New Perspectives on Cutaneous and Sexually Transmitted Infections: Clinical, Epidemiological, and Therapeutic Updates

Sexually transmitted infections (STIs) remain a global health burden. Beyond classical pathogens, dermatophytes are increasingly identified within sexually linked transmission networks. Genital dermatophytosis is a superficial fungal infection of the genital area, primarily caused by anthropophilic and zoophilic dermatophytes. Recently, Trichophyton mentagrophytes genotype VII and Trichophyton indotineae have emerged as clinically significant dermatophytes, increasingly linked to human-to-human and sexually associated transmission within highly interconnected sexual networks. These infections are often marked by inflammatory, persistent, and treatment-refractory presentations, with prominent genital involvement and rising antifungal resistance—particularly to terbinafine—posing growing diagnostic and therapeutic challenges. Doxycycline post-exposure prophylaxis (Doxy-PEP) has recently emerged as a novel preventive strategy for bacterial STIs, involving the administration of 200 mg doxycycline within 24–72 h after activities associated with increased infection exposure, particularly among men who have sex with men (MSM) and transgender women. While effective in reducing infections such as syphilis and chlamydia, its broader implementation raises concerns regarding antimicrobial resistance. Chemsex is an increasingly prevalent behavioural phenomenon, defined as the intentional use of psychoactive substances during sexual activity to enhance or prolong the experience, particularly among MSM. It is associated with multiple adverse effects, including increased STI transmission, substance dependence, drug toxicity, psychological disturbances, and significant challenges in treatment adherence and healthcare engagement. This review aims to provide a comprehensive and clinically oriented overview of emerging trends in STIs, with a particular focus on dermatophyte infections as pathogens with potential sexually associated transmission, alongside evolving prevention strategies and behavioral factors influencing transmission.