Unveiling the Role of Endoplasmic Reticulum Stress Pathways in Canine Demodicosis

Canine demodicosis is a prevalent skin disease caused by overpopulation of a commensal species of Demodex mite, yet its precise cause remains unknown. Research suggests that T-cell exhaustion, increased immunosuppressive cytokines, induction of regulatory T cells and increased expression of immune checkpoint inhibitors may contribute to its pathogenesis. This study aimed to gain a deeper understanding of the molecular changes occurring in canine demodicosis using mass spectrometry and pathway enrichment analysis. The results indicate that endoplasmic reticulum stress promotes canine demodicosis through regulation of three linked signalling pathways: eIF2, mTOR, and eIF4 and p70S6K. These pathways are involved in the modulation of Toll-like receptors, most notably TLR2, and have been shown to play a role in the pathogenesis of skin diseases in both dogs and humans. Moreover, these pathways are also implicated in the promotion of immunosuppressive M2 phenotype macrophages. Immunohistochemical analysis, utilising common markers of dendritic cells and macrophages, verified the presence of M2 macrophages in canine demodicosis. The proteomic analysis also identified immunological disease, organismal injury and abnormalities and inflammatory response as the most significant underlying diseases and disorders associated with canine demodicosis. This study demonstrates that Demodex mites, through ER stress, unfolded protein response and M2 macrophages contribute to an immunosuppressive microenvironment, thereby assisting in their proliferation.

Iatrogenic Demodex folliculitis: A case report

Demodex folliculorum is a commensal mite that inhabits the orifices of cutaneous pilosebaceous follicles. Overgrowth of these organisms can lead to Demodex folliculitis, which typically presents as papules and pustules predominantly involving the temples, cheeks, and occasionally the chest. We present a 51-year-old woman with iatrogenic Demodex folliculitis secondary to immunosuppressive treatment for an autoimmune connective tissue disease. Histopathological exam of a skin biopsy, which revealed follicular Demodex mites, confirmed the diagnosis. The eruption was treated with oral ivermectin and topical metronidazole gel, and the patient's immunosuppressive regimen was decreased, resulting in marked improvement in the eruption within 6 weeks and no worsening of her underlying autoimmune disorder. This case emphasizes the importance of considering Demodex folliculitis in the differential diagnosis of a new onset rash in the context of immunosuppressive treatment.

The comparative in vitro killing activity of tea tree oil versus permethrin on Demodex folliculorum of rosacea patients

BACKGROUND

Demodex mites have been implicated in several cutaneous disorders compelling the research efforts for effective anti-Demodex therapy.

OBJECTIVE

Compare the survival time (ST) of Demodex folliculorum exposed to six different concentrations of tea tree oil (TTO) versus a positive control (permethrin 5%) and a negative control (immersion oil) group.

MATERIALS AND METHODS

The wastes of rosacea patients' standardized superficial skin biopsy samples were recruited for the trial. The primary outcome measure of this study was the survival time, defined as the period between the exposure of study agents to the complete cessation of Demodex movements.

RESULTS

All differences between the mean survival times of 2.5% (54.0 ± 6.1), 5% (39.0 ± 3.9), 10% (22.0 ± 2.5), 25% (13.0 ± 2.5), 50% (7.8 ± 0.6), and 100% TTO (3.3 ± 1.3) were significant (p < 0.05). The ST of the negative control group was 196.0 ± 23.6 min. The ST of permethrin 5% was 12.5 ± 1.9 that did not show a statistically significant difference from the ST of TTO 25% (p = 0.628).

CONCLUSION

The survival times of the six different TTO groups confirmed a dose-related pattern, all of which had survival times shorter than the negative control (immersion oil). TTO 25% had comparable efficacy to the positive control agent (permethrin 5%).

A case series of demodicosis in children

Demodex mites are commensal inhabitants of the pilosebaceous unit that are typically absent or at low numbers in childhood. When they are present, they can cause a primary eruption or exacerbate an underlying facial dermatosis. Here we report five cases of demodicosis occurring in childhood, the clinical presentations, and responses to treatment. Papulopustular lesions predominate, prompting the advice "pustules on noses, think demodicosis!"