Eczema

Eczema is a chronic inflammatory skin condition which causes areas of skin to become dry, hot, itchy, red and even cracked. It is sometimes called dermatitis or atopic eczema. Infants often suffer from eczema of the face, neck and trunk while older children are more commonly affected at the flexural and extensor surfaces of the arms and legs. 

Eczema is the most common inflammatory skin condition in the world. It affects 30% of children in Ireland but the majority grow out of it (85%) and few go on to have lifelong eczema. The onset of eczema is often before 1 year of age. It is thought that earlier and more effective management of eczema is important in helping children to 'grow out of' their eczema.

Eczema is not caused by allergies but it can be significantly exacerbated by co-existing allergies both in terms of its extent, its severity and the number of eczema flares. Research indicates that eczema is primarily a disease of the immune system. Chemical messangers called Cytokines have been implicated in playing a critical role to the disease. These cytokines, particularly IL-4 and IL-13 (Th2 pathway cytokines) and IL-22 cause barrier defects in the skin and trigger inflammation that results in the clinical features of eczema. It is known that inherited abnormalities in the skin barrier can play a role in some cases. Impairment of the skin barrier results in increased permeability and reduces the skins antimicrobial function.

Formal allergy testing in conjunction with expert interpretation by our doctors can determine if there is an allergy contributing to your childs eczema. If an allergic environmental trigger such as House Dust Mite is found then this can be treated. We often see very significant improvements in this cohort of eczema patients.

Further Information for parents

What Is Atopy?

Atopy refers to the tendency in a person towards having eczema, asthma and hay fever. It is characterised by an overactive IgE mediated immune response to environmental factors. The same factors or triggers have no effect on the skin or airways of a non-atopic person. 

Atopy is primarily genetically inherited which means that atopy runs in families. Despite this, some children from atopic families never develop eczema, asthma or hay fever. Furthermore, children with no family history of atopy can suffer from any of these atopic conditions.

What makes the skin drier in Eczema

Dry skin is a sign of reduced function of the skin as a barrier. Therefore, any external factors that make the skin even drier can make eczema more difficult to manage:

  • Low Humidity (e.g. air-conditioning)
  • Hot or cold weather conditions (see below)
  • Washing and bathing:
    • too frequently
    • very hot water
    • hard water and soaps (increased pH)
  • Chlorine in swimming pools

Options to maintain skin moisture:

  • Limit showers or baths to once per day and try to make them brief.
  • Use a non-soap cleanser (e.g. Cetaphil).
  • Moisturise daily and always after bathing (e.g. Hydromol)

Irritants and Eczema

Most eczema sufferers are aware that certain substances irritate their skin and may even trigger an eczema flare. Eczematous skin is far more vulnerable to irritants such as:

  • Coarse fibres in clothes (wool & synthetic)
  • Harsh clothing detergents
  • Soaps
  • Make-up, perfumes and creams
  • Dusty environments

Options to limit the impact of Irritants:

  • Clothes detergents:
    • use fragrance free and non-biological detergents
    • reduce the amount of detergent used if possible
    • ensure clothes are well rinsed after washing
  • If using soap to wash your hands, rinse off thoroughly.
  • Wear protective clothing and gloves when using detergents and cleaning chemicals.
  • Limit the use of skin products except those prescribed for eczema.

Allergens and Eczema

Both an individuals genotype and their environment contributes to their risk of developing eczema, its severity and the response to treatment. If an allergy is identified as contributing to exacerbations of eczema then removal of the allergen from the affected patient's environment can result in improvement of eczema. Immunotherapy desensitisation treatment to house dust mite or pollen allergies can also help improve eczema in people who suffer from these allergies.

People who have atopic dermatitis with elevated IgE levels are more likely to have food allergies or allergies to environmental factors such as grass pollen, cat dander and house dust mites. Current research indicates that skin barrier defects that occur in atopic dermatitis alter immune function and so can induce food allergy secondarily. Primary sensitisation is more likely to occur when new allergens are introduced through inflammed eczematous skin rather than the gastrointestinal tract. It is therefore important that parents avoid introducing new foods, especially nuts and shellfish, during any acute exacerbation of eczema in infancy.

Climate and Eczema

Environmental conditions can have a big impact on eczema.

  • The cold and damp conditions we experience in Ireland during winter may cause eczema to become more resistant to treatment. Dehumidifiers may be beneficial for asthma but low environmental humidity can further exacerbate dry skin.
  • During the summer months eczema often improves. This is caused by the departure of the colder weather and the increased exposure to UV light has benefical effects in moderation. Sunburn should always be avoided.
  • In a small number of eczema patients sunlight can make their eczema worse. This is called photosensitive eczema.
  • Moving to a new house or new area can have a beneficial or detrimental effect on eczema.
  • Most people with eczema will become itchier and have redder skin when they are hot. Keeping cool in hot environments using a fan or air conditioning, and having cool showers or baths will help.

Options to reduce the impact of a challenging climate

  • Use superfine natural fibre clothing and bedding to reduce sweating and keep the skin cool.
  • Keep the temperature even throughout the house.
  • Keeping cool in hot weather is important. Use a fan or even air conditioning if necessary. Having short cool showers will help.

Stress and Eczema

It is well known that physical, psychological and social stress can act as triggers for eczema flares.

  • Physical stress include any other medical illness e.g. viral infections such as the common cold
  • Psychological stress e.g. bereavement, work stress
  • Social stress e.g moving house, changing school, family conflict

Eczema itself may be the source of stress. It can cause significant discomfort which can lead to missing school or work. In addition, for some patients it can be a major cosmetic concern which leads to further stress.

Further Information for health professionals

The Immune System and Eczema

The adaptive immune response evolves to become more robust and more specific during the first six months of life. The two main types of T Helper lymphocytes, Th-1 and Th-2, generally operate in a state of equilibrium. It has been found in atopic dermatitis that an imbalance often exists with a far greater number of Th-2 cells and their associated cytokine messangers. In additon, many of these patient have high levels of Immunoglobulin E (IgE) antibodies and eosinophils. 

The Th2 associated cytokines potentiate an immune response which leads to impairment of the skin barrier function. This causes the skin to become more vulnerable to penetration by 

  • Irritants such as soap, detergent, dirt
  • Allergens such as house dust mite, pollen, animal dander and microbes

Langerhans cells are the specialised macrophages that reside in the epidermis. In atopic dermatitis, they become activated by irritants and allergens and signal dermal T cells to produce an even greater Th2 response. This further impairs skin barrier function which allows heavier bacterial and fungal colonisation of the skin. The skin becomes more vulnerable to infection and infections can become more difficult to control.

Eczema and The Microbiome

The impact of the microbiome on atopic dermatitis has come under increased scrutiny of late. Exacerbations of eczema are accompanied by Staphylococcus aureus proliferation in the affected skin and a reduction in cutaneous microbiome diversity with fewer cutibacteria and malassezia yeasts than are present on normal skin. This is important because it is thought that the microbiome contributes to inflammatory immune responses in the skin. Researchers report that emollients increases biodiversity in eczematous skin.

The functions of microbial components of the skin flora are of particular interest to researchers. Areas such as the elbows, knees and axilla have higher moisture and humidity levels and consequently attract different microbiomes. It is hypothesized that different organism profiles found in different areas of the body might be responsible for the characteristic distribution of atopic dermatitis. 

References:

1. Royal Childrens Hospital (RCH), Melbourne: Eczema

2. Health Service Executive (HSE), Ireland: Eczema

3. DermNet NZ: Atopic Dermatitis