The topical treatment of psoriasis

Abstract

Topical treatments of psoriasis are a mainstay in its management. Topicals are particularly indicated in patients with mild disease, although those with more widespread psoriasis may benefit as well. An important limitation of topicals is low compliance. These issues will be discussed in the light of recent publications. In this review of recent literature, topical treatments will be categorized into (i) first‐generation (dithranol and coal tar); (ii) second‐generation (corticosteroids); (iii) third‐generation (vitamin D3, retinoids and calcineurin inhibitors); and (iv) fourth‐generation (innovations in vitamin D3 and retinoid signalling and small molecules targeted at epitopes identified by biologic treatments). In general, topical treatments are indicated for milder forms of psoriasis. However the definition of mild psoriasis as opposed to moderate and severe psoriasis is not at all clear. In general, objective dermatological assessments such as the Psoriasis Area and Severity Index (PASI), the body surface area involved, are used in most clinical trials. However, a patient may have very extensive psoriasis without substantial impairment of quality of life and with an excellent response to simple topical psoriasis. Does he still have severe psoriasis? On the other hand a patient with a few recalcitrant lesions may have a low PASI but severe impairment of quality of life and poor response even to major treatments. Does this patient still have mild psoriasis?