Everything you need to know about psoriasis

Psoriasis is a common, inflammatory skin condition, which affects around one in 50 people in the UK. It is caused by an overproduction of skin cells and is a chronic (long-term) condition, with alternating periods of no or mild symptoms followed by more severe symptoms called flare-ups.

What happens to skin with psoriasis?

In healthy skin, new skin cells are produced every three to four weeks to replace old skin cells. In individuals with psoriasis, new skin cells are made much more quickly, roughly every three to seven days. 

These new cells are not yet fully mature and build up on the surface of the skin. This causes patches of scaly skin to develop, which can appear red or pink on light skin and purple or dark brown on dark skin. 

The immune system is also involved in psoriasis. Although its exact role isn’t fully understood as yet, T-cells are known to be involved. 

In a healthy body, these immune cells recognise and attack germs, such as harmful bacteria. However, in psoriasis, these T-cells mistakenly attack your own skin cells, which is why psoriasis is suggested to be an autoimmune condition. 

Who is at risk of psoriasis?

Psoriasis is not contagious. Your risk of developing the condition, therefore, depends on whether you have a family history of the condition as well as environmental factors. 

Psoriasis can be triggered by hormonal changes, infection (eg streptococcal throat infection, bronchitis, Helicobacter pylori stomach infection), injury to your skin, stress, exposure to too much sunlight, taking certain medications (eg beta-blockers, nonsteroidal anti-inflammatory drugs (NSAIDs) and tetracyclines), smoking and drinking alcohol. 

Although psoriasis can develop at any age, it usually develops in your twenties and thirties or in your late forties and fifties. 

Psoriasis symptoms

Psoriasis causes itchy, scaly, thickened patches of skin to develop, usually on the outer sides of your elbows and knees, scalp and sometimes genital area. However, the more severe your psoriasis, the more likely patches will additionally develop elsewhere on your body. 

The appearance of these patches can affect your self-esteem and consequently, you may find that you limit your social activities, which can have knock-on effects on your relationships. 
Around half of individuals with psoriasis also develop pitting and/or ridging of the nails. 

If you are concerned that you may have psoriasis, see your GP for advice and diagnosis. A diagnosis can usually be reached by examining your skin, including the distribution of affected areas, and asking about your family history, symptoms and duration of your symptoms.

Types of psoriasis

Psoriasis can be grouped into several different types. The three most common types are plaque psoriasis (psoriasis vulgaris), guttate psoriasis and inverse (flexural) psoriasis. Less common types of psoriasis include pustular psoriasis and erythrodermic psoriasis.

Plaque psoriasis 

This is the most common type of psoriasis. It causes itchy, scaly thickened patches of skin that usually appear symmetrically across the body, most commonly on the outer sides of the elbows and knees, scalp and lower back.

Guttate psoriasis 

This is more common in children and young adults and usually develops after a streptococcal throat infection. Its appearance is different from plaque psoriasis, causing small, drop-shaped sores on the chest, arms, legs and scalp. 

Guttate psoriasis usually disappears after a few weeks, but in some cases, it can develop into plaque psoriasis. 

Inverse (flexural) psoriasis

This type of psoriasis develops in the folds or creases of your skin, such as in your armpits, groin, between your buttocks or under your breasts. It causes large, red patches of skin to develop in these folds; these patches are usually smooth.

Friction (rubbing) and sweating make inverse psoriasis worse. 

Pustular psoriasis

This causes pustules (blisters filled with pus) surrounded by red skin to appear on your skin. Although it most often develops on the hands and feet, it can occur anywhere on your body. 

Erythrodermic psoriasis

This is a rare but severe type of psoriasis that causes itchy, scaly skin to appear over most of your body. 

It usually occurs in individuals who have another type of psoriasis that is poorly controlled and can be triggered by certain medications or sunburn. In some cases, emergency treatment is needed. 

Health risks of psoriasis

Severe cases of psoriasis can lead to psoriatic arthritis, where the joints become inflamed, swollen and painful. 

This can cause your joints to become loose or crooked, and the bone at the ends of your joints to wear down. It is usually the small joints of the fingers and toes that are affected but larger joints in the neck can also develop psoriatic arthritis. 

Severe cases of psoriasis are also linked to a higher risk of metabolic syndrome, which refers to a group of health problems that increase your risk of cardiovascular disease and type 2 diabetes. 

Treating psoriasis

Although psoriasis cannot be cured, it can be controlled to improve your quality of life.

Treatment focuses on reducing how quickly your skin produces new skin cells. This can be achieved through topical treatments ie applying corticosteroid creams and vitamin D3 analogues. 

If topical treatments aren't effective, your doctor may recommend systemic treatments, which are applied more broadly, such as phototherapy, oral medication or injections. 

Phototherapy exposes your skin to specific wavelengths of ultraviolet light in a controlled way — this slows down the production of new skin cells.  

In the most severe cases of psoriasis, biologic treatments may be prescribed, usually as injections. These interfere with the chemical signals that cause the symptoms of psoriasis. 

Living with psoriasis

Psoriasis is usually a lifelong condition. To minimise the impact on your quality of life it is important to take good care of your skin. This involves regular moisturising, avoiding triggers of your symptoms and taking any medication prescribed by your doctor as instructed.

In terms of medication, a dermatologist can discuss the most suitable treatment options for your particular circumstances.  

It is also equally important to make sure you have the emotional support you need to cope with the mental and physical challenges of living with psoriasis. 

Psoriasis can affect the way you approach social interactions, relationships, hobbies and your daily activities. If you’re concerned that you’re not coping well, speak to your GP about mental health support. 

You can also find support and useful resources from the UK’s Psoriasis Association and The Psoriasis and Psoriatic Arthritis Alliance.