Presentations

A wide range of proprietary moisturising and emollient products is available in a variety of presentations, including creams, ointments, gels, lotions, bath and shower oils, water-dispersible bath additives, an aerosol spray and a shower gel. There are also some inexpensive formulary preparations, including emulsifying ointment BP and aqueous cream BP, the latter consisting of 30 per cent emulsifying ointment with water. These may be as effective as more expensive products, although less cosmetically elegant.

Active constituents

DITHRANOL In a cream presentation, dithranol is indicated for the topical treatment of subacute and chronic psoriasis, including psoriasis of the scalp. Its mode of action has not been established, but it has been shown to inhibit DNA replication, cellular respiration and key cellular enzymes such as glucose-6-phosphate dehydrogenase.

It can cause skin irritation and staining of fabrics. The cream is available in five strengths, from 0.1 to 2.0 per cent, and all are licensed as P medicines. Dithranol should, however, only be used under medical supervision.

COAL TAR Available as a cream, a bath additive and a shampoo, coal tar is used for the treatment of sub-acute and chronic psoriasis, including of the scalp. Its precise mechanism of action is not understood, but there is evidence that topical application improves psoriasis by reducing the excessive rate of mitotic epidermal cell division. The cream and shampoo also contain lecithin, a phospholipid which softens psoriasis scales and enhances the absorption of the coal tar. 

CLOBETASONE AND HYDROCORTISONE Creams containing these steroidal anti-inflammatories are licensed for the short-term treatment and control (up to one week) of patches of eczema and dermatitis, including atopic eczema and primary irritant and allergic dermatitis, in adults and children over 12 years for clobetasone and over 10 years for hydrocortisone.

They reduce inflammation by stabilising cell membranes, which prevents release of destructive enzymes, antagonises histamine and the release of kinins, inhibits accumulation of macrophages, and reduces capillary wall permeability and oedema formation.