Lesions caused by foreign bodies are frequent in paediatrics. Exceptionally, a hair may be embedded under the skin, which is known as cutaneous pili migrans (CPM).1

A girl aged 3 years was referred due to suspicion of cutaneous larva migrans. She felt discomfort in the sole of the foot with onset 1 week prior, and there was a black, thread-like structure in the right foot that appeared to move. The patient had a filiform subcutaneous lesion, black in colour and 3.5 cm long in the medial edge of the sole (Figs. 1 and 2). The physical examination concluded with a diagnosis of CPM. The parents agreed to a watchful waiting approach.

Figure 1.

Linear, filiform and painless foreign body.

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Figure 2.

Magnification revealing a structure with the characteristics of hair.

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Since it was first described in 1957, fewer than 15 cases of CPM have been reported in children.1–3 Although its aetiology is not well understood, it is believed that the hair burrows into the skin through existing cracks in the epidermis or due to friction during walking in children who walk barefoot, as was the case of our patient. This would explain why the soles of the feet are most frequently involved and the migration of the hair. It is usually asymptomatic, contrary to cutaneous larva migrans, which manifests with intense itching and appears as a serpiginous, tortuous lesion (Fig. 3), as opposed to the linear appearance of CPM.2,3

Figure 3.

Illustration of the creeping and tortuous lesion characteristic of cutaneous larva migrans.

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