The photodermatoses are a diverse group of conditions in which abnormal responses to light exposure are the hallmark. Photodiagnostic investigations through a specialist unit may be essential to ensure accurate diagnosis and management, and this chapter explores the nature of the photodermatoses and the photodiagnostic techniques that can be applied. Management approaches include early diagnosis, prevention and disease suppression, and awareness of the significant adverse impact on well‐being and psychological health that can occur with photosensitivity. Photoprotection is a mainstay approach for the photodermatoses but is often not sufficient alone for disease control. Desensitisation through natural hardening or light‐based therapies may be feasible, although systemic immunosuppressants and immunomodulators may be required. Awareness of the possibility of vitamin D deficiency is also necessary. This chapter will cover these approaches in detail.