Background

Granulomatous rosacea (GR) is a rare chronic inflammatory skin disease reported primarily in middle-aged women [1]. It is thought to be a particular form of rosacea on the basis of unique clinical and histological findings of granulomas; it is characterized by erythematous papules most commonly affecting the face; and it tends to have a chronic course [2]. We present the case of a 54-year-old man with a 3-month history of GR associated with demodecidosis.

Case presentation

A 54-year-old Moroccan man with a history of psoriasis in remission presented with a 3-month history of erythematous nonpruritic lesions of the face with hypersensitivity to heat. A clinical examination revealed erythematous, telangiectatic, confluent papules of the lateral side around the eyes without any scales, crusts, or pustules. In the differential diagnosis, we included GR, sarcoidosis, lupus vulgaris, and lupus erythematosus tumidus. Dermoscopy revealed linear vessels characteristically arranged in a polygonal network, creamy and whitish linear areas, and white grayish plugs surrounded by an erythematous halo filling the follicular openings (Fig. 1).

Fig. 1
figure 1

Granulomatous rosacea. Dermoscopy reveals follicular openings containing white grayish plugs (Demodex follicular openings) (blue arrows), creamy whitish linear structures filling the follicular openings (Demodex tails) (red rectangle), and polygonal vessels (blue circles)

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Histological examination of a punch biopsy specimen of the lesion showed granulomatous dermatitis with the presence of Demodex folliculorum on the biopsied tissue. These clinical, dermoscopic, and histological findings were consistent with the diagnosis of GR (Fig. 2), and the patient was treated with topical metronidazole for a total of 10 weeks, which led to a significant improvement.

Fig. 2
figure 2

Granulomatous rosacea. Histological findings (hematoxylin and eosin stain, original magnification × 10) were granulomatous inflammatory infiltrates destroying the hair follicles with the presence of Demodex folliculorum at the follicular ostium

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Discussion

The role of Demodex in GR’s pathogenesis was debated in the last decade, with recent data highlighting its significant role in triggering GR [3]. Our observation confirmed that this mite plays an important role in stimulation of the immune system and the formation of granulomas in GR in unusual sites. In our patient, the presence of Demodex in the follicular openings was confirmed by histology, and we noticed that a granulomatous infiltrate was agglomerated around the pilosebaceous follicles containing the mite. Dermoscopy confirms the presence of the characteristic vascular polygons, not only in conventional rosacea [4, 5] but also in GR. In our patient, we also noticed the most indicative dermoscopic whitish features of demodicidosis, called Demodex tails and Demodex follicular openings [6, 7].

Conclusions

We report an original observation of GR with a rare localization and an association with demodicidosis.