Psoriasis is a fairly common condition, with approximately 2% of adults affected. While the cause isn’t precisely known, the result is skin that grows around seven times more quickly and thickly than it should.

The patches – also known as plaques – can appear anywhere, but most frequently affect the elbows, knees, lower back and scalp. In cases where the groin, armpits, genital area and/or skin between the breasts are involved, the patches will generally be less scaly and instead have a glazed appearance. Psoriasis does not result in scarring, and rarely results in hair loss.

Psoriasis is not an allergy, and it is not contagious. Your patches of affected skin can grow and shrink for no apparent reason – but even if it disappears completely, the predisposition remains. Recurrent flares can happen years after the first incidence.

Different cases need different solutions. But there are some basic principles that psoriasis treatment will aim to achieve:

• Softening the psoriatic patches
• Protect skin from irritation
• Reduce itching, scaling, thickness and redness
• Immune system suppression (in severe cases)

It is generally believed that psoriasis is due (at least in part) to an abnormal immune system reaction against a component of the skin. The precise cause of this is unknown, but there is definitely a genetic component. Some families have a propensity to developing the condition; about half of those affected know of a relative with psoriasis too.

Outbreaks seem to start after a trigger of some kind – from emotional stress to skin injury, strep throat to hormones, or in some rare cases, specific medications. Excessive alcohol consumption does not itself trigger psoriasis, but it can certainly aggravate the condition.

Certain treatments are more appropriate for some patients than others. The following are loosely arranged from basic treatments for mild cases, through to more intensive regimens for severe cases.

• Many patients experience dramatic improvement of their symptoms during sunny holidays. You must take care, however, as in addition to the widely-known risks associated with excessive sun exposure (premature aging and skin cancer), there is also the risk of developing psoriasis in sunburned areas.

• A bath with bath oil or a tar solution can help soften affected skin and lift the scale. Make sure the water is warm, not hot, and that you use gentle, bland soaps or soap substitutes. Avoid using detergents and antiseptics – they are unnecessary and may irritate your skin further.

• Emollients/moisturisers. You may be prescribed or suggested medicated creams – but if not, it is wise to keep the psoriasis soft to prevent cracking and pain. Vaseline, emulsifying ointment and Sorbolene cream are all good options.

• Occlusive dressings. If your psoriasis plaques are quite small, using waterproof adhesive dressings may help them improve.

Scalp care

• Basic scalp care. For mild scalp involvement, medicated shampoos can be purchased from a chemist. Coal tar is a key ingredient, while ketoconazole shampoo can be helpful at times. For best results, you should rub the shampoo into your scalp very thoroughly, leave for 5 to 10 minutes, then reapply. While safe for daily use, using these shampoos more than twice a week may result in irritation. If you dislike the smell, follow up with a regular shampoo and conditioner.

• Scalp applications. More severe scalp involvement will require dedicated scalp applications. Alcohol based products are easy to use, but can sting, while steroid lotions can reduce itching but are less effective when it comes to lifting scale. Creams with salicylic acid and coal tar are very effective, but they are messy to apply. You should leave the treatment on for several hours and shampoo it off later ­– many people apply it at night and wash it out in the morning. In these severe cases, scale can build up again quickly, so daily application of the cream may be necessary.

• Crude coal tar. Coal tar has proved an effective ingredient for many years, and it can be used in intensive in-hospital regimes as well as a self-administered treatment when in its refined form. The ‘Goeckerman’ regime takes place in hospital, with coal tar applied to the patches after the skin has been exposed to ultraviolet light. This is highly effective, with the psoriasis clearing in 4 to 6 weeks. For at-home use, refined coal tar is used in various creams, ointments and gels. It may sting when applied to affected skin, but most patients find it helpful. It’s important to note that you should never apply coal tar or pine tar immediately before sunbathing, as this could result in a severe burn.

• The ‘Ingram’ regime is another in-hospital regime, in which dithranol is applied twice daily to the skin. It works more quickly than coal tar, but it’s more difficult to use. If you have very fair skin, this will not be the appropriate treatment for you. It requires very precise application, so it’s only suitable for large patches of psoriasis. ‘Short contact dithranol’ is a suitable self-administered option, in which you must apply the preparation to the patches of psoriasis for 10 minutes only. It will stain the skin a brown colour, and may be irritating.

• Topical steroids. Steroids may be a better option for some patients, as they are clean and soothing. Large areas of plaque or delicate locations (like the face, armpits and groin) are best suited to weaker steroids such as hydrocortisone. Often these will be combined with an antifungal agent to combat thrush). For small patches of affected skin, stronger topical steroids can be used, but tread carefully. They should only be used for limited time periods, and you need to be aware of possible side effects, such as skin thinning, which leads to broken capillaries and stretch marks and can aggravate psoriasis over the long term. Finally, very powerful topical steroids are the most effective – but in turn, they carry with them the chance of more serious side effects. Make sure that you limit how long you use them for (daily use for no more than two weeks out of every two months, or alternatively twice weekly in the long-term) and take care not to use them in delicate areas (face, armpits and groin). Unless your specialist advises you differently, never use more than 50g a month.

• Vitamin D-like compounds. Calcipotriol ointment/cream is safe and effective in cases of mild to moderate psoriasis, provided you don’t use more than 100g per week. In some cases, applying calcipotriol twice a day can clear psoriasis within 6 to 8 weeks. In most cases, though, the ointment or cream will lessen itching, scaling, thickness and redness. Be aware that one in five patients may experience irritation from calcipotriol, such as a facial rash, but often this will diminish with continued use.

Radiation

• Ultraviolet radiation (PUVA). PUVA is also known as photochemotherapy, and consists of UVA radiation as well psoralens, a specifically useful compound that lessens the amount of UVA radiation required in order to be effective. The same risks arise as with UVB treatment, but because it is straight-forward and often very successful, it’s a popular option.

• Oral medication. Oral medication is currently only used in very severe circumstances. This could be very extensive psoriasis (40% or more of the body surface affected) or psoriasis that significantly affects function (such as on the palms, preventing work, or on the feet, preventing walking). All of these have potential side effects and risks, which your dermatologist will carefully explain to you. Feel free to ask any questions about these or any medications that are proposed – we’re here to make you feel secure in your skin health journey.

• These tablets are taken weekly, and generally will result in a dramatic improvement of symptoms. Methotrexate can cause nausea, and regular blood tests are necessary. The drug can cause liver damage if it is taken for an extended period of time – blood tests will track this, but you should also avoid alcohol to ensure that the liver is not unnecessary aggravated.

• Acetretin is similar to vitamin A, and can lead to slow improvement. Side effects can include dry lips, peeling palms and soles, thinning hair, tiredness and muscle pains. Usually these are related to being on an incorrect dose, but we will make sure you have regular blood tests to stay on top of everything. Liver damage is a risk, and pregnancy must be strictly avoided while on acetretin, and for at least three years afterwards.

• Cyclosporin is an immune-suppressant, and will only be enlisted for the most severe of cases. It is highly effective, but carries risks of raised blood pressure and kidney damage – so if you are on cyclosporine, we will monitor you carefully.

• “Biological agents” e.g. Etanercept and Adalimumab. These are the latest treatments for severe psoriasis. They are extremely effective with minimal side effects. Biological agents have revolutionised the management of psoriasis and has literally given thousands of chronic psoriasis sufferers a new lease in life. They are fully subsidised by Pharmac provided that certain criteria are met.