Psoriasis

Overview:

Psoriasis is a chronic, recurring autoimmune disease characterized by red, thickened patches on the skin, often with silvery scales. It is the result of overproduction of the skin cells. Usually, cell turnover occurs roughly every 28 days, but in the case of psoriasis, this happens every few days instead, resulting in a thickening of the skin in the affected area.

Around 2% of the Western population are affected by psoriasis. Men & women are both equally affected. It is an inherited condition (runs in families) that is not contagious to others.

There are several types of psoriasis, including;

Plaque psoriasis (psoriasis vulgaris):

This is the  most common form of psoriasis, affecting around 80-90% of people with psoriasis. It is characterised by itchy, thickened, red plaques with overlapping silvery scales. Common areas affected include elbows, knees & trunk although any area of the body can be affected.

Guttate psoriasis

Also known as eruptive psoriasis, guttate psoriasis is often triggered by a streptococcal throat infection.  It is characterised by small, salmon coloured drop like plaques over large areas of the body.  It is most commonly seen in children.

Pustular psoriasis

Also known as palmoplantar pustulosis (PPP), pustular psoriasis is a rare form of psoriasis characterised by a number of white pustules (pus filled blisters) surrounded by red, inflamed skin. Most commonly affected areas are the palms of the hands & the sole of the feet although other parts of the body can also be affected.

Flexural psoriasis

Also known as inverse psoriasis, flexural psoriasis occurs on areas of the body with folds such as the armpits, folds of the abdomen, breasts, between the buttocks, genitals etc. It appears as smooth areas of red plaques with a clearly defined border, a crack within the crease may also be present. This is different to the typical psoriasis symptoms of thickened, silvery scaling. Secondary fungal infections cause by candida albicans may occur in some patients. 

Erythrodermic psoriasis

Also known as Psoriatic erythroderma, erythrodermic psoriasis is a generalised & rare form of psoriasis in which widespread areas of the body (85% or more). Typical symptoms include redness, inflammation, thickening & scaling of the skin along with severe itching. Swelling & pain may also be present.

Erythodermic psoriasis is a result of unstable psoriasis, it is an extremely serious & medical attention must be sought immediately.

What causes psoriasis?

Psoriasis is thought to be an immune based condition which is runs in families. The immune system is made up of organs & cells, its role is to defend the body against foreign invaders such as bacteria, viruses, fungi & parasites. Some people develop auto-immune diseases in which the immune system turns on itself. Psoriasis is one such condition.

Normally the skin cells are continually being shed & renewed approximately every month (this is known as cell turnover), however cell turnover is much more frequent in people with  psoriasis.

Despite being an inherited condition, not everybody who carries the gene mutation(s) will develop psoriasis. Certain  factors may cause or trigger a psoriasis outbreak. These triggers may include;

• Smoking

• Stress

• Infection (Streptococcal infections, fungal infection,

• Skin injury (scratch, insect bite, sunburn etc). This is known as Koebner phenomenon.

• Certain medications (including beta-blockers, lithium, anti-malarial medication etc)

• Weather (sun exposure, cold/dry winds)

• Alcohol

• Sudden withdrawal of oral corticosteroids

• Idiopathic (no known cause)

Psoriasis symptoms:

Psoriasis is a chronic condition & people will experience outbreaks & then periods free of symptoms. Symptoms vary depending on the type of psoriasis, but common symptoms include;

• Itching.
• Thickened, scaly, silvery plaques.
• Redness.
• Knees, elbows & scalp are most commonly affected areas although it can occur anywhere on the body.

Psoriasis treatment:

There is no cure for psoriasis, however it can be managed effectively with the following;

Topical treatment:

For mild to moderate cases, keeping affected areas well moisturised is important. Common treatments include;

• Emollients (moisturising creams, ointments)

• Topical steroids

• Tar preparations

• Vitamin D derivatives. Calcipotriol (Dovonex), calcitriol (Silkis) or tacalcitol (Curatoderm).

Systemic treatment:

Moderate to severe cases that can't or haven't responded to the above methods may require systemic medicines. These include drugs that suppress the immune system.  Common medications include;

• Methtrexate

• Cellcept (Mycophenolate Mofetil)

• Ciclosporin (Neoral)

• Acitretin (Soriatane)

• Hydroxurea

For detailed information on the above medications, read here.

While great care has been made in the creation of these articles, we cannot guarantee the accuracy or omissions on these pages. If in any doubt whatsoever, seek professional medical advice.