There is herein defined a phototherapy treatment device for use in therapeutic and/or cosmetic treatment of a variety of skin conditions such as acne and psoriasis. In particular, there is defined a self-adhesive ambulatory phototherapy treatment device for use in therapeutic and/or cosmetic treatment of a variety of skin conditions such as acne and psoriasis wherein there is an in-built light source (e.g. plurality of LED light sources, a single OLED sheet of light emitting material or a single high powered LED with a diffuser), a battery and control electronics.
