Eczema is a chronic atopic condition caused by defects in the normal continuity of the skin barrier, leading to inflammation in the skin. There is a genetic component to eczema and it tends to run in families, however there is no single inheritance pattern. It has significant variation in the severity of the condition. Some patients can have very occasional mild patches that respond well to emollients, where others have large areas of skin that are severely affected and require strong topical steroids or systemic treatments.
Eczema usually presents in infancy with dry, red, itchy and sore patches of skin over the flexor surfaces (the inside of elbows and knees) and on the face and neck. Patients with eczema experience periods where the condition is well controlled and periods where the eczema is more problematic, known as flares.
Pathophysiology
The simplified pathophysiology is that eczema is caused by defects in the barrier that the skin provides. Tiny gaps in the skin barrier provide an entrance for irritants, microbes and allergens that create an immune response, resulting in inflammation and the associated symptoms.
Management
Management can be thought of as maintenance and management of flares, similar to the management of chronic and acute asthma.
The key to maintenance is to create an artificial barrier over the skin to compensate for the defective skin barrier. This is done using emollients that are as thick and greasy as tolerated, used as often as possible, particularly after washing and before bed. Patients should avoid activities that break down the skin barrier, such as bathing in hot water, scratching or scrubbing their skin and using soaps and body washes that remove the natural oils in the skin. Emollients or specifically designed soap substitutes can be used instead of soap and body washes when showering or washing hands.
Some patients find certain environmental factors play a role in making their eczema symptoms worse or better. For example, it may completely resolve on holiday in warm, humid countries, only to flare on returning to the cold air in the UK. Environmental triggers, such as changes in temperature, certain dietary products, washing powders, cleaning products and emotional events or stresses can also play a role.
Flares can be treated with thicker emollients, topical steroids, “wet wraps” (covering affected areas in a thick emollient and applying a wrap to keep moisture locked in overnight) and treating any complications such as bacterial or viral infections. Very rarely IV antibiotics or oral steroids might be required in very severe flares.
Other specialist treatments in severe eczema include zinc impregnated bandages, topical tacrolimus, phototherapy and systemic immunosuppressants, such as oral corticosteroids, methotrexate and azathioprine.
Emollients
Depending on the severity of the eczema, some patients may only require thin emollients to maintain their skin barrier, whilst others with more severe eczema require very thick greasy emollients. The general rule is to use emollients that are as thick as tolerated and required to maintain the eczema.
Thin creams:
- E45
- Diprobase cream
- Oilatum cream
- Aveeno cream
- Cetraben cream
- Epaderm cream
Thick, greasy emollients:
- 50:50 ointment (50% liquid paraffin)
- Hydromol ointment
- Diprobase ointment
- Cetraben ointment
- Epaderm ointment
Topical Steroids
The general rule is to use the weakest steroid for the shortest period required to get the skin under control. Steroids are very good for settling down the immune activity in the skin and reducing inflammation, but they do come with side effects. They can lead to thinning of the skin, which in turn make the skin more prone to flares, bruising, tearing, stretch marks and enlarged blood vessels under the surface of the skin called telangiectasia. Depending on the location and strength of the steroid there may be some systemic absorption of the steroid. The risks of using steroids need to be balanced against the risk of poorly controlled eczema.
The thicker the skin, the stronger the steroid required. Only weak steroids used very cautiously should be applied to areas of thin skin such as the face, around the eyes and in the genital region. It is best to completely avoid steroids in these areas in children.
The steroid ladder from weakest to most potent:
- Mild: Hydrocortisone 0.5%, 1% and 2.5%
- Moderate: Eumovate (clobetasone butyrate 0.05%)
- Potent: Betnovate (betamethasone 0.1%)
- Very potent: Dermovate (clobetasol propionate 0.05%)
Bacterial Infection
Opportunistic bacterial infection of the skin is common in eczema. The breakdown in the skin’s protective barrier allows an entry point for infective organisms. The most common organism is staphylococcus aureus. Treatment is with oral antibiotics, particularly flucloxacillin. More severe cases may require admission and intravenous antibiotics.
Eczema Herpeticum
Eczema herpeticum is a viral skin infection in patients with eczema caused by the herpes simplex virus (HSV) or varicella zoster virus (VZV). Patients can be very unwell. See the next section for more information.
Last updated January 2020