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.
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 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.