Psoriasis: Topical treatment

K Pavithran

 Department of Dermato-Venereology, Medical College Hospital, Calicut-673008, India

Correspondence Address:
K Pavithran
Department of Dermato-Venereology, Medical College Hospital, Calicut-673008
India

In the management of psoriasis I always keep in mind the fundamental principle of dermatotherapy i.e ′soothen the acute and wipe out the chronic′. When a patient has exfoliative, guttate or unstable form of psoriasis, only soothing oils such as liquid paraffin, or vaseline are applied that too after proper hydration of skin. Even if patient doesn′t take bath, he can wet the skin with moist bath towel before applying the oil. If exfoliative psoriasis is associated with itching, soothing bath with starch (1/2, to 1 pound dissolve in cold water and then add boiling water) or potassium permanganate 5-15g in one bath tub water (150-250 litres) will be beneficial.

Scalp psoriasis: If scaling is mild, a simple non irritating shampoo bath is enough. When the scales are exuberant and firmly adherent to the skin and hairs (tinea amiantacea) coal tar and salicylic acid in coconut oil (acid salicylic 3, liquor picis carbonis 6, coconut oil 100) is applied for 2 hours and warm oil is then applied 20 minutes before bath. This will loosen the adherent scales. During bath, a soap substitute such as copra cake or green gram powder is used to remove the loosened scales. After bath and drying the hairs, he can apply 10-12 drops of betamethasone scalp lotion.

Palmo-plantar psoriasis : Psoriatic plaques of palms and soles are resistant to usual lines of treat-ment. They should be advised to avoid contact with soap and detergents. I instruct them to apply dithranol 1% ointment for 2 hours over the plaques and then remove the medicine by wiping with a cloth dipped in warm mineral oil (liquid paraffin). At night they are advised to immerse the hands and feet in water for 30 minutes and then apply the following ointment before occlusive dressing.

Acid salicylic g3, clobetasole propionate 0.5% ointment g 30, vaseline g 30.

Psoriatic lesions on the face, body flexures and glans penis are treated with twice daily application of IFTU of mild steroids (clobetasone/ fluticasone/mometasone furoate).

For generalised or localised pustular psoriasis potassium permanganate bath (15g/bath tub water) or compresses (one or two specks of crystal in 2 litres water just to cause a light pink colour) is recommended.

For nail psoriasis I prescribe potent corticoids such as clobetasole or beclomethasone dipropionate to be applied on the skin of posterior nail fold and adjascent skin so that the drug will be absorbed through skin and act directly on nail matrix cells thereby normalising the keratinization process there.

For stable psoriatic plaques (no increase in size or erythema, no new lesions) I prescribe topical dithranol (1%) ointment for application on the plaques for 2 hours and then wipe it with a cloth dipped in warm liquid paraffin. The skin around the plaques should be smeared with vaseline to prevent irritant dermatitis. At night patient can apply the following ointment.

Acid salicylic 3, liquor picis carbonis 6, Vaseline 100.

Depending on the response to treatment (increase or decrease in thickness) the concentration of tar and salicylic acid can be increased or decreased (tailor made prescription).