Three ways to deal with psoriasis

Medical Matters/Dr Muiris Houston: A recent letter from a psoriasis sufferer had this to say: "I'm more or less living with …

Medical Matters/Dr Muiris Houston: A recent letter from a psoriasis sufferer had this to say: "I'm more or less living with my psoriasis, but yesterday on the train to Dublin I met a young woman on her way to hospital . . . . Her fare to Dublin is costing her €30 each time she goes for treatment. If she could get into [our local clinic] she would be spared that cost."

Asking if I could highlight the €90 the young woman has to spend on transport for a typical week's treatment, she asks: "Could you tell the Minister for Health how much it annoys us to hear him say, when challenged, 'I've given X billion this year,' when what he should be saying and doing is concentrating on people and how to improve life for them?"

It is a well-made point, although of the recent crop of health ministers, Micheál Martin is generally regarded as a most caring man. The problems we now see in the health service are the result of years of chronic underfunding. It will take 10 more of sustained effort, money and realignment to make the system more inclusive and caring. Unfortunately, at the last Budget, the additional funding that had begun to flow was abruptly cut off.

But back to psoriasis. This relatively common skin condition - it affects 2 per cent of the population - can occur at any age but usually starts in adolescence and early adult life. Although its cause is not fully understood, we know genetic factors are important. If one parent has the disease, there is a 10 per cent chance that a child will develop psoriasis.

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The condition causes dull, red and scaly plaques on the skin. It typically affects the front of the knees and the back of the elbows. The sacrum - the lower back below the lumbar area - and the scalp are other common locations. Referred to as chronic plaque psoriasis, its salmon-pink colour and scaly appearance are unmistakable.

A form of the disease called guttate psoriasis, most often seen in children and teenagers, involves the sudden eruption of small but widespread psoriatic rash. Often precipitated by a streptococcal throat infection, the flare-ups can also be caused by infection with HIV. Some children with guttate psoriasis develop the chronic plaque version of the skin ailment. Other trigger factors include alcohol and smoking. Although most cases improve on exposure to sunlight, in 10 per cent the rash gets worse. There are also a number of known drug triggers, including oral steroid medication, lithium (used in the treatment of bipolar depression), beta blockers and non-steroidal anti-inflammatory drugs.

As well as affecting the skin, psoriasis spreads to the nails in 50 per cent of sufferers. The initial sign is a pitting of the nail, followed by thickening and curling in more extreme cases.

The first line of treatment for chronic plaque psoriasis involves emulsifying ointments. These help to moisturise the plaques and reduce scaling. A mix of white soft paraffin and liquid paraffin still has a place in treatment, despite the availability of more modern emulsifying ointments and aqueous creams.

Once the psoriasis is stable, patients can opt for one of three treatments. For those who don't mind its odour, tar remains a good option; it is available commercially and can also be made up by pharmacists, by mixing with soft paraffin or emulsifying ointment.

A drug called calcipitriol (trade name Dovonex), which is an analogue of vitamin D, is available as a cream, ointment and scalp lotion to apply twice a day. Unlike other treatments, it does not stain the skin. It is important not to use more than 100 grams a week, to avoid the risk of elevated calcium levels in the blood. It should not be used on the face, in folds of skin or in the genital area.

Another treatment option is dithranol. Its main drawback is skin irritation. Doctors discovered that by limiting the treatment time to only 20 to 30 minutes, however, they can reduce the risk of irritation without interfering with the drug's efficacy. This treatment is called short contact dithranol therapy. Best for stable psoriasis plaques on the trunk and limbs, it must be applied accurately or surrounding areas of normal skin will be burnt.

The standard treatment for psoriasis of the scalp is Cocois ointment, made of coconut oil, coal tar, sulphur and salicylic acid.

These treatments will help most psoriasis sufferers. If more than 30 per cent of their skin is affected or initial treatment fails, however, then it is time to see a skin specialist, which is where the young woman travelling to Dublin was going. I will outline the more specialised psoriasis treatments in a future column.