Emerging Sexually Transmitted Infections and Dermatologic Complications in Clinical Practice

Conclusions

• Long-acting injectable PrEP can cause injection-site reactions that are usually self-limited with cabotegravir but can persist for many months with lenacapavir, so early nodules are often expected and mainly require reassurance and follow-up.
• Vaccination does not rule out mpox, because post-vaccination mpox can present more subtly with fewer lesions, less mucosal involvement, and even painless genital ulcers, so clinicians should keep a low threshold to test.
• In 2026, mpox management is still largely supportive, with the biggest priorities being pain control, wound care, and immune optimization rather than relying on antiviral monotherapy.
• Tecovirimat monotherapy is not effective for most mpox cases, while severely immunocompromised patients with refractory disease may benefit from combination approaches or intralesional cidofovir in selected cases.
• Genital ulcers and other sexually associated dermatoses frequently overlap in appearance and context, so clinicians should test broadly for multiple STIs at the same visit rather than anchoring on a single diagnosis.
• Emerging sexually transmitted dermatophyte infections such as TMVII and T. indotineae are increasingly recognized, are often misdiagnosed, and can spread through sexual networks.
• For TMVII and related resistant dermatophytes, cultures should be obtained early and treatment usually needs to be prolonged, with better outcomes when therapy continues for 6 to 8 weeks or about 2 weeks beyond symptom resolution.
• Transmission counseling for sexually associated dermatophytes should emphasize avoidance of skin-to-skin contact and shared personal items, while also using nonjudgmental harm-reduction language to keep patients engaged in care.
• Doxy-PEP is generally effective at reducing chlamydia and syphilis, especially in men who have sex with men and transgender women, but its effect on gonorrhea is less reliable because of resistance.
• Doxy-PEP can produce dermatologic adverse effects such as rash, photosensitivity, and fixed drug eruptions, so new rashes in patients taking it should prompt a medication history.
• Doxy-PEP appears to increase tetracycline resistance in commensal bacteria and may shift skin flora, raising concern that tetracycline may become a poorer empiric choice for some skin and soft tissue infections.
• Gram-negative folliculitis and other altered-flora infections may emerge in the setting of antibiotic exposure, including doxy-PEP, so clinicians should consider unusual pathogens when beard or facial folliculitis is persistent or atypical.
• Taking a careful sexual history is essential in dermatology because it can reveal exposures that explain complex rashes, fungal infections, and folliculitis that would otherwise be misclassified.
• Overall, sexually transmitted and sexually associated skin conditions are increasingly overlapping with dermatology practice, making comprehensive testing, early culture, and interdisciplinary management more important than ever.