Psoriasis and other disease & lifestyle issues
PSORIATIC ARTHRITIS
Sometimes, people with psoriasis experience pain and swelling of some of their joints, typically the ends of their fingers and toes. When psoriasis and arthritis occur together, the resulting condition is called psoriatic arthritis.
The true incidence of psoriatic arthritis is unknown, because it depends on which population of psoriatic patients is investigated. In a hospital setting (where more severe psoriasis is likely to be under study) the prevalence of arthritis in patients with psoriasis is six to eight per cent (compared with 0.7 per cent in a control group with other skin diseases). Psoriatic arthritis is more common in women than in men, with a peak onset in the 40to 60-year age group. Psoriasis starts before the arthritis in 65 per cent of cases, whereas the arthritis precedes the psoriasis in 19 per cent of cases; they occur at about the same time in 16 per cent.
There are several different patterns of psoriatic arthritis:
• You may find that the small joints of your fingers and toes are affected, particularly if you have severe nail psoriasis – this is the classic and typical psoriatic arthritis, and tends to occur only in people with psoriasis.
• You may have a rheumatoid arthritis pattern in your hands and feet. A blood test can help to differentiate between rheumatoid arthritis and psoriatic arthritis. In rheumatoid arthritis, a specific chemical in the blood known as rheumatoid factor is high, whereas, in psoriatic arthritis, it is low.
• You may get one or several joints involved on either side of your body. This may be the result of a rare form of particularly debilitating arthritis in which joints of your fingers and toes become permanently deformed and are unable to function.
• You may have arthritis of the spine, characterised by a stiff, painful lower back with pain on both sides where the sacroiliac joint (at the back of your pelvis) is found.
TREATMENT
The treatment of psoriatic arthritis is similar to the management of rheumatoid arthritis. A variety of drugs is used.
• Non-steroidal anti-inflammatory drugs (NSAIDs), which suppress inflammation and relieve the pain and swelling of the joints. NSAIDs do not halt the progression of the disease. They are called ‘non-steroidal’ to distinguish them from corticosteroids, which also have anti-inflammatory properties.
• Sulphasalazine (a sulphur-based drug) and gold compounds, which dampen down inflammation and halt the progress of joint diseases.
• Methotrexate, which interferes with cell division and slows down the epidermal cell turnover.
• Azathioprine, an immunosuppressive drug that dampens down inflammation associated with arthritis.
• Ciclosporin A, which also suppresses the immune system and treats both the psoriasis and the arthritis.
• Biologics.
OUTLOOK
Psoriatic arthritis usually causes less pain and disability than rheumatoid arthritis. It should improve with treatment, although the joint problems may recur at any time without warning. The outcome may be very hard to predict.
HIV AND AIDS
Occasionally, patients with AIDS develop particularly severe psoriasis. Many of the treatments for psoriasis, such as methotrexate, PUVA and ciclosporin A, may not be suitable, because immunosuppressive therapy is harmful to these already immunocompromised patients. Retinoids and zidovudine (AZT) are both effective drugs and safer to use.
PSORIASIS IN RELATION TO ALCOHOL, SMOKING AND DIET
There appears to be a link between excessive alcohol intake and psoriasis. Research shows that men with psoriasis are more likely to be heavy drinkers than the rest of the male population, but this does not seem to be the case among women. Whether excess alcohol could actually cause psoriasis in men is far from clear. It would be quite understandable if people with psoriasis turned to drink more than usual because of the stress of having an unpleasant skin condition.
In very high doses, alcohol damages the liver. Many of the systemic treatments for psoriasis are best avoided in patients with liver disease (methotrexate, for example), so it is important that people with psoriasis keep their alcohol intake to sensible levels. Otherwise, many effective systemic agents that may have been able to control their psoriasis will not be suitable for them.
Smokers are at an increased risk of pustular psoriasis of the palms and soles and of chronic plaque psoriasis. This is thought to result from the harmful effects of smoking on the immune system.
The role of diet in psoriasis management seems to be of little importance, although eating a balanced diet with plenty of fresh fruit and vegetables will help to keep you in general good health. However, if a person is obese and psoriasis involves the flexures, then losing weight may help, because chafing of layers of fat under the belly or under heavy breasts may lead to particularly persistent plaques.
