Psoriasis

What is psoriasis and what causes it?

Psoriasis is a common skin condition.  We constantly produce new skin but with psoriasis the skin cells are made more quickly (up to ten times more quickly) and immature skin cells are pushed up to the surface.  The turnover of new skin cells is usually 28 days but with psoriasis it may only be two or three days.  The build-up of the skin appears as red patches on the surface of the skin covered by a silvery or white scale.

Approximately two percent of the population in the UK have psoriasis.  The cause of psoriasis is unknown but we do know that the tendency to develop psoriasis runs in some families. Psoriasis is NOT contagious and therefore cannot be caught from someone else with psoriasis. If you do have the tendency to develop psoriasis certain things can trigger it:

• Infection such as a sore throat.
• Damage to the skin such as a burn or scratch.
• Stress.
• Hormonal changes such as those that occur at puberty

Psoriasis is a chronic condition, which means for some children/teenagers it may reoccur throughout their life so it is important to understand the condition, and the treatments, which are used.

How is psoriasis treated?

Psoriasis is treated in various ways to try and control the symptoms such as itch, dryness and scale. The aim of the treatment is to minimise the impact of the condition on your life.

Moisterisers (Emollients)

There are lots of different types of moisterisers; there are creams, gels and ointments. In dermatology, we prefer ointments because they are thick and greasy and last longer on the skin. Creams contain preservatives which can cause stinging and irritation especially if the child has very dry skin. They also need to be applied more often than an ointment. Gels fall somewhere in between and tend to be favored by people as they are not as greasy as an ointment and last longer on the skin than a cream.

How much emollient is enough?

A thin shiny layer to the skin should be sufficient to all the affected areas. If treating the whole body approximately 600g per week for an adult and 250-500g per week for a child.

Top tips for emollients

1. As a moisturiser

Smooth onto the skin immediately after bathing and apply as often as needed to prevent the skin becoming dry.

Ideally it should be applied 2-4 times per day.

2. As a cleanser

Apply liberally to the skin and wipe off with single layer of paper tissue, taking care not to damage fragile skin.

3. As a soap substitute

Mix emollient with water in palm to form lather. Apply to the skin in a downwards direction. Gently rinse lather off skin leaving a thin layer of the ointment on the skin. Pat dry.

4. In the bath

Ointments can be dissolved in water. Add a spoon full of ointment to a small amount of boiling water in a jug. Then add to the bath water. Take care of the temperature of the water and when getting out of the bath, as it will be slippy.

How should emollients be applied?

Step 1  

Always wash your hands for 20 seconds before applying an emollient.  

Step 2  

Do not put your fingers into the tub as this can introduce bacteria and cause infection. Use a clean spoon or a spatula to take your emollient out of the tub.  If your emollient is in a pump this can be done straight on to your clean hands.

Step 3  

Apply to the skin in a downwards motion following the hair growth.   Do not rub in as this can block the follicles and cause infection.

What are topical corticosteroids?

Topical corticosteroids are a form of medicine applied directly to the skin which helps reduce inflammation, redness and irritation. The type of steroid is similar to those produced naturally in the body. Topical corticosteroids come in many preparations: ointments, creams, lotions and tapes.  Ointments (rather than creams) are generally best for dry skin conditions however is if the skin is wet and weepy a cream is usually preferred.

What are the different strengths of topical steroids?

Your doctor or specialist nurse will identify the correct strength of steroid for you to use on different parts of the body. They will also discuss how to increase or decrease treatment appropriately using the steroid ladder.

Worsening redness, scratch marks, thickness

1. Hydrocortisone 1% (mild)
2. Betnovate RD/ Eumovate (moderate)
3. Betnovate (potent)
4. Dermovate (very potent)

Topical corticosteroids are used on adults, children and young people. More potent steroids are typically in adults used on the body and mild/moderate steroids on the face and skin folds (under arms, breast folds, groin and genitals).

Children and young people will be guided by their doctor or specialist nurse with the use of mild and moderate steroids however when required potent steroids will be used when treating severe skin conditions.

How should topical corticosteroids be applied?

Step 1  

Always wash your hands for 20 seconds before applying a topical corticosteroid.  

Step 2  

Squeeze the topical steroid in a line from the last finger crease to the fingertip. This is a fingertip unit (FTU).   One FTU would be sufficient to treat an area equivalent to two adult handprints.

Step 3  

Apply to the affected area in a downwards motion following the hair growth.   Do not rub in as this can block the follicles and cause infection.

Step 4

Always wash your hands for 20 seconds after applying a topical corticosteroid.        

How much topical corticosteroid should be applied?

A thin shiny layer should cover the affected area. The fingertip unit method (FTU) gives a general estimate of how much should be used. One FTU would be sufficient to treat an area equivalent to two adult handprints. In children the fingertip and two handprints are based on that of an adult also. The tables below show how much is estimated to be used. This is based on the whole area being treated therefore if only a proportion of the area is affected the number of FTU should be adjusted accordingly.

Adults and young people

Children

Number of finger units (FTU)

How long should I use topical corticosteroids?

It is important that you follow the treatment plan given by your doctor or specialist nurse in order to avoid a flare of your skin condition. If used correctly topical corticosteroids should not cause side effects.  Thinning of the skin and stretch marks will occur only if a strong steroid is used incorrectly or over a prolonged time.

How does strong coal tar and tar pomade work?

Tar treatments work by loosening skin flakes, reducing inflammation and slowing the production of new skin cells; these are reproducing too quickly in psoriasis. Before starting treatment with coal tar or tar pomade, scaling should ideally be removed by adequate application of emollient.

Strong coal tar comes in three strengths, 1%, 2.5% and 5%.  The lowest strength is used first and if tolerated for a week the strength is increased and so on until 5% is used.  Sometimes tar pomade is prescribed instead and it comes in one strength only.  Whichever ointment is prescribed it should be applied one to two times a day to areas of psoriasis on the arms, legs, front and back, as directed by your doctor or specialist nurse.

Tar should not be used in the genital area or face (unless instructed by the dermatologist) as it may cause irritation.  

What are the side effects?

• One of the side effects may be irritation of the skin. If this occurs, reduce the strength you are using.  If irritation occurs when you are using the lowest strength of coal tar or using the tar pomade stop the treatment. If irritation persists despite stopping the treatment, contact your doctor or specialist nurse.  

• Tar products can be messy and smelly.  It may be useful to wear old clothes after application.  Sometimes we use special cotton bandages to stop the tar getting onto your clothes.

• Tar treatments also dry the skin so it is important to use an emollient in between times to keep your skin comfortable and moisturised.

• Tar treatments can make the skin more sensitive to sunlight so it is important to cover up with clothes, use a sunscreen and a hat if you are in the sun.

Precautions

• Topical corticosteroids, strong coal tar and tar pomade contain paraffin which is flammable. Do not smoke, use naked flames (e.g. candles, BBQs, be near people who are smoking or using naked flames) or be near anything else which may cause a fire whilst these products are in contact with your skin, clothes dressings or bandaged.

• If a topical corticosteroid causes irritation, please seek advice from your medical or nursing team.

• If you are using an emollient as part of your treatment plan also do not apply these at the same time as it may dilute your treatment and cause it not to work effectively. An emollient should be applied 30 minutes prior to applying a steroid or vice versa.

• If you are having ultraviolet light treatment or radiotherapy, check with your medical and nursing team if there is any specific guidance on your emollient use prior to starting treatment.

• Topical corticosteroids do not contain SPF and should not be used as sun protection. They should not be applied prior to sun exposure. Sun creams should be used when skin is exposed to direct sunlight with a medium/high UV level.

• Topical corticosteroids can worsen skin infections. If you have a bacterial, viral or fungal skin infection they should therefore be avoided, unless they are applied with an anti-infective agent or you are started on tablet medication to treat the infection. 

Useful sources of information

For Further Information

Medicines Information Patient Helpline:

Tel: 0191 282 3016. Available 9am to 4pm, Monday to Friday (excluding Bank Holidays). This helpline is available for patients of the Newcastle upon Tyne Hospitals, to answer any questions they may have regarding their medicines.

Dermatology:

Tel: 0191 282 0098. Available 9am to 4pm, Monday to Friday (excluding Bank Holidays).

Out-of-hours Advice:

Contact NHS 111 or visit your nearest NHS Walk-in Centre.