Demodex spp. as a possible aetiopathogenic factor of acne and relation with acne severity and type

Microbiome: Role in Inflammatory Skin Diseases

As the body's largest organ, the skin harbors a highly diverse microbiota, playing a crucial role in resisting foreign pathogens, nurturing the immune system, and metabolizing natural products. The dysregulation of human skin microbiota is implicated in immune dysregulation and inflammatory responses. This review delineates the microbial alterations and immune dysregulation features in common Inflammatory Skin Diseases (ISDs) such as psoriasis, rosacea, atopic dermatitis(AD), seborrheic dermatitis(SD), diaper dermatitis(DD), and Malassezia folliculitis(MF).The skin microbiota, a complex and evolving community, undergoes changes in composition and function that can compromise the skin microbial barrier. These alterations induce water loss and abnormal lipid metabolism, contributing to the onset of ISDs. Additionally, microorganisms release toxins, like Staphylococcus aureus secreted α toxins and proteases, which may dissolve the stratum corneum, impairing skin barrier function and allowing entry into the bloodstream. Microbes entering the bloodstream activate molecular signals, leading to immune disorders and subsequent skin inflammatory responses. For instance, Malassezia stimulates dendritic cells(DCs) to release IL-12 and IL-23, differentiating into a Th17 cell population and producing proinflammatory mediators such as IL-17, IL-22, TNF-α, and IFN-α.This review offers new insights into the role of the human skin microbiota in ISDs, paving the way for future skin microbiome-specific targeted therapies.

The Association Between Acne Vulgaris, Acne Vulgaris with Nonspecific Facial Dermatitis, and Demodex Mite Presence

Background

Demodex mites can lead to various skin disorders, from non-specific dermatitis to conditions that mimic other diseases, making it challenging to diagnose accurately. Additionally, it has been reported that Demodex mites can cause skin conditions such as perioral dermatitis, pustular folliculitis, pityriasis folliculorum, blepharitis, and rosacea. Due to conflicting studies, there is a debate regarding the link between Demodex mites and acne vulgaris. This study aims to determine the prevalence of Demodex mites on the faces of individuals with acne vulgaris, acne with nonspecific facial dermatitis, and healthy facial skin to clarify the association.

Materials and Methods

This observational case-control study involved 120 participants aged 18-37: 40 individuals with acne vulgaris only, 40 with acne and nonspecific facial dermatitis, and 40 healthy controls. The same dermatologist examined and diagnosed all participants to ensure accuracy before being grouped. The Standardized Skin Surface Biopsy (SSSB) method was used to detect Demodex mites in all three study groups. Furthermore, additional samples were collected randomly from acne lesions using the Superficial Needle Scraping (SNS) method in the two acne groups.

Results

The study found no significant difference in Demodex prevalence and high Demodex density rate between patients with only acne vulgaris and the control group (p>0.05). However, acne patients with nonspecific facial dermatitis had a higher rate of Demodex prevalence and high Demodex density rate than the only acne vulgaris and control group (p<0.05). The clinical symptoms of nonspecific facial dermatitis in acne patients strongly associated with Demodex mites are patchy red, dry, scaly skin, roughness, insect bite-like papules, and flushing.

Conclusion

Demodex prevalence and high Demodex density rate are not associated with acne vulgaris. Still, it is associated with acne and nonspecific facial dermatitis, particularly in patients with patchy redness, dry, scaly skin, roughness, insect bite-like papules, and flushing.

Advances in Relationship Between Alcohol Consumption and Skin Diseases

Throughout history, alcohol consumption has been an integral part of human culture. Alcohol consumption, alcoholism in particular, influences the onset and progression of liver diseases, neurological disorders, and multiple types of cancer. However, the role of alcohol consumption in influencing skin diseases has often been overlooked. In this review, we present the progress of research investigating the effects and potential mechanisms of action of alcohol consumption on acne, rosacea, psoriasis, atopic dermatitis, melanoma, and non-melanoma skin cancer.

Targeting Inflammation in Acne: Current Treatments and Future Prospects

Acne is a common, chronic inflammatory condition affecting millions of people worldwide, with significant negative impact on quality of life and mental health. Acne is characterized by comedones, inflammatory papules, pustules, and nodulocystic lesions, with long-lasting sequelae including scarring and dyspigmentation, the latter of which is more common in skin of color. The four main pillars of acne pathophysiology include alteration of sebum production and concentration, hyperkeratinization of the follicular unit, Cutibacterium acnes strains, and an inflammatory immune response. Newer research has provided greater insight into these pathophysiologic categories. This greater understanding of acne pathogenesis has led to numerous new and emerging treatment modalities. These modalities include combinations of existing treatments, repurposing of existing agents historically used for other conditions, new topical treatments, novel antibiotics, topical and oral probiotics, and various procedural devices. This article will provide an overview of emerging treatments of acne and their link to our current and improved understanding of acne pathogenesis.

Photodynamic therapy treats acne by altering the composition of the skin microbiota

BACKGROUND

Acne is the eighth-most prevalent inflammatory skin disease with no optimal treatment. Photodynamic therapy (PDT) is an effective treatment for severe acne.

AIMS

The effect of PDT on the composition and diversity of skin microflora in severe acne patients was studied.

MATERIALS AND METHODS

A total of 18 patients with severe acne and 8 healthy individuals were selected for this study. Patients were treated with 5-aminolevulinic acid-mediated PDT once a week three times in total; the skin microbiome was measured by 16S ribosomal RNA gene sequencing before and after treatment (1 week after each PDT).

RESULTS

The microflora composition was different between healthy controls and patients, and between patients before and after treatment. Alpha diversity indices were lower in patients than those in control. There were 15 bacterial genera with high relative abundance that had noticeable changes during treatment. At the genus level,particularly Cutibacterium acnes (C. acnes formerly Propionibacterium acnes), there was no statistically significant difference among different group. The abundances of Staphylococcus epidermidis and Staphylococcus aureus were low.

DISCUSSION

The microbial composition is different between severe acne patients acne patients and healthy individuals. The therapeutic efficacy of severe acne treated with PDT is associated with the composition and diversity of skin microbiota.

CONCLUSION

The skin microbial composition changes after PDT treatment. PDT is an effective method for the treatment of severe acne.

Demodicosis Imitating Acne Vulgaris: A Case Report

Demodicosis is caused by Demodex mite infestation and can present with a variety of clinical manifestations, including pityriasis folliculorum type, rosacea-like type, folliculitis-like type and perioral dermatitis-like type. Therefore, this skin condition is often misdiagnosed or underdiagnosed. This report presents a 19-year-old woman with a history of pityriasis folliculorum type demodicosis and successful treatment with oral ivermectin. After one year of remission, the patient began to develop a dry, itchy rash on her face for one month before multiple small edematous papules and pustules gradually appeared on both cheeks. The patient was first diagnosed as acne vulgaris and treated with doxycycline for 2 weeks, but the clinical symptoms did not show any signs of improvement. After reassessment based on clinical presentation and laboratory examination that found multiple Demodex mites from pustules and rash on both cheeks, the patient was diagnosed with folliculitis-like type demodicosis. However, this patient still had a very good response to oral ivermectin and metronidazole gel, and all clinical symptoms disappeared within 4 weeks after treatment. This is a case report of demodicosis imitating acne vulgaris and the first report demonstrating a change in clinical manifestations of demodicosis from pityriasis folliculorum type to folliculitis-like type.

Demodex: the worst enemies are the ones that used to be friends

Demodex mites are common ectoparasites of the human pilosebaceous units. Most adults are infested with Demodex mites without clinical symptoms. Demodex mite will only become a pathogenic organism when there is an abnormal increase in the number of Demodex mite density. This situation happens when the equilibrium between Demodex mites, skin microenvironment and human immunity system changes. Demodex infestation can cause multiple skin disorders, which are grouped under the term demodicosis or demodicidosis. Clinical manifestations of demodicosis can mimic other known skin diseases such as folliculitis, rosacea, perioral dermatitis, which is why it is often misdiagnosed. Diagnosis criteria consists of relevant correlation of suspected clinical skin lesions, confirmed by the presence of abnormal proliferation of Demodex mites and by clinical cure after acaricidal treatment together with normalization of Demodex mite density. Dermatologists should be aware that demodicosis is not an uncommon skin disease, and there are still many unknowns about it that should be researched further.

Investigation of the Prevalence of Demodex spp. in Dermatological Diseases

OBJECTIVE

An increase in the counts of the Demodex mites that exist in the microbiota of healthy individuals may lead to some dermatological diseases. This study aimed to investigate the prevalence of Demodex spp. among patients diagnosed with acne vulgaris, rosacea, perioral dermatitis, seborrheic dermatitis, eczema, and pityriasis folliculorum and the relationship between the demographic and clinical data of such patients and Demodex.

METHODS

This study included 144 patients (70 with acne vulgaris, 6 with pityriasis folliculorum, 15 with seborrheic dermatitis, 39 with rosacea, 8 with eczema, and 6 with perioral dermatitis) and 73 healthy subjects. We evaluated Demodex positivity using the standard superficial skin biopsy method in all groups. The presence of more than five Demodex mites per square centimeter was considered positive at the diagnosis.

RESULTS

Of the 144 patients included in the study, 107 (74.3%) were female, and 37 (25.7%) were male, while 40 (54.8%) of the 73 healthy subjects were female, and 33 (45.2%) were male. Twenty-one patients (14.5%) and five of the healthy subjects (6.8%) tested positive for Demodex. We found that Demodex positivity rates in the rosacea and acne vulgaris groups were higher than in the control group. However, this level was not statistically significant (p>0.05). We found the highest positivity rate among the patient groups in the pityriasis folliculorum (4/6, 66.7%), rosacea (8/39, 20.5%), and perioral dermatitis (1/6, 16.7%) groups. Lastly, we found no statistically significant relationship between the demographic and clinical characteristics of the groups and Demodex positivity (p>0.05).

CONCLUSION

The present study is the only study that investigated Demodex positivity in six different dermatological diseases. Based on the results, we believe that investigating Demodex spp. positivity in dermatological diseases such as acne vulgaris, rosacea, and pityriasis folliculorum would be beneficial for early diagnosis and treatment.

Demodex Mites in Relation to the Degree of Acne Vulgaris among Egyptian Patients

&lt;b&gt;Background and Objective:&lt;/b&gt; &lt;i&gt;Demodex&lt;/i&gt; mites are considered to play a pathogenic role in facial dermatoses as &lt;i&gt;Acne vulgaris&lt;/i&gt;. In this study the association between &lt;i&gt;Acne vulgaris&lt;/i&gt; and &lt;i&gt;Demodex&lt;/i&gt; spp. intensity, kind and activity were investigated. &lt;b&gt;Materials and Methods:&lt;/b&gt; Two degrees of acne was included, mild acne (30 cases) and moderate to severe acne (30 cases), besides 30 healthy subjects as a control. Deep skin scraping followed by direct microscopic detection was applied to diagnose demodicosis. &lt;b&gt;Results:&lt;/b&gt; All the detected mites in moderate to severe acne were &lt;i&gt;D. folliculorum&lt;/i&gt; which was observed in a highly dynamic status with their entire life cycle stages with intensity >5 mites per cm&lt;sup&gt;&lt;a href="2246157_ja"&gt;2&lt;/a&gt;&lt;/sup&gt;. While very few inactive &lt;i&gt;D. brevis&lt;/i&gt; mites were detected in the 2 subjects related to the control group&lt;i&gt;. &lt;/i&gt;Despite that females comprised the majority of acne cases, males encompassed a statistically higher number than females among positive demodicosis cases. Itching and hair loss were the significant clinical signs within positive cases. Regarding risk factors, oily skins, repeated exposure to the sun, stressful lifestyle plus defective use of facial cleansers were found to be statistically significant. &lt;b&gt;Conclusion:&lt;/b&gt; These results attained an association between moderate to severe acne and energetic &lt;i&gt;D. folliculorum&lt;/i&gt; entire population. Thus, this study recommended lifestyle's modification for those cases suffering from &lt;i&gt;Acne vulgaris&lt;/i&gt; with deep facial cleaning to avoid such infestation that worsens acne condition. Accordingly, once acne treatments are ineffective, consideration of &lt;i&gt;Demodex&lt;/i&gt; mites with the needed acaricidal therapy is necessary.

Comparison of the efficacy of tea tree (Melaleuca alternifolia) oil with other current pharmacological management in human demodicosis: A Systematic Review

Various treatments are found to be moderately effective in managing Demodex-related diseases except tea tree oil (TTO) and terpinen-4-ol (T4O), which showed superior miticidal and anti-inflammatory effects in numerous clinical studies. Their possible effects include lowering mite counts, relieving Demodex-related symptoms, and modulating the immune system. This review summarizes the current clinical topical and oral treatments in human demodicosis, their possible mechanisms of action, side-effects and resistance in treating this condition. TTO (especially T4O) is found to be the most effective followed by metronidazole, ivermectin and permethrin in managing the disease. This is because TTO has anti-parasitic, anti-bacterial, anti-fungal, anti-inflammatory and wound-healing effects. Furthermore, nanoTTO can even release its contents into fungus and Pseudomonas biofilms. Combinations of different treatments are occasionally needed for refractory cases, especially for individuals with underlying genetic predisposal or are immuno-compromised. Although the current treatments show efficacy in controlling the Demodex mite population and the related symptoms, further research needs to be focused on the efficacy and drug delivery technology in order to develop alternative treatments with better side-effects profiles, less toxicity, lower risk of resistance and are more cost-effective.

Characterization and Analysis of the Skin Microbiota in Acne: Impact of Systemic Antibiotics

Systemic antibiotics are extensively used to control moderate to severe acne. Hence, it is crucial to understand their impact on the skin microbiota, which is supposedly perturbed. The purpose of this study was to compare the makeup and diversity of the skin microbiota in acne patients before and after taking oral antibiotics. A longitudinal cohort study was performed on 20 participants with moderate to severe facial acne with no recent use of oral and topical antibiotics/retinoids. Patients were prescribed oral doxycycline, 100 mg, twice daily for six weeks. Skin areas on the cheek were sampled for 16S ribosomal RNA gene sequencing at baseline, and after six weeks of doxycycline treatment. Ten males and 10 females aged 11 to 44 years with a median Investigator’s Global Assessment score of 3 (moderate) were enrolled. At baseline, Cutibacterium acnes (formerly Propionibacterium acnes) was the most dominant species followed by Staphylococcus epidermidis. Acne severity showed a positive correlation with the abundance of Cutibacterium acnes. Across all subjects, antibiotic treatment reduced clinical acne grades and was associated with a 1.96-fold reduction in the relative abundance of Cutibacterium acnes (p = 0.01, 95% CI −22% to −3%). Marked changes were also identified in other bacterial species, such as Cutibacterium granulosum (formerly Propionibacterium granulosum), which increased by 4.46-fold (p = 0.02, 95% CI 0.004% to 0.9%) in the treated samples. In general, antibiotics administration was associated with an increase in bacterial diversity (alpha diversity). Principal coordinates analysis showed mild clustering of samples by patient (analysis of similarity, R = 0.135, p = 0.04) whereas there was scant clustering with treatment (ANOSIM, R = 0.005; p = 0.29). In conclusion, we found individuals with acne to have a unique microbial signature. Acne treatment with systemic antibiotics was associated with changes in the composition and diversity of skin microbiota, especially Cutibacterium acnes, which correlates with acne severity. Our study provides insight into the skin microbiota in acne and how it is modulated by systemic antibiotics.

Ocular demodicosis: A review

Demodex folliculorum and Demodex brevis are ectoparasites that inhabit the skin of humans. They have been related to alterations in the ocular surface, such as, dysfunction of Meibomian glands, blepharitis, chalazion, etc. Ocular demodicosis is characterised by the pathognomonic presence of cylindrical dandruff at the base of the eyelashes, and various symptoms including, among others, itching, lacrimation, and hyperaemia. A bibliographic review was carried out on the role of Demodex spp. in ocular disease, including publications made by the scientific society between 2005 and 2018. A significant relationship was found between prevalence and incidence of Demodex spp. in eye diseases. D. folliculorum is usually found more frequently than D. brevis in ocular infestation, with the prevalence or incidence of infestation by both species increasing with the age of the patient. In patients with blepharitis or other infectious diseases of the ocular surface, unresolved with antibacterial treatment, the search for Demodex spp. should be considered.