Sir,

Human scabies is an ectoparasitosis caused by Sarcoptes scabiei. Its diagnosis is generally easy in the presence of acute generalized family pruritus with nocturnal exacerbation. Nevertheless, atypical presentations may confuse the clinician [1].

Scabies is a frequent, highly pruritic, and contagious dermatosis. The disease is favored by promiscuity, lack of hygiene, and poverty. It affects males and females of all ages, ethnicities, and socioeconomic levels [1,2].

The clinical signs are typically vesicles, grooves, or nodules on preferential sites: interdigital spaces, anterior surface of the wrists, elbows, axillary hollows, umbilicus, buttocks, mammary areola, and external genitalia. Pruritus is often intense, generalized, and nocturnal [1].

The reference diagnosis is based on direct parasitological examination, which allows Sarcoptes to be visualized under the microscope. However, this examination cannot be performed in routine practice [1].

Herein, we report a clinico-dermoscopic description of atypical scabies.

A 69-year-old patient, with a history of hepatitis B, consulted for intergluteal pruritus evolving for two months. He was treated with a topical antimycotic and dermocorticoid without improvement. The clinical examination revealed several erythematous nodules, rounded, well-limited with regular contours, of firm consistency, mobile to the superficial and deep planes, resting on an erythematous placard excoriated at the intergluteal level (Fig. 1a).

Figure 1: (a) Intergluteal erythema with nodules. (b) Dermoscopy revealing the delta sign and scabious furrows.

A dermoscopic examination revealed scabious furrows, a positive delta sign with an erythematous background, and some fine whitish scales (Fig. 1b).

The patient was treated with Ascabiol with a good evolution, regression of the pruritus, and subsidence of the nodules.

The diagnosis is, therefore, based on the clinical examination in typical forms, confirmed by the dermoscope, which makes it possible to obtain diagnostic certainty and even redirect the diagnosis [3,4], as in the case of our patient.

Scabies is a frequent dermatosis of obvious diagnosis. Atypical forms with particular localizations should not be ignored.

REFERENCES

1. Sunderkötter C, Feldmeier H, Fölster-Holst R, Geisel B, Klinke-Rehbein S, Nast A, et al. S1 guidelines on the diagnosis and treatment of scabies:Short version. J Dtsch Dermatol Ges. 2016;14:1155-67.

2. Adil M, Amin SS, Mohtashim M, Mushtaq S, Qadri S, Varshney I. Erythroderma due to iatrogenic immunosuppression:A case of Norwegian scabies. Our Dermatol Online. 2019;10:53-5.

3. Phan A, Dalle S, Thomas L. [Dermoscopic diagnosis of scabies]. Ann Dermatol Venereol. 2008;135:155-6.

4. Teclessou JN, Lowa PE, Kombate K, Akakpo AS, Saka B, Pitche P. Knowledge, attitudes and practices of non-dermatologist health care personnel regarding scabies in Lomé(Togo). Our Dermatol Online. 2023;14(Supp. 1):6-10.