Face scabies in the elderly: when dermoscopy can be a game changer

Dear Editor,

Scabies is a common pruritic ectoparasitic infestation of the skin caused by the mite Sarcoptes scabiei. It classically presents as an intensely pruritic eruption that usually involves hands and interdigital folds, wrists, axillae, areolae, abdomen, and genitalia. In immunocompetent adults, mite infestation affecting the face is considered exceptional; accordingly, if topical treatment is chosen, clinicians typically instruct patients to apply the product to the body, excluding the head area.¹ However, elderly individuals, who are particularly vulnerable to scabies and often experience recurrence after topical treatment, may demonstrate atypical presentations, with sparing of the traditional sites but the presence of face and scalp lesions.^1,2 Based on our experience, we speculate that facial scabies in this specific subgroup may be underdiagnosed, thus representing an underestimated cause of recurrence after topical treatment.

We present a case series of three elderly patients (2 females and 1 male, age range 73-86) who had been previously diagnosed with scabies. All patients applied topical permethrin therapy to the skin (excluding the head area) and performed environmental prophylaxis as instructed. After the treatment cycle, clinical examination revealed no lesions at the traditional scabies sites. However, scaly lesions were detected on the nose (in two patients) and ear (in one patient), as shown in Figure 1 a-c. Dermoscopy provided a straightforward diagnosis of scabies, allowing the identification of a “jet with a contrail” sign in all three cases. As represented in Figure 1 d-f, this dermoscopic clue corresponds to the burrow, usually featuring a triangular-shaped structure representing the pigmented anterior part of the mite.³

Dermoscopic examination in the diagnosis of scabies has proven to be a game changer in the detection of this infestation. However, the mite may not always respect the traditional sites: in elderly patients, for example, classic areas may be uninvolved, while the head area may present lesions.² In fact, it has been suggested that topical treatment for the face and scalp or oral ivermectin should be extended in this category of patients as an alternative due to mobility issues.¹ According to the literature, the face and scalp may constitute a reservoir that promotes relapses of scabies.⁴ In this regard, there are also reports of immunocompetent adults with classic scabies who were treated with topical therapies according to the standard protocol (sparing the head area) and subsequently relapsed. A follow-up examination of the scalp revealed burrows, and topical treatment from head to toe led to healing.⁵ Of note, in these reported cases, as well as in our case series, the low mite burden was consistent with the diagnosis of classic scabies, ruling out the crusted scabies variant, in which the head area involvement is much more common due to the very high number of mites.¹

In conclusion, we underline that the face and scalp may represent potential reservoirs for scabies mites. Therefore, it is advisable to extend dermoscopic examination to the head area, especially in elderly or fragile patients. This would ensure appropriate treatment to achieve a complete eradication and prevent recurrences.

Figure 1.

a-c) Face localization of scabies: clinical appearance with scaly and crusted lesions on the nose and ear; d-f) dermoscopy appearance of scabies infestation on the face (nose and ear): “jet with a contrail” sign corresponding to the mite burrow, featuring a triangular-shaped structure (10x magnification).

Availability of data and materials

All data generated or analyzed during this study are included in this published article.