Demodex folliculorum infestations in common facial dermatoses: acne vulgaris, rosacea, seborrheic dermatitis.

BACKGROUND: Demodex mites are found on the skin of many healthy individuals. Demodex mites in high densities are considered to play a pathogenic role. OBJECTIVE: To investigate the association between Demodex infestation and the three most common facial dermatoses: acne vulgaris, rosacea and seborrheic dermatitis. METHODS: This prospective, observational case-control study included 127 patients (43 with acne vulgaris, 43 with rosacea and 41 with seborrheic dermatitis) and 77 healthy controls. The presence of demodicosis was evaluated by standardized skin surface biopsy in both the patient and control groups. RESULTS: In terms of gender and age, no significant difference was found between the patients and controls (p>0.05). Demodex infestation rates were significantly higher in patients than in controls (p=0.001). Demodex infestation rates were significantly higher in the rosacea group than acne vulgaris and seborrheic dermatitis groups and controls (p=0.001; p=0.024; p=0.001, respectively). Demodex infestation was found to be significantly higher in the acne vulgaris and seborrheic dermatitis groups than in controls (p=0.001 and p=0.001, respectively). No difference was observed between the acne vulgaris and seborrheic dermatitis groups in terms of demodicosis (p=0.294). STUDY LIMITATIONS: Small sample size is a limitation of the study. The lack of an objective scoring system in the diagnosis of Demodex infestation is another limitation. CONCLUSION: The findings of the present study emphasize that acne vulgaris, rosacea and seborrheic dermatitis are significantly associated with Demodex infestation. Standardized skin surface biopsy is a practical tool in the determination of Demodex infestation.

Demodex folliculorum infestations in common facial dermatoses: acne vulgaris, rosacea, seborrheic dermatitis

Abstract Background: Demodex mites are found on the skin of many healthy individuals. Demodex mites in high densities are considered to play a pathogenic role. Objective: To investigate the association between Demodex infestation and the three most common facial dermatoses: acne vulgaris, rosacea and seborrheic dermatitis. Methods: This prospective, observational case-control study included 127 patients (43 with acne vulgaris, 43 with rosacea and 41 with seborrheic dermatitis) and 77 healthy controls. The presence of demodicosis was evaluated by standardized skin surface biopsy in both the patient and control groups. Results: In terms of gender and age, no significant difference was found between the patients and controls (p > 0.05). Demodex infestation rates were significantly higher in patients than in controls (p = 0.001). Demodex infestation rates were significantly higher in the rosacea group than acne vulgaris and seborrheic dermatitis groups and controls (p = 0.001; p = 0.024; p = 0.001, respectively). Demodex infestation was found to be significantly higher in the acne vulgaris and seborrheic dermatitis groups than in controls (p = 0.001 and p = 0.001, respectively). No difference was observed between the acne vulgaris and seborrheic dermatitis groups in terms of demodicosis (p = 0.294). Study limitations: Small sample size is a limitation of the study. The lack of an objective scoring system in the diagnosis of Demodex infestation is another limitation. Conclusion: The findings of the present study emphasize that acne vulgaris, rosacea and seborrheic dermatitis are significantly associated with Demodex infestation. Standardized skin surface biopsy is a practical tool in the determination of Demodex infestation.

Demodex and rosacea: Is there a relationship?

PURPOSE: The objective of the study is to compare the frequency of Demodex on the eyelash follicle of patients with rosacea and referents without rosacea or ophthalmological disorders. METHODS: This is a comparative, open, observational, and cross-sectional study that included 41 patients diagnosed with rosacea and 41 referents without rosacea diagnosis or ophthalmic alterations. The individuals underwent a slit-lamp examination in which two eyelashes per eyelid were removed with fine forceps. The presence of Demodex was sought by direct visualization under a light microscope. The results were expressed as "positive" when at least one mite on one lash was found and "negative" when no mite was identified. Chi-square test was used to compare the presence of mites in both groups. RESULTS: Eighty-two study individuals (45 females and 37 males) were included, of which 41 patients were diagnosed with rosacea and 41 were without rosacea or ophthalmic alterations. The average mean age was 37 years with a minimum of 19 and a maximum of 87 years. Of the 41 patients with rosacea, 31 had erythematotelangiectatic rosacea and 10 had papulopustular rosacea. There were no patients with phymatous or ocular rosacea. The presence of Demodex was found in 32 patients: 24 patients with rosacea diagnosis (16 of the erythematotelangiectatic subtype and 8 of papulopustular subtype) and 8 patients without rosacea or ophthalmic alterations (P ≤ 0.001). CONCLUSION: Rosacea was found to be a statistically significant risk factor for Demodex infestation in eyelashes, irrespective of age and sex, with a higher prevalence in papulopustular variety.

Bacillus cereus strain isolated from Demodex folliculorum in patients with topical steroid-induced rosaceiform facial dermatitis.

The aim of the study was to identify Bacillus species from the Demodex folliculorum of patients with topical steroidinduced facial rosaceiform dermatitis. Of the 75 patients examined, 20% had clinical spinulosis, while 18.66% had dermoscopic features of Demodex: follicular plugs and tails. Of the 17.33% positive patients identified upon microscopy for Demodex, samples for bacterial culture were plated on trypticase soy Colombia agar. Identification was performed by microorganisms grown method mass spectrometry. We identified a strain of Bacillus cereus.

Bacillus cereus strain isolated from Demodex folliculorum in patients with topical steroid-induced rosaceiform facial dermatitis

Abstract: The aim of the study was to identify Bacillus species from the Demodex folliculorum of patients with topical steroidinduced facial rosaceiform dermatitis. Of the 75 patients examined, 20% had clinical spinulosis, while 18.66% had dermoscopic features of Demodex: follicular plugs and tails. Of the 17.33% positive patients identified upon microscopy for Demodex, samples for bacterial culture were plated on trypticase soy Colombia agar. Identification was performed by microorganisms grown method mass spectrometry. We identified a strain of Bacillus cereus.

Demodex folliculorum: its association with oily skin surface rather than rosacea lesions.

BACKGROUND: Despite the predilection of Demodex folliculorum (DF) for human sebum, observational studies addressing a relationship between this agent and rosacea paid no attention to the effect of a potentially acting confounder, the oily nature of the skin. OBJECTIVES: To analyze whether a relationship exists between the presence of the mite in rosacea and oily cutis. MATERIALS AND METHODS: An observational study on 63 rosacea cases and 61 healthy controls, both discriminated according to their predominance of oily or dry cutis, was carried out to investigate demodectic density by the skin surface biopsy. RESULTS: While comparisons on the density of DF revealed no differences between patients and controls (Mann-Whitney U-test, P = 0.35), persons with an oily cutis had increased amounts of this mite on the skin surface (Mann-Whitney U-test, P < 0.05), irrespective of whether they had rosacea or not. CONCLUSIONS: The association between DF and oily skin rather than rosacea lesions gives no support for this agent being implied in disease pathogenesis.

Gnatophyma: a rare variant of phyma.

We report a case of a 44-year-old woman with an 8-year history of gnatophyma. Rosacea is a facial dermatosis that may present as flushing, erythema, telangiectases, papules, pustules and phyma. Phyma is considered the final evolution stage of rosacea and is a rare variant. Treatment of phyma with atypical localization may be a challenge for dermatologists in clinical practice.

Demodecidosis: ¿comensalismo o parasitismo? / Demodecidosis: commensalism o parasitism?

Con el objeto de evaluar la importancia que tiene el hallazgo de Demodex sp. en dermatología humana, se realizó el presente estudio de casos y controles, completando con análisis químico del parásito. Los casos presentaban rosácea o eccematide seborreica, mientras que los controles, piel normal. Las muestras fueron extraídas del rostro mediante aplicación de cintas adhesivas transparentes sobre la piel, las que luego se adhirieron a portaobjetos para buscar el artrópodo por microscopía. El hallazgo de un solo parásito fue suficiente como criterio de positividad. Además se realizó análisis espectrofotométrico de los parásitos, por fluorescencia de rayos X. El 36,6 por ciento de los casos presentó Demodex sp. asociado con dermatitis perioral, rosácea, eccematide seborreica y en conducto nasal asociado a Staphylococcus aureus. Solamente en el 3,3 por ciento de los controles se demostró la presencia del parásito. Odds Ratio: 16,79; X²:8,44; p: 0,0036, límite de confianza 95 por ciento. El análisis espectrométrico por fluorescencia de rayos X, demostró presencia de: calcio, titanio, hierro, azufre, fósforo, cobre, níquel, zinc, potasio, cloro, magnesio, aluminio y silicio en los artrópodos, correspondiendo al cobre y al hierro los picos de mayor intensidad. Luego del tratamiento para Demodex sp. se produjo remisión de los cuadros. Se concluye que existe asociación estadísticamente significativa entre las dermatopatías mencionadas y Demodex sp. El cobre y el hierro de los parásitos podrían, eventualmente, contribuir a agravar los cuadros por reacciones alérgicas (AU)

Is demodex really non-pathogenic?

Although usually considered a non-pathogenic parasite in parasitological textbooks, Demodex folliculorum has been implicated as a causative agent for some dermatological conditions, such as rosacea-like eruptions and some types of blepharitis. Several anecdotal reports have demonstrated unequivocal tissue damage directly related to the presence of the parasite. However, this seems to be exceedingly rare, in contrast with the marked prevalence of this infestation. We have had the opportunity to observe one of such cases. A 38-year-old woman presented with rosacea-like papular lesions in her right cheek. Histopathological examination revealed granulomatous dermal inflammation with a well-preserved mite phagocytized by a multinucleated giant cell. This finding may be taken as an evidence for the pathogenicity of the parasite, inasmuch as it does not explain how such a common parasite is able to produce such a rare disease.

Is Demodex really non-pathogenic?

Although usually considered a non-pathogenic parasite in parasitological textbooks, Demodex folliculorum has been implicated as a causative agent for some dermatological conditions, such as rosacea-like eruptions and some types of blepharitis. Several anecdotal reports have demonstrated unequivocal tissue damage directly related to the presence of the parasite. However, this seems to be exceedingly rare, in contrast with the marked prevalence of this infestation. We have had the opportunity to observe one of such cases. A 38-year-old woman presented with rosacea-like papular lesions in her right cheek. Histopathological examination revealed granulomatous dermal inflammation with a well-preserved mite phagocytized by a multinucleated giant cell. This finding may be taken as an evidence for the pathogenicity of the parasite, inasmuch as it does not explain how such a common parasite is able to produce such a rare disease.