What causes psoriasis?
What is the treatment for psoriasis?
Psoriasis is a common skin condition caused by skin cells growing and dividing too rapidly. It's not exactly known why this happens, but it's thought that the immune system is involved. The immune system seems to attack healthy skin cells by mistake, causing a series of events that leads to excess skin cell growth. Psoriasis is not contagious. It cannot be passed from person to person.
Treatments for psoriasis fall into three categories:
- Topical treatments - applied directly to the skin or the scalp, such as creams and ointments. Topical treatments include:
- Emollients (moisturisers).
- Vitamin D-like chemicals (vitamin D analogues) such as calcipotriol.
- Topical steroids.
- Topical calcineurin inhibitors such as tacrolimus or pimecrolimus.
- Coal tar preparations.
- Salicylic acid.
- Light therapy - treatment that uses ultraviolet light in a controlled way on the skin. Light therapy comes in two forms:
- Psoralen plus ultraviolet A (PUVA).
- Ultraviolet B (UVB) phototherapy.
- Systemic therapy - medicines taken as tablets or given as injections. These mostly work on the immune system. Systemic therapy for psoriasis includes:
Most people with psoriasis can manage the condition with topical treatments alone. When these don't work, or if the psoriasis is severe, they might be referred to a dermatologist to move on to stronger treatments.
The rest of this feature will take an in-depth look at the treatment of psoriasis, as, at Patient, we know our readers sometimes want to have a deep dive into certain topics.
What is the treatment for psoriasis?
There are many different treatment options for psoriasis. Choosing the right ones depends on:
- Where the psoriasis is on the body.
- How severe or widespread the psoriasis is.
- Which type of psoriasis is present - see psoriasis symptoms for more detail.
- People's preferences for treatment, including how acceptable the side-effects are, and how easy they find each treatment to use.
- Which treatments have been tried already.
Psoriasis treatments can be divided into:
- Topical treatment - the main treatments for psoriasis. For most people, topical treatment is enough to get their psoriasis under good control.
- Light therapy - a specially-delivered ultraviolet light therapy given to the skin.
- Systemic therapy - tablets or injections.
Topical treatments are important for the treatment of psoriasis. There are many different medications, which come in various forms. Different forms are suitable for different body areas, and feel different when they're applied. They can also work differently. For example, greasy emollients (moisturisers) usually work better to protect and moisturise the skin, but are often unpleasant to put on compared to more watery, lighter, emollients.
Topical treatments can come in the following forms:
- Lotions - thin and water-based and feel light on the skin.
- Creams - a mixture of water and oils, thicker than lotions.
- Ointments - mostly oil-based, thicker than creams.
- Gels - usually water-based, usually thinner than ointments, and tend to dry on the skin, leaving the active medicine behind.
- Foams - liquids with bubbles in them. Some people find these easier to apply than ointments or creams.
- Shampoos - liquids designed to be massaged into wet hair and scalp, left on (according to instructions), and then rinsed off.
- Scalp applications - thin liquids designed to be applied directly to the skin of the scalp.
- Medicated plasters or tape - medicine-containing fabrics that are stuck directly onto the skin and left (according to instructions) for a certain amount of time before being taken off.
Topical treatments for psoriasis include the following, many of which come in those different forms:
- Emollients (moisturisers). Areas of psoriasis tend to be dry, scaly, and sometimes cracked. Using lots of emollients regularly helps to keep the skin well-hydrated and protects it from further damage. They can help to relieve symptoms of itch and discomfort. They can also reduce the amount of scale on the skin. Emollients are safe. They can, and should, be used long-term, even when the skin is clear, to keep it healthy.
- Emollients contain oils, which are potentially flammable. Be very careful near naked flames, including people who are smoking. Avoid smoking whilst using emollient and especially avoid smoking in bed.
- Vitamin D-like chemicals (analogues). These seem to affect the way in which skin cells grow in areas of psoriasis, as well as reducing inflammation. Examples include calcipotriol (Dovonex), calcitriol (Silkis), and tacalcitol (Curatoderm). These are safe and easy to use. They can be used long-term. Side-effects include skin irritation, particularly in sensitive areas such as skin folds and the genitalia.
- They are generally avoided in women who are trying to conceive, or are pregnant, because of concerns that excessive vitamin D levels could harm the fetus. This is precautionary. Because there is more evidence for safety of other topical treatments in pregnancy, different treatments are usually preferred instead.
- Topical steroids. These are used for lots of other skin conditions as well, including eczema. Topical steroids work by reducing inflammation in the skin. Topical steroids come in different strengths - from mild to super-potent - and the strength has to be matched to the area of the body they're being used on. For example, thick skin, such as on the hands and the feet, usually needs potent or super-potent topical steroids - whereas thin skin, such as on the genitals, skin folds, or face, needs mild or moderately-potent steroids. Side-effects of topical steroids include skin thinning, hair growth, easy bruising, and visible blood vessels on the skin. As long as the right strength of steroid is used, and it's not used for too long, these side-effects are unlikely. Topical steroids are usually recommended to be used for a maximum of four weeks at a time, with a four-week break in between courses. Sometimes, doctors will recommend using them for shorter or longer periods of time.
- Topical calcineurin inhibitors, such as tacrolimus or pimecrolimus. These block a chemical called calcineurin in the immune system to reduce skin inflammation. They can be useful as an alternative to topical steroids, especially where the skin is thinner and more vulnerable to side-effects from long-term steroid use, such as on the face and in skin folds.
- Coal tar preparations. Coal tar is a thick oil that's been used for centuries to treat psoriasis. It reduces inflammation in the skin and helps to reduce scale on the skin. Coal tar comes in lots of different forms, including ointments and shampoos. It's most commonly used to treat scalp psoriasis in shampoo form - for example, Alphosyl 2 in 1, Capasal, and Polytar Scalp - but can be used to treat psoriasis on the body instead. Historically, coal tar preparations used to be sticky, smelly, and messy. Modern preparations are easier to use. Coal tar still has a distinctive smell, which some people dislike.
- Salicylic acid. This can be used to help to reduce very thick areas of scaling on the skin. It works by causing the outer layer of skin to shed acting as a scale lifter, helping to soften and remove psoriasis scales.
- Dithranol. This treatment has been used for more than a hundred years. It reduces over-production of skin cells and reduces inflammation in the skin. It can be useful for difficult-to-treat areas of psoriasis. However, it's time-consuming to apply. Dithranol stains the skin purple or brown, although this disappears from the skin slowly after stopping the treatment. It also needs to be carefully applied to areas of psoriasis, as it can irritate normal skin. Dithranol also stains fabrics and surfaces, so it's best to wear old clothes whilst it's on the skin, and to rinse baths and showers straight after using them. Because dithranol is difficult to use, it's fallen out of favour and isn't used much now. It's also quite difficult to get from pharmacies, as one of the manufacturers has stopped making it.
- Combination treatments. Some treatments contain combinations of medicines, and these can be really useful for getting psoriasis under control quickly. For example, Enstilar foam, Wynzora cream, and Dovobet gel or ointment all contain a combination of a vitamin D analogue and a topical steroid. These are often used as a first-line treatment for plaque psoriasis.
Topical treatments are usually enough to treat mild to moderate psoriasis. If they don't work, or for severe psoriasis, other treatments can be offered by a dermatologist.
Light therapy uses controlled amounts of ultraviolet light to treat psoriasis. It's given in two ways:
- Psoralen plus ultraviolet A (PUVA) - involves giving a chemical called a psoralen, as a tablet, gel or cream, or in bath water. Ultraviolent A light is then used on the skin - the psoralen makes the skin more sensitive to UVA.
- Ultraviolet B (UVB) therapy - involves exposing the skin to a controlled amount of ultraviolet B light.
The UK's National Institute for Health and Care Excellence (NICE) recommends that UVB therapy be used for people with plaque or guttate psoriasis when topical treatments haven't worked. PUVA can also be used for localised pustular psoriasis.
Light therapy - like any exposure to sunlight - increases the risk of skin damage that can, eventually, lead to skin cancer. Dermatologists usually advise a limit on the number of treatments to reduce the risk of this happening.
Systemic therapy - treatment that affects the whole body - includes tablets and injections. Systemic therapy can only be given by a dermatologist. These are used for moderate or severe psoriasis where topical treatments and UV therapy haven't worked. Systemic treatments - with the exception of acitretin - work by suppressing the activity of the immune system. They require specialist monitoring to be used safely. Some systemic treatments are known to cause serious problems to unborn babies - for others, there is only limited data on how safe they are in pregnancy. They are therefore generally not used in pregnancy. Women using a systemic treatment will usually be advised to avoid becoming pregnant, or to stop the treatment if they do want to become pregnant.
Systemic therapy might also be given for psoriatic arthritis.
Systemic therapies include:
- Methotrexate. This comes as a tablet and also an injection, and is usually taken once a week. It requires regular blood test monitoring. It can cause serious problems to unborn babies, so pregnancy must be avoided whilst taking it - and for up to six months after stopping.
- Ciclosporin. This comes as a tablet or a liquid. It's usually used for short periods - three or four months. It requires regular blood test monitoring. It can be used in pregnancy, but the benefits and risks need to be carefully considered in each individual case; speak to your specialist for more information.
- Acitretin (Neotigason). This comes as a capsule. Unlike the other systemics, this doesn't work on the immune system, but instead seems to reduce the excess production of skin cells. It causes serious birth defects in unborn babies, so pregnancy must be avoided whilst taking it, and for two years after stopping it. Because of how toxic it is in pregnancy, it's often avoided entirely in women of childbearing age.
- Apremilast (Otezla). This comes as a tablet. There isn't much information on how safe it is in pregnancy, so women are usually advised to avoid becoming pregnant whilst taking it.
- Biologics - for example, adalimumab, etanercept, infliximab. Most of these are specially-created antibodies that reduce the activity of a certain part of the immune system. They are usually given by injection or an infusion. They are often used if other systemic treatments haven't worked. Some of them have reassuring data to suggest they may be suitable to be used in pregnancy - but the risks and benefits always need to be carefully considered. Speak to your specialist for more information.
Can psoriasis go away without treatment?
One type of psoriasis - guttate psoriasis - does tend to clear up over a few months even without any treatment, although around one in three people later develop plaque psoriasis.
Otherwise, psoriasis is usually a long-lasting (chronic) disease. It tends to flare-up for periods and then get better between flares. Flares can improve on their own without treatment, and some people can have long periods without any active psoriasis. However, it's unlikely for psoriasis to go away completely without treatment.
Treatment can help to get psoriasis into remission - meaning it's no longer active. Psoriasis, as a long-term condition, can't be completely cured. Treatment is therefore required long-term, and may need to be repeated again and again when psoriasis flares. However, good treatment can get psoriasis under control, and minimise the impacts it has on life.
Other treatments for psoriasis
Other things that people with psoriasis might try include:
- Skin covers, or occlusion therapy. This involves putting a topical treatment on the skin, and covering it with something else, such as clingfilm, a waterproof dressing, or cotton socks or gloves. This enhances the effect of the topical treatment by causing more of the medication to penetrate into the skin. It might be used with steroid creams, for example, for small areas of psoriasis that are otherwise difficult to treat. Check with your doctor before trying this, as it's not suitable for all topical treatments.
- Skin camouflage creams. These can be used to cover-up areas of psoriasis, to make them less noticeable. They don't actually treat the psoriasis - the other treatments mentioned before do, though - but some people find them useful to cover areas of psoriasis, particularly if they're visible and distressing.
- Mental health support. Psoriasis can impact on people's mental health. Depression, for example, is more common in people with psoriasis. Support groups for people with psoriasis can be helpful, as can therapy and medication in some cases. Speak to a healthcare professional if your mental health is suffering due to psoriasis - or anything else.
- Treatments for psoriatic arthritis. Around one in three people with psoriasis get psoriatic arthritis - a condition that affects the joints. See psoriatic arthritis for more information.
- Treatments for nail psoriasis. Nail psoriasis can be difficult to treat. Treatments for nail psoriasis include:
- Keeping nails short.
- Using nail varnish to hide nail pitting.
- Topical treatments, such as strong topical steroids - sometimes in combination with a vitamin D analogue. However, topical treatments often don't get into the nail well enough to treat it.
- Steroid injections into the nail bed.
- Systemic treatments. However, these don't always work for nail psoriasis, and the side-effects and risks mean that they are usually only offered if there is also severe psoriasis elsewhere that hasn't responded to other treatments.
- Treatments to reduce the risk of heart disease. People with psoriasis have a higher risk of developing heart disease. The reasons for this are complex, and not fully understood, but might involve problems due to inflammation from psoriasis, and links between having psoriasis and other things that affect heart disease risk, such as smoking, drinking excessive alcohol, stress, depression, and obesity and overweight. Doing heart-healthy things - such as eating healthily, exercising, maintaining a healthy weight, avoiding or stopping smoking, and avoiding excessive alcohol - are important for everyone, but even more so for people with psoriasis. Other treatments, like statins, might be recommended for people at higher risk of heart disease.
Complications of psoriasis
People with psoriasis are more likely to develop other conditions, such as:
- Psoriatic arthritis, which causes pain, stiffness, and swelling of joints. See the psoriatic arthritis leaflet for more information.
- Anxiety and depression.
- Type 2 diabetes.
- High cholesterol.
- Fatty liver.
- Eye problems, such as dry eyes, blepharitis, and uveitis.
- Heart disease.
- Lymphoma, a type of blood cancer. However, the risk of this developing is still low overall in people with psoriasis.