Demodex Research Articles

Has the Use of the Mask Exacerbated Rosacea During the Pandemic?

During the COVID-19 pandemic, personal protective equipment, particularly face masks, became an essential requirement to engage in various activities. Several articles reported an increase of recurrences of dermatologic facial diseases (ie, acne, rosacea) related to mask use. To evaluate the number of recurrences of rosacea related to face mask use. This prospective study was conducted on adult patients with a pre-pandemic diagnosis of mild and moderate papulopustular rosacea. All patients had previously achieved either partial or complete remission after a 4-month treatment with topical ivermectin in 2019. We collected data in two different phases characterized by different intensity of mask use during the pandemic and post-pandemic period. We collected data through clinical assessment of the disease, questionnaires on personal habits and standardized skin surface biopsy to study the Demodex mites count. We enrolled a total of 30 patients. In the pandemic period, 5/30 patients had a relapse of mild papulopustular rosacea; the Demodex sample resulted positive in 4/5 relapsed patients. In the post-pandemic period, 4/30 patients reported a relapse of mild rosacea (3 patients) and moderate papulopustular rosacea (1 patient). At the Demodex exam, 1/4 relapsed patients resulted positive. We did not find a significant increase in relapses of papulopustular rosacea during the pandemic. An appropriate anti-parasitic treatment may reduce the number of recurrences due to mask use.

RESEARCH ON THE PREVALENCE, CLINICAL CHARACTERISTICS, AND RELATED FACTORS IN ACNE VULGARIS PATIENTS WITH DEMODEX INFECTION IN CAN THO CITY FROM 2021 TO 2023

Background: Acne is a common disorder, associated with inflammation of the sebaceous and bacterial hair follicle units and has diverse clinical manifestations. The most commonly mentioned causes and factors associated with the onset of acne in adulthood are hormones, antibiotic-resistant bacteria, and the use of drugs and cosmetics. In particular, the increase in the number of Demodex mites due to the habit of using cosmetics of unknown origin, has caused complicated clinical symptoms and difficulties in the treatment of acne today. Objectives: To determine the prevalence, clinical characteristics and some related factors in patients with acne vulgaris superinfected with Demodex. Materials and methods: A cross-sectional descriptive study with analysis was conducted on 154 acne vulgaris patients visiting medical facilities in Can Tho city in 2021-2023. Results: The study included 154 acne vulgaris patients with an average age of 22.16 ± 6.739 years old, with males constituting the majority. Among the patients, 29.87% had Demodex infestation, and 9.74% of them had a Demodex density of 5 or more mites. The majority of acne cases were of moderate or higher severity, with the most severe cases accounting for 85.7% of those with Demodex presence. Clinical features observed in patients with Demodex infestation included closed comedones (97.8%), open comedones (93.5%), papules (63%), pustules (60.9%), and cystic nodules (52.2%). Additionally, 93.5% and 91.3% of patients reported symptoms of peeling skin, but only 50% reported a feeling of ants, which appeared to be related to Demodex infection in acne patients. Furthermore, habits such as sharing towels, makeup, and wearing masks for more than 8 hours were identified as risk factors for Demodex infection. Conclusions: The presence of Demodex in acne patients is associated with a variety of clinical manifestations, including acne accompanied by skin peeling, scaling, and itching sensation. The relationship between Demodex infestation and the sensation of ants requires further investigation. Additionally, papules, pustules, and crawling sensations were also found to be related to Demodex infection. Moreover, certain habits, such as sharing towels, using makeup, and wearing masks for prolonged periods, appear to be risk factors for Demodex infection in acne patients

Cutaneous neurogenic inflammation mediated by TRPV1-NGF-TRKA pathway activation in rosacea is exacerbated by the presence of Demodex mites.

Rosacea is a common chronic inflammatory skin condition that is often refractory to treatment, with frequent relapses. Alterations in the skin immunological response and Demodex mite infestation are the primary aetiologic factors targeted for treatment. Transient receptor potential cation channel subfamily V member 1 (TRPV1) is a nociceptive cation channel that plays a role in cutaneous neurogenic pain and can be activated by various rosacea triggers. We investigated the effects of TRPV1 modulation in rosacea, focussing on Demodex mite colonization and cutaneous neurogenic inflammation. We examined mRNA expression levels according to Demodex population counts. An in vitro study using capsazepine as a TRPV1 antagonist was performed to assess the influence of TRPV1 in keratinocytes. A rosacea-like mouse model was generated by the injection of the 37-amino acid C-terminal cathelicidin peptide (LL37), and changes in the skin, dorsal root ganglion (DRG) and ears were examined. Increased Demodex mite population counts were associated with increased expression levels of TRPV1, tropomyosin receptor kinase A (TrkA) and nerve growth factor (NGF), and these levels could be reduced by capsazepine treatment in keratinocytes. In an in vivo study, the downstream effects of TRPV1 activation were investigated in the skin, DRG and ears of the rosacea-like mouse model. The findings of this study are instrumental for understanding the underlying causes of rosacea and could potentially lead to the development of new treatments targeting the NGF-TrkA-TRPV1 pathway. The identification of this pathway as a therapeutic target could represent a major breakthrough for rosacea research, potentially resulting in more effective and targeted rosacea treatments. This study contributes to an improved understanding of rosacea pathophysiology, which may lead to the development of more effective treatments in the future.

Follicular scales, scalp and ocular involvement in patients with papulopustular rosacea: prevalence and association with Demodex mite proliferation.

Facial follicular scales, dandruff, scalp itching and ocular alterations are lesser-known signs of rosacea and demodicosis. The aim of this prospective original study was to investigate the presence of these signs and symptoms in patients with almost-clear, mild and moderate papulopustular rosacea (PPR) and to study the differences between Demodex-positive (D+) and Demodex-negative (D-) rosacea. Twenty-seven out of 60 patients (45%) presented follicular scales, 24 (40%) ocular involvement and 22 (36.67%) scalp involvement. Follicular scales were more frequently observed in mild and moderate than in almost-clear rosacea (P<0.001). Itching of the scalp was more frequently reported in patients with moderate rosacea than in those with mild disease (P=0.05). Follicular scales (P=0.002) and scalp itching (P=0.05) were more frequently reported in D+ than in D- patients. Among D+ patients, scalp itching was more frequently reported in mild than in almost clear rosacea (P=0.01) and ocular symptoms associated to scalp itching were more frequently reported in moderate than in almost-clear rosacea (P=0.05). We suggest looking for these signs and symptoms in all patients with PPR, because they can be a sign of a more severe form of rosacea or of demod-icosis.

Zihinsel engelli bireylerde Demodex akar (Acari: Demodecidae) prevalansı ve yoğunluğu

This study was conducted to determine the prevalence and intensity of D. folliculorum and D. brevis in mentally disabled individuals receiving care and support services in rehabilitation centers in Erzincan province. The study included 217 mentally disabled participants who were receiving care and support services in 7 separate rehabilitation centers operating in the provincial center of Erzincan. Sample materials were taken from the cheek, nasolabial and chin area of each participant by Standard Superficial Skin Biopsy (SSSB) method and examined for the presence and number of Demodex mites under a light microscope. In the study, D. folliculorum (mean 8.34/cm2) was detected in 58% of mentally disabled people, D. brevis (mean 1.26/cm2) in 25%, and Demodex mites (mean 9.59/cm2) was detected in 61% of the all participants. When the participants were evaluated in terms of Demodex prevalence, it was determined that D. folliculorum was approximately 2.3 times more common than D. brevis. Similarly, when evaluated in terms of the average number of mites per cm2, it was found that D. folliculorum was about 7 times denser than D. brevis. On the other hand, it was determined that the prevalence of Demodex mites increased as the severity of intellectual disabilities increased, while it was found that the intensity of Demodex was highest in participants with moderate mentally disabled. As a result, it was found that D. folliculorum and D. brevis were widespread and intense in both healthy individuals and mentally disabled individuals, as well as in many patient groups. It was thought that the findings obtained in our study might be useful to consider mentally disabled individuals with dermatological complaints during the clinical evaluation process.

The Possible Relation of Demodex and Facial Erythema in Connective Tissue Diseases.

We aimed to investigate the frequency of Demodex infestation and clinical implications in connective tissue disease patients with facial erythema. Patients diagnosed with a connective tissue disease and had facial erythema were consecutively enrolled in the study from 2019-2020. An age and gender matched control group was formed from healthy volunteers. Presence of Demodex was investigated by standardized skin surface biopsy. Number of Demodex mites over 5 per centimeter square was considered meaningful for infestation. Topical or systemic metronidazole treatment was given to the connective tissue disease patients with Demodex infestation. Facial erythema visual analog scale was questioned in patients at treatment onset and one month after. A total of 31 connective tissue disease patients with facial erythema were enrolled. Control group included 31 healthy volunteers. Demographics and comorbidities were similar between groups. Demodex infestation was present in 58.1% of the disease group and in 25.8% of the control group (P=0.01). Pruritus was the most common symptom in patients with infestation. Median (IQR) facial erythema visual analog scale score was 6 (3) at treatment onset and was 2 (2.5) one month later (P<0.001). When evaluating facial cutaneous lesions, Demodex infestation should not be overlooked in a patient group like connective tissue diseases with dysfunctional immune system.

Refining the Diagnostic Technique to Determine Prevalence of Demodex Mites in Eyelash Hair Follicles Within Standard Ophthalmic Practice: A Single-Center Outpatient Clinical Study.

A high density of Demodex infestation in human eyelids and eyelash follicles has been implicated in a variety of ocular surface conditions. However, Demodex infestation often goes undiagnosed and untreated, due to an overlap in signs and symptoms with other sources of ocular surface inflammation. We sought to refine the diagnostic technique for outpatient assessment for Demodex infestation and determine prevalence of Demodex mites in the hair follicles of eyelashes from patients in a standard ophthalmic practice. Patients recruited from a single outpatient ophthalmology clinic were examined for the presence of Demodex mites following standard ophthalmic consultation. During anterior segment biomicroscopic examination, investigators searched for cylindrical dandruff and collarettes around the base of patient eyelashes. These were removed, and individual eyelashes manipulated with tweezers to reveal Demodex mites. Presence of Demodex, cylindrical dandruff and collarettes, time taken to identify the first Demodex mite, mean number of Demodex mites per hair shaft, and patient-reported symptoms of blepharitis were recorded and analyzed to determine potential correlations. A total of 173 patients were recruited, of whom 106 were included in Demodex prevalence analyses. Demodex infestation was identified in 100/106 (94%) patients, with a mean time of 2 minutes and 20 seconds taken to find the first Demodex mite and a mean number of 3 mites identified per hair shaft. Presence of Demodex significantly correlated with the presence of cylindrical dandruff (98/106 [92%] patients; p < 0.001), but not with the presence of collarettes (62/106 [58%] patients; p = 0.230) or symptoms of blepharitis (15/106 [14%] patients; p = 0.591). These results highlight the pervasiveness of Demodex infestation, predicted by the presence of cylindrical dandruff, in the eyelashes of patients in a standard ophthalmic practice. They support the use of a non-invasive diagnostic technique to allow fast, simple identification of Demodex by ophthalmologists and optometrists in outpatient clinical practice.

Demodex Mite Infections: About Two Cases of Demodicosis on Rosacea Associated Respectively with Recurrent Chalazion and Allergic Rhinitis in Dakar, Senegal

Demodex Mite Infections: About Two Cases of Demodicosis on Rosacea Associated Respectively with Recurrent Chalazion and Allergic Rhinitis in Dakar, Senegal

Lotilaner Ophthalmic Solution 0.25% for Demodex Blepharitis: Randomized, Vehicle-Controlled, Multicenter, Phase 3 Trial (Saturn-2)

To evaluate the safety and efficacy of lotilaner ophthalmic solution 0.25% compared with vehicle for the treatment of Demodex blepharitis. Prospective, randomized, double-masked, vehicle-controlled, multicenter, phase 3 clinical trial. Four hundred twelve patients with Demodex blepharitis were assigned randomly in a 1:1 ratio to receive either lotilaner ophthalmic solution 0.25% (study group) or vehicle without lotilaner (control group). Patients with Demodex blepharitis treated at 21 United States clinical sites were assigned either to the study group (n= 203) to receive lotilaner ophthalmic solution 0.25% or to the control group (n= 209) to receive vehicle without lotilaner bilaterally twice daily for 6 weeks. Collarettes and erythema were graded for each eyelid at screening and at all visits after baseline. At screening and on days 15, 22, and 43, 4 or more eyelashes were epilated from each eye, and the number of Demodex mites present on the lashes was counted with a microscope. Mite density was calculated as the number of mites per lash. Outcome measures included collarette cure (collarette grade 0), clinically meaningful collarette reduction to 10 collarettes or fewer (grade 0 or 1), mite eradication (0 mites/lash), erythema cure (grade 0), composite cure (grade 0 for collarettes as well as erythema), compliance with the drop regimen, drop comfort, and adverse events. At day 43, the study group achieved a statistically significant (P < 0.0001) higher proportion of patients with collarette cure (56.0% vs. 12.5%), clinically meaningful collarette reduction to 10 collarettes or fewer (89.1% vs. 33.0%), mite eradication (51.8% vs. 14.6%), erythema cure (31.1% vs. 9.0%), and composite cure (19.2% vs. 4.0%) than the control group. High compliance with the drop regimen (mean ± standard deviation, 98.7 ± 5.3%) in the study group was observed, and 90.7% of patients found the drops to be neutral to very comfortable. Twice-daily treatment with lotilaner ophthalmic solution 0.25% for 6 weeks generally was safe and well tolerated and met the primary end point and all secondary end points for the treatment of Demodex blepharitis compared with vehicle control. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

HSD39 Demodex Blepharitis Patient Journey: A Medical Chart Audit Study

Demodex blepharitis (Db) is an under-diagnosed disease caused by an overgrowth of Demodex mites. Db results in a chronic inflammation of the eyelid margin and has no FDA-approved treatments. This study aimed to understand how the disease is diagnosed and the patient journey in Db.

PCR92 Humanistic Burden of Illness in Demodex Blepharitis and Its Impact on Patients Lives Beyond the Presenting Symptoms

Demodex blepharitis (Db) is a chronic inflammation of the eyelid margin caused by an overgrowth of Demodex mites and has no FDA-approved treatments. This study assessed the humanistic burden of Db on patients’ daily lives.

Is Demodex Blepharitis Connected With Cataract Surgery?

To determine whether there is an increased incidence of Demodex of the eyelashes among patients after cataract extraction surgery. Prospective, noncomparative clinical study. A cohort of patients who underwent cataract extraction surgery had several eyelashes removed preoperatively that were examined independently by the hospital laboratory for the presence of the Demodex mite. This was repeated 3 weeks after surgery. During several postoperative weeks, patients received the standard treatment of steroid drops alone for a period as individually required. A total of 62 patients were included in the study (31 men and 31 women), with a mean age of 71.04 years (range, 47-87). In the group positive for Demodex, the male-to-female ratio was 2:3 (P=.2772). Demodex colonization was observed in 22.58% of samples before cataract surgery and in 32.26% after cataract surgery and topical postoperative steroid therapy (P=.0143). There is a statistically significant increase in Demodex colonization of eyelashes after cataract surgery and postoperative topical steroid treatment. Although Demodex colonization does not necessarily cause blepharitis, our findings of increased colonization should raise the possibility of Demodex blepharitis being considered by ophthalmologists in patients with chronic postoperative eye discomfort after cataract surgery. This study was carried out at the Emek Medical Center.

In Vivo View of a Reclining Demodex Mite in a Milia Cyst.

Demodex folliculorum and Demodex brevis are commonly present on facial skin and frequently noted via Reflectance Confocal Microscopy (RCM) examination. These mites inhabit follicles and are often seen in groups of two or more, although D. brevis is usually found as a solitary mite. When observed through RCM, they are typically present as refractile, round groupings seen on a transverse image plane inside the sebaceous opening, as they are vertically oriented, and their exoskeletons refract under near-infrared light. Inflammation may occur, leading to a variety of skin disorders; nonetheless, these mites are considered to be part of normal skin flora. a 59-year-old woman presented to our dermatology clinic for confocal imaging (Vivascope 3000, Caliber ID, Rochester, NY, USA) of a previously excised skin cancer for margin evaluation. She did not exhibit symptoms of rosacea or active inflammation of the skin. Incidentally, a solitary demodex mite was noted in a milia cyst nearby the scar. The mite appeared to be trapped in the keratin-filled cyst and was positioned horizontally to the image plane such that its entire body was captured in a coronal orientation as a stack. Demodex identification using RCM can provide clinical diagnostic value in the context of rosacea or inflammation; in our case, this solitary mite was thought to be part of the patient's normal skin flora. Demodex are practically ubiquitous on the facial skin of older patients and are frequently noted during RCM examination; however, the orientation of the mite referenced herein is uncommon, allowing for a unique view of its anatomy. The use of RCM to identify demodex may become more routine as access to technology grows.

Diagnosis and treatment of filamentary keratitis in a patient with Demodex infestation––an overlooked risk factor: a case report

BackgroundFilamentary keratitis is an ocular condition that is tricky to handle for the difficulty to find the underlying cause. Here we report a case of filamentary keratitis associated with Demodex infestation which highlights the importance of Demodex mites as an easily-overlooked risk factor.Case presentationA 63-year-old woman had recurrent symptoms of foreign body sensation and sometimes painful feelings in her left eye soon after her surgical correction of ptosis in this eye. She was then diagnosed as conjunctivitis and given antibiotic eye drops. After one week, the patient complained of aggravation of symptoms with small corneal filaments in the left eye under slit-lamp examination. Despite the removal of filaments and addition of topical corticosteroids and bandage contact lenses, the patient’s condition persisted with enlarged filaments and severe ocular discomfort. 3 days later, eyelashes with cylindrical dandruff were noticed and Demodex infestation was confirmed by microscopic examination of these eyelashes at our clinic this time. She was asked to use tea tree oil lid scrub twice daily. After 3 weeks, her filamentary keratitis was resolved with a dramatic improvement in symptoms and signs. And no recurrence of filamentary keratitis was noticed during the one-year follow-up.ConclusionsIn this case, filamentary keratitis was resolved only with treatment of Demodex infestation while conventional treatment failed. Considering the fact that Demodex infestation is a common but easily overlooked condition, it may be suggestive to take Demodex infestation into account as a risk factor of filamentary keratitis, especially in refractory cases.

Gene expression analysis of Canine Demodicosis; A milieu promoting immune tolerance

Canine demodicosis is a common skin disease seen in companion animal practice that results from an overpopulation of the commensal Demodex mite species. Common predisposing factors to the development of canine demodicosis include immunosuppressive diseases, such as neoplasia and hypothyroidism, and administration of immunosuppressive therapies, such as corticosteroids. Despite this, the pathogenesis of development of canine demodicosis remains unclear. Previous studies have implicated a role for increased expression of toll like receptor 2 (TLR2), increased production of interleukin (IL)-10) and T cell exhaustion. Here, we investigate gene expression of formalin fixed paraffin embedded skin samples from twelve cases of canine demodicosis in comparison to twelve healthy controls, using a 770 gene panel (NanoString Canine IO Panel). Results show an increase in the T cell population, specifically Th1 and Treg cells in dogs with demodicosis. In addition, while there is an upregulation of immunosuppressive cytokines such as IL-10 and IL-13, there is also an upregulation of immune check point molecules including PD-1/PD-L1 and CTLA-4. These findings suggest that Demodex spp. mites are modulating the host immune system to their advantage through upregulation of several immune tolerance promoting pathways.

Comparison of in vitro Killing Effect of Thai Herbal Essential Oils, Tea Tree Oil, and Metronidazole 0.75% versus Ivermectin 1% on Demodex folliculorum.

Abnormal proliferation of Demodex mites causes a skin disorder called demodicosis and has been linked to rosacea. The development of alternative therapy against Demodex mites is currently required. The ability to kill Demodex mites of Thai herbal essential oils has never been explored. This study aimed to study and compare the in vitro killing effect of Thai herbal essential oils, tea tree oil, and metronidazole 0.75% with ivermectin 1% on D. folliculorum. D. folliculorum mites were collected from the wastes of diagnostic standardized skin surface biopsy samples of demodicosis and rosacea patients for the trial. The microscopic evaluation started immediately after the mites were exposed to immersion oil (negative control), Thai herbal essential oils, tea tree oil, metronidazole 0.75%, and ivermectin 1% (positive control). The survival times of ten mites from each test agent were compared. The efficacy of Thai herbal essential oils and other test agents can be arranged in order as follows: lemongrass oil > sweet basil oil > clove oil > tea tree oil > lesser galangal oil > ginger oil, kaffir lime oil, peppermint oil > citronella oil > galangal oil > cajeput oil > ivermectin 1% > metronidazole 0.75%. This current study demonstrated the in vitro killing efficacy on D. folliculorum: Thai herbal essential oils, Tea tree oil > ivermectin 1% > metronidazole 0.75%. Thai herbal essential oils have the potential to be an adjuvant or alternative therapy against Demodex mites. Further in vivo studies are necessary to determine the treatment efficacy and side effects.

980 Demodex mites reveal an unanticipated expansion of innate lymphoid-like cells in immunodeficient mice

980 Demodex mites reveal an unanticipated expansion of innate lymphoid-like cells in immunodeficient mice

1576 Increased demodex mite population is involved with the cutaneous neurogenic inflammation in rosacea by upregulation of TRPV1 by NGF-TrkA activation

1576 Increased demodex mite population is involved with the cutaneous neurogenic inflammation in rosacea by upregulation of TRPV1 by NGF-TrkA activation

Demodex Blepharitis: A Survey-Based Approach to Investigate Knowledge, Attitudes, and Practices Among Optometrists in India.

To investigate the knowledge, attitudes, and practice towards Demodex blepharitis among optometrists in India. The study was conducted in the form of an online survey using Research Electronic Data Capture (REDCap). The survey link was distributed via direct e-mail and social media platforms, and it was comprised of 20 questions divided into two sections. The first section focused on the practitioners' demographics and their views on the general health of the eyelid. The second section of the survey was specific and aimed at obtaining information on identifying and treating Demodex blepharitis, and was only completed by those respondents who looked for Demodex mites. The survey was completed by 174 optometrists. The prevalence of blepharitis in the general population was judged by the respondents to be 40%, whereas the prevalence of Demodex mites was estimated to be 29%. Interestingly, the prevalence of Demodex mites in people with blepharitis was estimated to be 30%. This estimated prevalence was substantially lower than that reported in the literature on the subject. 66% of participants believed Demodex mites to be a significant cause of ocular discomfort, whereas only 30% of participants would intervene to diagnose and manage Demodex blepharitis in their patients. Optometrists differed in their preferred method of diagnosis and management of Demodex infestation in eyelids. The result of this survey suggests that Demodex blepharitis is a highly under-diagnosed condition in India, with nearly 30% of surveyed optometrists managing this condition. The study also observed a lack of awareness and consensus among surveyed optometrists with regards to diagnosis and appropriate treatment methods to control Demodex infestation in eyelids.

Demodicosis in Different Age Groups and Alternative Treatment Options—A Review

Infestation with Demodex mites is a common occurrence, especially in adults and the elderly. More recent attention has been paid to the presence of Demodex spp. mites in children, even ones without comorbidities. It causes both dermatological and ophthalmological problems. The presence of Demodex spp. is often asymptomatic, thus it is suggested to include parasitological investigation tests in dermatological diagnostics, in addition to bacteriological analysis. Literature reports show that Demodex spp. are related to the pathogenesis of numerous dermatoses, including rosacea or demodicosis gravis, and common eye pathologies reported by patients such as dry eye syndrome or ocular surface inflammatory conditions, such as blepharitis, chalazia, Meibomian gland dysfunction, and keratitis. Treatment of patients is a challenge and is usually prolonged, therefore it is important to carefully diagnose and properly select the therapy regimen for the treatment to be successful, and with minimal side effects, especially for young patients. Apart from the use of essential oils, research is ongoing for new alternative preparations active against Demodex sp. Our review was focused on the analysis of the current literature data on the available agents in the treatment of demodicosis in adults and children.