary to congenital adrenal hyperplasia.2 There is no known association with underlying disease,1 although it may appear in the context of keratinization or pigmentation disorders.2 These lesions resolve spontaneously within 1 year post birth.1