Retinoids

This is the generic name given to a range of medications all related to vitamin A. For psoriasis treatment the specific retinoid which is used is known as acitretin. It works by altering keratinisation and epidermal differentiation having anti-proliferative, anti-inflammatory and anti-keratinising effects on the skin (Naldi and Griffiths, 2005). Retinoids are complex drugs with many possible side effects; however, they are effective at treating psoriasis (Griffiths et al., 2000), and as mentioned previously used in conjunction with PUVA their effect may be enhanced thus allowing for a reduced exposure to UV radiation.

Retinoids can affect hepatic function and lead to hyperlipidaemia. It is also highly teratogenic and therefore not suitable for pregnant women or women who are considering becoming pregnant. Women should take contraceptive precautions for 2 years after discontinuing retinoid therapy (Griffiths et al., 2000). Common less severe side effects include dry mucous membranes including eyes, lips and throat (if a patient’s lips do not become dry it is reasonable to assume they are not complying with treatment or the dosage is sub-therapeutic) (see Box 8.5 for further common skin related side effects).

Box 8.5 Common skin and mucous membrane changes seen with use of acitretin Dry mucous membranes including dry lips (cheilitis), dry mouth, dry eyes and dry nasal mucosa Altered skin sensation–skin feels sticky Dry skin Dermatitis Flare of psoriasis Peeling of finger-tips, palms or soles Skin fragility Itch Hair loss Hair texture change Nail changes including paronychia