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.

Localized seborrhoeic dermatitis with hyperhidrosis due to mite infestation in an Iranian cross-breed ram.

A 3-years-old Iranian cross-breed ram with history of repeated local sweating, severe pruritus of body surface was referred to the veterinary clinic. On clinical examination wetness, warmness, pruritus and thickness of affected area were observed. In affected area, hair coat was staring and draggy. Body temperature, heart and respiratory rates were 40.4 degrees C, 120 beat min(-1) and 40 min(-1), respectively. Hematologic indices including packed cell volume, total and differential white blood cell (WBC) and total red blood cell (RBC) were normal. Laboratory examinations of skin scrapings confirmed infestation with Psoroptes ovis. Histopathologic findings included dilation of sweat glands, hyperplasia of sebaceous glands, hyperkeratosis, ulcer and scab formation and eosinophilic dermatitis. History and clinical findings association with the skin scraping and histopathologic findings indicated localized seborrhoeic dermatitis with hyperhidrosis. After treatment with ivermectin at the dose rate of 0.2 mg kg(-1), all clinical signs subsided. This confirmed that the cause of seborrhic dermatitis and hyperhidrosis was mite infestation and other possible causes were ruled out. So this is the first report of localized seborrhoeic dermatitis with hyperhidrosis due to mite infestation in animals.

Is Demodex folliculorum an aetiological factor in seborrhoeic dermatitis?

BACKGROUND: Seborrhoeic dermatitis (SD) is a common inflammatory skin disease for which no single cause has been found, although many factors have been implicated. The mite Demodex folliculorum (DF) is most commonly seen in the pilosebaceous unit in humans. SD is located in areas that are rich in sebaceous glands, which are also preferred by DF. AIMS: To compare the number of DF parasites in patients with clinical SD and in healthy controls, and to investigate any possible relationship between the number of DF mites and the presence of SD. METHODS: The study comprised 38 patients with SD and 38 healthy controls. Standard random and lesion-specific sampling was performed in the group of patients with SD, whereas standard random sampling only was performed for controls. RESULTS: Demodex folliculorum sampling was positive in 19 patients (50%) and 5 controls (13.1%). Mean DF density was 8.16 +/- 10.1/cm(2) (range 0-40) and 1.03 +/- 2.17/cm(2) (1-7) in patient and control groups, respectively. The differences between groups for DF positivity and mean DF density were significant (P = 0.001 for each). DF was found in 13 lesional areas in the patient group, but in only 5 areas in the control group (P = 0.031). CONCLUSIONS: The number of DF mites was significantly higher in both lesional and nonlesional areas of patients with SD. This suggests that, when other aetiological causes are excluded, DF may have either direct or indirect role in the aetiology of SD.

Fluorescein dye improves microscopic evaluation and counting of demodex in blepharitis with cylindrical dandruff.

PURPOSE: To show whether fluorescein dye helps detect and count Demodex embedded in cylindrical dandruff (CD) of epilated eyelashes from patients with blepharitis. METHODS: Two eyelashes with CD were removed from each lid of 10 consecutive patients with blepharitis and subjected to microscopic examination with and without fluorescein solution to detect and count Demodex mites. RESULTS: Of 80 eyelashes examined, 36 (45%) lashes retained their CD after removal. Before addition of the fluorescein solution, the mean total Demodex count per patient was 14.9 +/- 10 and the mean Demodex count per lash was 3.1 +/- 2.5 and 0.8 +/- 0.7 in epilated eyelashes with and without retained CD, respectively (P < 0.0001). After addition of the fluorescein solution, opaque and compact CD instantly expanded to reveal embedded mites in a yellowish and semitransparent background. As a result, the mean total Demodex count per patient was significantly increased to 20.2 +/- 13.8 (P = 0.003), and the mean count per lash was significantly increased to 4.4 +/- 2.8 and 1 +/- 0.8 in eyelashes with and without retained CD (P < 0.0001 and P = 0.007), respectively. This new method yielded more mites in 8 of 10 patients and allowed mites to be detected in 3 lashes with retained CD and 1 lash without retained CD that had an initial count of zero. CONCLUSIONS: Addition of fluorescein solution after mounting further increases the proficiency of detecting and counting mites embedded in CD of epilated eyelashes.

[Some aspects of the skin infestation by Demodex folliculorum]. / Niektóre aspekty zakazenia skóry nuzencem ludzkim.

The importance of demodicids (Demodex folliculorum and D. brevis) infestation and their effect on skin lesions has been described based on literature data and our own clinical and parasitological investigations. Hair follicle mites have been detected in 45% of patients with rosacea, 27% of patients with perioral dermatitis, 28% of patients suffering from seborrhoeic dermatitis and in 3 out of 7 patients with chronic blepharitis. Clinical picture of demodecosis included erythemato-papulous and pustulous (rosacea-like) skin lesions together with erythemato-desquamative changes of the face.

Cutaneous syndrome possibly caused by heartworm infestation in a dog.

A 9-year old German Shepherd bitch was presented with a recent onset of seborrhoea oleosa, hyperpigmentation, erythema, pruritus and alopecia along the neck, thorax, ventrum and the dorsal area of the carpus. The skin changes were believed to be caused by Dirofilaria immitis infection. A combination of topical and parenteral anti-heartworm therapy led to the resolution of the lesions.