Pthirus pubis Linnaeus, 1758 (Diptera: Anoplura), popularly known as crab louse, usually infests the pubis, groin, buttocks, intergluteal fold, and perianal region. However, it can also infest, in particular in hairy males and/or in chronic infestations, the thighs, abdomen, chest, axillae, and face. The involvement of eyelashes and eyebrows is more common in children (1,2). Involvement of the scalp is very rare (3, 4). We report a case of pthiriasis of an ear: to our knowledge, no similar cases have been published in the international literature.
CASE REPORT
A 46-year-old Caucasian man was admitted with a clinical diagnosis of chronic itching. The patient stated that he was in good general health and that he was not on therapy with systemic drugs. He also declared that he had been suffering from widespread itching for about 3 months. He had been unsuccessfully treated at other centres with topical corticosteroids and oral antihistamines.
Dermatological examination revealed the presence of several widespread scratch marks. Furthermore, tens of specimens of Pthirus pubis were located on the pubis, abdomen, chest, and axillae. No other areas, such as the scalp, face, and buttocks, were involved. However, the patient stated that a bothersome itching was present in his right external auditory canal. Otoscopy revealed the presence of two pubic lice (Figs 1–2). The same diagnostic method was negative at the left external auditory canal. Otorhinolaryngological examination revealed no hearing abnormalities. Laboratory examinations were within normal ranges. Bacteriological culture of the skin was negative.
Fig. 1.
Female of Pthirus pubis (dermoscopy image, Heine Delta20 plus).
Fig. 2.
Hypertrichosis of the concha of the patient.
The patient was successfully treated with a foam containing 0.165% pyrethrins and 1.65% piperonyl butoxide (1 application/day for 2 consecutive days), and hydroxyzine (25 mg/day for 2 weeks). The treatment with the foam was repeated 7 days later. Follow up (4 months) was negative.
DISCUSSION
In 1983, Mahzoon et al. (5) published the case of a 33-year-old woman with elephantiasis of the ears associated with chronic pediculosis capitis. In 2017, other Indian authors reported a 44-year-old woman with massive lice involvement of her right external auditory canal. However, in this case, the authors did not specify if the causative agents were head or pubic lice (6). In our patient, it is possible that the involvement of the ear was caused by the long duration of the infestation (3 months), the wrong therapy (topical corticosteroids and oral antihistamines), and the presence of hypertrichosis at the concha of the auricle (Fig. 2). As previously mentioned, we have not found similar cases in the literature.
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