Argas reflexus dermatitis and nocturnal pruritus.

A 71 year-old woman, with no history of atopic dermatitis or allergy, presented to the dermatology clinic with diffuse nocturnal pruritus. She reported that her attic had been invaded by pigeons and was currently under restoration by a cleanup service and had noticed some dust and dirt coming down from the attic. On clinical examination, small isolated erythematous papules on legs, arms, back and abdomen were noticed (Fig. 1). There was no evidence of Sarcoptes scabiei invasion by dermoscopy. The patient brought in a sample of the microscopic dust collected at her home. The analysis of this sample revealed the presence of parasites identified as Argas reflexus (Fig. 2) including a blood-engorged living specimen of 5 mm (Fig. 3), leading to the diagnosis of Argas reflexus dermatitis.

Fig. 1

Small isolated papules on legs.

Fig. 2

Argas reflexus.

Fig. 3

Blood-engorged Argas reflexus.

Argas reflexus is a feral pigeon tick. It is a hematophagous parasite that feeds on pigeons but can use human as a substitute host when pigeon’s density is low or when they are not present [1]. It has a long life span (around 10 years) and can survive without feeding for 3 to 5 years [1,2]. An A.reflexus bite can cause allergic reactions ranging from local manifestations such as itching, erythema and edema, as in our patient, to severe IgE mediated systemic reactions. Ticks are more active during nighttime explaining nocturnal symptoms of the patient. Several cases of nocturnal anaphylactic shock have been described in the literature [2]. The diagnosis is based on anamnesis with presence of pigeons in the environment, identification of the tick, and if available detection of specific IgE to Argas major allergen (Arg r1) [3]. The therapy is based on extermination of the parasite by adequate eradication mesures.

Conflict of interest

Authors have no conflict of interest.

Authorship statement

Authors certify that they have participated equally in this work (conception, writing and editing of the manuscript).