Dermoscopic Presentation of a Fulminant Rosacea-like Variant of Demodicidosis

Dear Editor,

Demodex folliculorum is a saprophyte acarid that is usually harmless; however, it may induce local inflammation when the mites are present in excessive numbers in the pilosebaceous follicles or when it penetrates into the dermis,[1] also infestation by Demodex can be associated with systemic or topical steroid-induced immunosuppression.[2,3,4] The clinical manifestations of demodicidosis vary from rosacea-like erythema, pustular folliculitis, papulopustular eruptions, granulomatous rosacea-like demodicidosis,[1,3,5] and fulminant rosacea-like presentation that was reported in association with acquired immunodeficiency syndrome in one publication.[6]

A 44-year-old man, with a history of pulmonary tuberculosis 6 months before the dermatological consultation for which he had taken the World Health Organization–recommended antituberculosis regimen, presented slightly pruritic facial lesions weeks after the beginning of the tuberculosis treatment. The physical examination revealed numerous erythematous, confluent dome-shaped papules, and nodules with yellowish and hemorrhagic crusts on a background of thick erythematous rough skin on both the lateral parts of the cheeks and the temporal area [Figure 1]. Polarized-light dermoscopy showed dilated follicular openings, comedones with Demodex agglomerates, and Demodex tails on a background of erythema and crusts; no reticular or polygonal vessels were noticed [Figure 2].

Figure 1.

Inflammatory variant of demodicidosis. Clinical picture: Numerous erythematous, confluent dome-shaped papules, and nodules with yellowish and hemorrhagic crusts on a background of thick erythematous rough skin on both the lateral parts of the cheeks and the temporal area

Figure 2.

Inflammatory variant of demodicidosis. Dermoscopy: dilated follicular openings (yellow arrows), comedones with Demodex agglomerates (red arrows), and Demodex tails (white arrows) on a background of erythema and crusts

A skin biopsy showed a massive presence of Demodex in the follicular openings and a mixed dense inflammatory dermatitis containing histiocytes, lymphocytes, multinucleate giant cells, and plasma cells that attacked hair follicles, with the presence of the mite remnants in the dermis that were surrounded by an intense inflammatory infiltrate [Figure 3]. This atypical pathology presentation was first diagnosed as cutaneous leishmaniasis; however, after a review by two other experienced pathologists in dermatopathology and a clinical-dermoscopy -pathology correlation, the diagnosis of demodicidosis was then confirmed. No clinical or paraclinical signs of immunosuppression were found. The patient was treated successfully with topical metronidazole twice a day and doxycycline 200 mg per day for 3 months; this led to a progressive and complete improvement of the condition [Figure 4].

Figure 3.

Inflammatory variant of demodicidosis. Pathology (hematoxylin and eosin with Giemsa staining): Massive presence of demodex in the follicular openings, and a mixed dense inflammatory dermatitis containing histiocytes, lymphocytes, multinucleate giant cells and plasma cells that attacked hair follicles, with the presence of the mite remnants in the dermis that were surrounded by an intense inflammatory infiltrate

Figure 4.

Inflammatory variant of demodicidosis. After treatment evolution: a complete improvement of the condition

There are various clinical presentations of facial dermatoses induced by Demodex. An intense inflammatory variant of demodicidosis would be explained in this patient by the dense inflammatory infiltrate due to the presence of Demodex mites in the dermis, as it was previously illustrated in the case of Hoekzema et al.,[6] the added value in this case in comparison with the previous one is dermoscopy which may be an important guide for the correct diagnosis in atypical cases.

The two reported specific dermoscopic signs of demodicidosis are “Demodex tails” and “Demodex follicular openings”; the Demodex ‘‘tail’’ indicated the presence of the parasite protruding from the follicular orifice, it appeared as a whitish creamy thread of 1-3 mm in length, the second dermoscopic feature is dilated follicular openings surrounded by an erythematous halo and containing amorphic, grayish-light brown plugs.[7]

In this case, dermoscopy showed an exaggeration of the dermoscopic signs previously reported, Demodex agglomerates inside the follicular openings was described as gelatinous yellow-white prominent structures, in addition to the classic Demodex tails, dilated follicular openings on background of erythema and yellowish and hemorrhagic crusts.

This observation described a rare inflammatory variant of demodicidosis and highlighted the utility of the correlation between dermoscopy and histopathology, especially when the clinical appearance and history are not in favor of the diagnosis.

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