Safe and effective use of phototherapy and photochemotherapy in the treatment of psoriasis

Heliotherapy, the therapeutic use of sunlight, has been used for centuries in the treatment of skin disease (Hönigsmann, 2013). Phototherapy with artificial sources of ultraviolet (UV) radiation is more effective than sunlight, because reducing exposure to harmful and less beneficial rays allows a higher dose of effective UV to be given. The phototherapies remain a treatment option for skin conditions such as atopic eczema, urticaria and vitiligo.

Psoriasis is the main indication, accounting for more than 50% of treatment courses (Ibbotson, 2018). First-line therapies for psoriasis include topical corticosteroids, vitamin D analogues, tar and dithranol. As a second-line therapy, UV treatment is considered appropriate when topical therapies are not controlling the patient's psoriasis adequately or when psoriasis is so widespread that topical application is not practicable. These treatments should be considered before the use of third-line systemic treatments, such as methotrexate or biological interventions (Ling et al, 2016), although individual patient circumstances need to be taken into account.