Rosacea-like demodicosis mimicking cutaneous lymphoma

The Pathogenic Role of Demodex Mites in Rosacea: A Potential Therapeutic Target Already in Erythematotelangiectatic Rosacea?

Rosacea is a common facial dermatosis but its definition and classification are still unclear, especially in terms of its links with demodicosis. Triggers of rosacea (ultraviolet light, heat, spicy foods, alcohol, stress, microbes) are currently considered to induce a cascading innate and then adaptive immune response that gets out of control. Recent histological and biochemical studies support the concept that this inflammatory response is a continuum, already present from the onset of the disease, even when no clinical signs of inflammation are visible. The Demodex mite is beginning to be accepted as one of the triggers of this inflammatory cascade, and its proliferation as a marker of rosacea; moreover, the papulopustules of rosacea can be effectively treated with topical acaricidal agents. Demodex proliferation appears to be a continuum process in rosacea, and may not be clinically visible at the onset of the disease. Molecular studies suggest that Demodex may induce tolerogenic dendritic cells and collaborate with vascular endothelial growth factor (VEGF) to induce T cell exhaustion and favor its own proliferation. These interactions among VEGF, Demodex, and immunity need to be explored further and the nosology of rosacea adapted accordingly. However, treating early rosacea, with only clinically visible vascular symptoms, with an acaricide may decrease early inflammation, limit potential flare-ups following laser treatment, and prevent the ultimate development of the papulopustules of rosacea. The effectiveness of this approach needs to be confirmed by prospective controlled clinical trials with long-term follow-up. Currently, the evidence suggests that patients with only vascular symptoms of rosacea should be carefully examined for the presence of follicular scales as signs of Demodex overgrowth or pityriasis folliculorum so that these patients, at least, can be treated early with an acaricidal cream.

Unilateral Demodicidosis of Face Mimicking Hansens Disease

Demodicosis is a common parasitic infection of the hair follicles and the pilosebaceous unit by the Demodex mites viz. Demodex folliculorum and Demodex brevis. Infection by this parasite is common among immunocompromised and elderly. We report a case of facial Demodicosis which presented like atypical rosacea with a gradually progressing swelling and redness on right side of face which was initially diagnosed as a case of Hansen’s disease. Skin biopsy revealed follicular dilatation with presence of Demodex mite along with intense perifollicular lymphomononuclear infiltrate. Patient was treated with oral tab Ivermectin 12 mg stat along with topical gel metronidazole twice daily to which he responded favourably.

[Primary human demodicosis. A disease sui generis]

Human Demodex mites (Demodex folliculorum and Demodex brevis) are unique in that they are an obligate human ectoparasite that can inhabit the pilosebaceous unit lifelong without causing obvious host immune response in most cases. The mode of symbiosis between humans and human Demodex mites is unclear, while the pathogenicity of human Demodex mites in many inflammatory skin diseases is now better understood. Primary human demodicosis is a skin disease sui generis not associated with local or systemic immunosuppression. Diagnosis is often underestimated and differentiation from folliculitis, papulopustular rosacea and perioral dermatitis is not always straightforward. Dependent on the morphology and degree of inflammation, the clinical manifestations can be classified into spinulate, papulopustular, nodulocystic, crustic and fulminant demodicosis. Therapy success can be achieved only with acaricides/arachidicides. The effective doses, optimal regimen and antimicrobial resistance remain to be determined.

Acneiform eruptions

Is it acne or is it not? When this question arises, we can presume that we have crossed the boundaries of "acneiform eruptions" of the face. Although acne may be considered a condition fairly easy to diagnose, it is not rare for the practicing dermatologist or the general physician to wonder when faced with an acneiform eruption before establishing a diagnosis. In this review, we address facial acneiform eruptions in children and in adults, including perioral dermatitis, granulomatous periorificial dermatitis, nevus comedonicus, acne cosmetica, rosacea, demodicosis, folliculitis, acneiform presentation of cutaneous lymphomas, and drug-induced [epidermal growth factor receptor (EGFR) inhibitors, steroids, etc.] acneiform eruptions, along with their diagnosis and therapeutic approaches. The major distinguishing factor in acneiform eruptions is that, in contrast to acne, there are no comedones (whiteheads or blackheads).