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.

Psoriasis is a chronic inflammatory skin disease that involves various systemic organs and tissues and is characterized by scaly erythematous skin. Among the different types of psoriasis, psoriatic arthritis (PsA) is frequently reported, and occasionally develops into severe arthritis leading to joint dysfunction. There are various tools, especially questionnaires, to identify the presence of PsA in European and American populations; however, little is known about the utility of these tools in the Asian population. In this study, we investigated the utility of a representative tool, the psoriasis epidemiology screening tool (PEST) questionnaire, to identify PsA among Japanese patients with psoriasis. A total of 143 patients with psoriasis were enrolled in this study. Among them, 29 patients were diagnosed with PsA. The frequency of PsA was significantly increased in patients with PEST scores > 3, with a sensitivity of 93.1% and a specificity of 78.9%. Among the questions in the PEST questionnaire, “Have you ever had a swollen joint?” showed the highest frequency to answer “Yes” among patients with PsA. Univariate and multivariate analyses revealed that high PEST scores (> 3) was an independent variable in PsA patients. Taken together, our study suggests that the PEST questionnaire is a useful tool to identify PsA among Japanese patients with psoriasis.