A girl aged 13 months with no history of interest presented with 2 blackish cutaneous lesions with a purplish halo in the first and second toe of the right foot, in addition to a vesicle in the second toe (Fig. 1), which the family believed to be related to contact with a beetle found in the shoe of the patient. She was haemodynamically stable, without vascular or neurologic manifestations or other cutaneous lesions.

Figure 1.

Pigmentation caused by contact with a beetle of the Coleoptera family, from the day of presentation (A) to resolution a few weeks later (D). Blackish stain with well-defined borders in the first and second toes, with a vesicle in the second toe (A).

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The observed lesions were consistent with those caused by the Blaps lusitanica beetle, of the Coleoptera order and Tenebrionidae family. On account of the limited experience with this type of lesion and the presence of a blister, the patient was discharged home with a prescription for a 1-week course of oral amoxicillin-clavulanic acid, and the pigmentation resolved within 2 weeks.

Similar cases have been described in the Mediterranean region.1–3 When threatened, the beetle secretes a dark and malodorous substance rich in carbohydrates and quinines. It usually only stains the skin, and in some instances also causes blisters or dermatitis. The differential diagnosis of acral purpuric skin lesions in children includes traumatic haemorrhage under the stratum corneum, vasospasm, as seen in Raynaud disease or other connective tissue diseases, Janeway lesions characteristic of bacterial endocarditis, cryoglobulinaemia, thromboangiitis obliterans, or acral melanoma. A detailed history-taking and exhaustive physical examination are essential to identify the insect as the cause and avoid performance of additional diagnostic tests.