Psoriasis
What is it? Psoriasis is caused by over-activity of the skin's normal surface cell replacement process. Normally, the surface skin cells shed and are replaced every 21-40 days. In psoriasis, the new cells are made more quickly, before the old ones have been shed. This results in patches of skin that are raised, red and coated with silvery scales.

What causes this?
Psoriasis is not due to an infection and cannot be caught from another person. It can't be transferred from one part of the body to another. Psoriasis can develop at any age, and men and women are equally likely to be affected.

Psoriasis can run in families, but commonly arises in people with no previous family history. The precise cause of the condition isn't known, but it has been observed that it can be triggered by injury, sore throats, chest infections, certain drugs, or any kind of emotional or physical stress. Pregnancy is known to improve the symptoms of psoriasis, as is exposure to sunlight.

What treatments are available?
The latest cream-based treatments are closely related to Vitamin D. They are often preferred because they are odourless, do not stain the skin or clothes, are easy to apply, and produce very little irritation in the majority of users. For patients with more severe psoriasis, there are two other treatments that can be used under specialist supervision.

PUVA is a light therapy. A chemical is applied to the psoriasis plaques, and then the skin is exposed to controlled amounts of ultraviolet radiation, UVA. Severe psoriasis can be treated with an oral medication called methotrexate. This drug is also used to treat certain forms of cancer. It attacks rapidly dividing cells, so targets the overactive skin cells that are developing. This drug requires careful monitoring with blood tests, as it is very toxic.

There has also been the recent launch of a new drug called Raptiva®, described as a treatment option that can be easily integrated into a patient's life. It involves self-injections which offer an alternative to time-consuming topical applications. Clinical trials of Raptiva® involving 3,500 patients in the US and Europe have initially shown positive results and the drug has been given the okay for use by adult patients with moderate to severe symptoms in all 25 EU countries, the USA, Mexico, Australia and Argentina.

Eczema
What is it? Eczema and dermatitis are both medical terms to describe a skin inflammation that causes redness and intense itching.

What causes it? Occasionally, eczema is due to an external irritant such as lathe oil or chemicals used in detergents, etc. This is also described as irritant dermatitis. However, the most common type of eczema, especially in children, is atopic eczema. This is a genetic disorder, and is closely associated with asthma and hayfever. The skin in sufferers of atopic eczema is hypersensitive, and reacts to many different environmental allergens, such as pollens, animal hair, feathers and house-dust mite.

Some eczema sufferers, particularly children, can react to certain foods, especially eggs and dairy products. The eczema triggers vary from one sufferer to another and may change over time, which limits the value of allergy testing for many sufferers.

In addition to the allergic triggers, people with atopic eczema often have a flare-up in response to everyday chemicals such as biological washing powder, fabric conditioner, bubble baths etc, because the skin is unusually sensitive. Synthetic or woollen fabrics can also aggravate the skin.

What treatments are available?
Avoidance of allergens and likely irritants is a very important part of any treatment plan. It is best to avoid or limit contact with furry pets, especially cats and dogs, and take measures to minimise house-dust mite exposure by keeping house dust to a minimum with regular damp dusting and vacuuming. Cotton clothing is best, and avoid biological detergents, fabric conditioners and scented toiletries, such as bubble baths and shower gels.

Emollients are the cornerstone of eczema care. These are products that moisturise and soften the skin, and also help to relieve the itching. They are safe, and should be used frequently in order to achieve the full benefits. Emollient oil should be used in the bath every day to treat underlying skin dryness. Showering is quicker and more convenient, but tends to dry the skin, and so should be done only when necessary, and always using a shower emollient to minimise the drying effect. An emollient cream such as aqueous cream should always be used as a soap substitute, as soap also dries the skin.

Emollient creams should be used liberally, at least twice daily, to all areas of dry skin. Their use should increase to at least four times a day if the eczema flares up. Steroid creams can be used for more resistant areas of eczema, but excessive use can thin the skin and cause damage, especially when used on facial skin or on a child. Tacrolimus is a recent development in eczema treatment. This cream can be used for moderate to severe atopic eczema under specialist supervision, and can be used in place of steroid cream in cases where there are worries about possible steroid-related skin damage. Antihistamine tablets can help relieve the itch.

Acne
What causes it? Generally speaking, acne is a hormonal condition. It is NOT caused by poor hygiene or eating too much chocolate or fatty food. Acne, of varying severity, affects around 70% of teenagers, starting in the early teens and reaching peak severity at around 17-21 if not effectively treated. It is usually gone by the age of 25, although persistent acne affects significant numbers of adults, and adult-onset acne is by no means an uncommon condition. In adults, acne may be triggered by pregnancy or hormonal contraception (pills, injections, implants and even the Mirena coil), and may be part of a more complex hormonal condition known as polycystic ovary syndrome (PCOS). Sometimes spotty skin is part of premenstrual syndrome (PMS), and in some people it is aggravated by stress.

What treatments are available? Antiseptic washes are widely advertised, but are unlikely to help a great deal. Mild acne can be treated with topical skin products containing benzoyl peroxide. Some of these are available over the counter at pharmacies, or on prescription. They may irritate the skin during the first few days of treatment, but this usually settles down within a week or two.

Alternative topical skin products include antibiotic lotions and vitamin-A preparations, both of which require a prescription. There are three different antibiotics available in topical form.

More severe forms of acne may need to be treated with antibiotic tablets. Again, several different types are available on prescription.

With all these treatments, improvement is not immediate, and it may take up to three months for significant benefit to be apparent. Treatment may need to continue for six to 12 months, or even longer.

Women with PCOS may be offered a hormonal treatment called Dianette to help with acne. It may also be offered to certain other women, especially if they also require a contraceptive pill, as Dianette also has contraceptive properties.

If acne is very severe, a consultant dermatologist can prescribe a drug called Roaccutane, which has proved to be the most effective treatment for the most severe forms of acne. Its use is restricted because of potentially serious side effects.