These are the major conventional treatments, and their possible side effects. None claims a cure, although some claim a measure of success in suppressing symptoms. Be warned, though some side effects are worse than the condition being treated.
Calcipotriol (Dovonex). Early studies indicate that it is at least as effective as the steroid betamethasone, if not more so, for plaque psoriasis (K Kragballe et al, The Lancet, 26 January 1991), and is superior to short term dithranol. It should never be used for the face as it produces soreness. Calcipotriol should never be used by fair skinned people who burn easily in the sun; patients who have recently had courses of etretinate, which increases skin sensitivity; and patients who have been treated with strong corticosteroids long term. It should be used only six weeks at a time. Patients need to be careful about exposure to the sun with it. Maximum recommended amount is 100g a week.
Cyclosporin. This is increasingly used for refractory psoriasis. It is a powerful immunosuppressant, extensively used in organ transplants. A US study (Charles Ellis et al, University of Michigan Medical Centre, NEJM, 31 January 1991) of 85 plague psoriasis sufferers found that with a dosage of 5 mg per day, 65 per cent had almost complete clearance. But at what cost? With long term use cyclosporin causes hypertension and nephrotoxicity (kidney damage).
French doctors writing in the New England Journal of Medicine (13 June 1991) reported that cyclosporine therapy results in frequent neurological complictions, including coma and convulsions. Because of its toxicity, its use is restricted to hospital dermatologists.
Topical steroids such as Dermovate have adverse effects from excessive use such as harm to the adrenal glands, and serious flare ups after withdrawal. Most UK dermatologists reserve them for special circumstances (A J G McDonagh, Rupert Hallamshire Hospital, Sheffield, The Lancet, 31 August 1991). Dermovate, the steroid of steroids, should only be used for a short course of a month or more. Glaxo, its manufacturer, warns against using the drug on the face for more than five days, since longer use might cause “atrophic changes”, that is, wasting of the tissues. Avoid usage around the eyes, because it can cause glaucoma. Glaxo goes on to warn that topical steroids in general can cause rebound relapses, create tolerance, spark off generalized “pustular psoriasis” and cause a local or systemic toxicity “due to impaired barrier functions of the skin”. In other words, the drug itself may create a vicious cycle which causes your psoriasis to worsen.
Fish oil . Lower incidence of psoriasis among Greenland Eskimos, attributed to the mainly fish diet, high in omega 3 fatty acids, sparked clinical trials which have shown an improvement with the addition of fish oil to the diet. (Geraldine McCarthy, Medical College of Wisconsin, The Lancet, 28 September 1991).
Dithranol. (Cignolin in Europe, and Anthralin in the US) remains the most effective topical treatment, and has been the mainstay of topical treatments for 65 years. It should not touch normal skin as it causes irritation. Strengths should be increased from 0.1 up to 1 per cent if tolerated. Initially the cream should be left on for half an hour, but this can be increased to one to two hours. It cannot be used on the scalp and face. (GP Clinton Hale, MIMS Magazine, 15 August 1991).
However, it causes a brownish purple staining of the skin; bandages are required and clothes and bedding become ruined as the stains cannot be washed out. It can burn off the top layer of skin if the strength is not carefully controlled. A new Dithranol stick makes application easier.
Coal tar shampoo for mild scalp conditions. Coal tar (Alphosyl) lotion or cream in moderate scalp conditions.
White soft paraffin for five or fewer lesions. Emollients added to the bath can soften plaques.
Ultraviolet light B can be given twice weekly for two months. It claims to clear generalized plaque in 85 per cent of patients. Main disadvantages are that the patient has to attend hospital, and the risks include phototoxic reactions, increased photoageing and an increased incidence of skin malignancies. A UVA unit will not help; that is for tanning only.
PUVA (psoralen + UVA). As above, but patient is given psoralen tablets (a photosensitizing drug) two hours before the body is irradiated and has to wear protective glasses for 24 hours afterwards. However, there is an increased risk of genital tumours (Stern et al, NEJM, 19 April 1990).
Methotrexate (Maxtrex) is a maintenance treatment for extensive psoriasis when resistant to topical treatment. Not for pregnant women or people with liver disease, significant renal impairment, bone marrow suppression or excessive alcohol consumption (some say no drinking at all should be allowable). Main side effect is liver fibrosis. Other side effects include nausea, indigestion, loss of appetite, abdominal pain, fatigue, ulcers, haemorrhaging and hair loss. Used since 1955 to treat psoriasis, it is better known for its use to treat cancer, including leukaemia and Hodgkin’s disease, and is also sometimes used to reduce the risk of kidney rejection after transplant.
Synthetic retinoids are related to vitamin A and are useful in extensive plaque psoriasis. However, side effects include raised cholesterol, hepatitis, hair loss and skin fragility. Patients can also experience dryness and irritation of the eyelids and lips, and skin thinning .
Benoxaprofen has been withdrawn because of serious side effects, but the British medical authorities have approved a limited number of trials with psoriasis.