Trichophyton tonsurans-induced kerion celsi with decreased defensin expression and paradoxically increased interleukin-17A production

IL-17 in skin infections and homeostasis

Interleukin (IL) 17 is a proinflammatory cytokine belonging to a structurally related group of cytokines known as the IL-17 family. It has been profoundly studied for its contribution to the pathology of autoimmune diseases. However, it also plays an important role in homeostasis and the defense against extracellular bacteria and fungi. IL-17 is important for epithelial barriers, including the skin, where some of its cellular targets reside. Most of the research work on IL-17 has focused on its effects in the skin within the context of autoimmune diseases or sterile inflammation, despite also having impact on other skin conditions. In recent years, studies on the role of IL-17 in the defense against skin pathogens and in the maintenance of skin homeostasis mediated by the microbiota have grown in importance. Here we review and discuss the cumulative evidence regarding the main contribution of IL-17 in the maintenance of skin integrity as well as its protective or pathogenic effects during some skin infections.

Epidemiologic features and therapeutic strategies of kerion: A nationwide multicentre study

BACKGROUND

Kerion is a severe type of tinea capitis that is difficult to treat and remains a public health problem.

OBJECTIVES

To evaluate the epidemiologic features and efficacy of different treatment schemes from real-world experience.

METHODS

From 2019 to 2021, 316 patients diagnosed with kerion at 32 tertiary Chinese hospitals were enrolled. We analysed the data of each patient, including clinical characteristics, causative pathogens, treatments and outcomes.

RESULTS

Preschool children were predominantly affected and were more likely to have zoophilic infection. The most common pathogen in China was Microsporum canis. Atopic dermatitis (AD), animal contact, endothrix infection and geophilic pathogens were linked with kerion occurrence. In terms of treatment, itraconazole was the most applied antifungal agent and reduced the time to mycological cure. A total of 22.5% of patients received systemic glucocorticoids simultaneously, which reduced the time to complete symptom relief. Furthermore, glucocorticoids combined with itraconazole had better treatment efficacy, with a higher rate and shorter time to achieving mycological cure.

CONCLUSIONS

Kerion often affects preschoolers and leads to serious sequelae, with AD, animal contact, and endothrix infection as potential risk factors. Glucocorticoids, especially those combined with itraconazole, had better treatment efficacy.

Tinea capitis caused by Trichophyton violaceum in an immunocompetent elderly patient: A case report and review of literature

Tinea capitis is a common dermatophyte infection of the scalp in children. It is an uncommon infection in adults and usually affects postmenopausal women and immunocompromised patients. We report an immunocompetent elderly female with inflammatory tinea capitis caused by Trichophyton violaceum and review the literature for the past 5 years to describe the disease, its epidemiologic characteristics, dermatophyte species involved and treatment options used. The total number of cases was 11, including 8 women and 3 men, with an average age of 48.36. The most commonly isolated dermatophyte was Trichophyton tonsurans, and most cases were treated successfully with oral terbinafine with no side effects. In our case, the diagnosis was established by direct examination, culture and histological examination. Remedy with itraconazole and prednisolone was very successful. Early diagnosis of tinea capitis in adults is necessary to provide early treatment and minimize sequelae of the disease.

Revisiting the pathogenesis of dermatophytosis: A cross-sectional analytic study of serum levels of interleukins-2, 8, 10 and 17

BACKGROUND

Given the current epidemic-like scenario of dermatophyte infections, it is prudent to revisit the immunopathogenesis of dermatophytosis. Comprehending the intricate interactions among interleukins can aid in understanding the recent trends in infection. There is a paucity of literature on the various cytokine levels observed in the serum of patients suffering from various dermatophytoses.

AIM

To study serum cytokine levels of interleukins 2, 8, 10 and 17 in patients with dermatophytosis.

METHODS

A cross-sectional analytic study was conducted on 64 cases of clinical dermatophyte infections (KOH confirmed) and 64 controls. The clinico-epidemiological profile of the cases was studied. By using a solid phase sandwich ELISA (enzyme-linked immunosorbent assay), the serum levels of interleukins 2, 8, 10 and 17 were measured and compared between cases and controls. Serum interleukin-2, 8, 10 and 17 levels were studied among cases based on mode of onset, duration of illness, treatment history, site of infection and multiple other morphological characteristics of the infection.

RESULTS

The cases had statistically higher levels of interleukins-8, 10 and 17 in comparison with controls. The levels of interleukin-8 were significantly lower (p < .05) among those who had received oral antifungals. In cases where the lesion had scaling, the serum levels of interleukin-10 were significantly higher (p < .05). The lesional hyperpigmentation was significantly (p < .05) associated with low levels of interleukin-17. Also, interleukin-17 was significantly (p < .05) elevated in patients with lesions in the abdomen.

CONCLUSION

It is the first time that serum interleukin levels are studied in dermatophytosis. There is an immunological dysfunction specific to dermatophytoses initiated by their infection. Key factor in this dysfunction is the elevation of IL-10, contributing to persistent infection. In turn, causing an increase in IL-17, promoting inflammation and tissue damage. This cycle of elevated IL-10 and IL-17 can further exacerbate the infection and lead to chronicity. The activity of IL-2 and the Th1 immune pathway is reduced by two opposing immune pathways: the Th17 and Th2 axes.

The Role of IL-17-Producing Cells in Cutaneous Fungal Infections

The skin is the outermost layer of the body and is exposed to many environmental stimuli, which cause various inflammatory immune responses in the skin. Among them, fungi are common microorganisms that colonize the skin and cause cutaneous fungal diseases such as candidiasis and dermatophytosis. The skin exerts inflammatory responses to eliminate these fungi through the cooperation of skin-component immune cells. IL-17 producing cells are representative immune cells that play a vital role in anti-fungal action in the skin by producing antimicrobial peptides and facilitating neutrophil infiltration. However, the actual impact of IL-17-producing cells in cutaneous fungal infections remains unclear. In this review, we focused on the role of IL-17-producing cells in a series of cutaneous fungal infections, the characteristics of skin infectious fungi, and the recognition of cell components that drive cutaneous immune cells.