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 commonly develop facial, neck, scalp and truncal eczema while older children develop flexural and extensor eczema.

Eczema is the most common inflammatory skin condition worldwide. It affects 30% of children in Ireland and often develops before 12 months of age. The majority grow out of it and few children have lifelong eczema (15%). It is well known that the earlier the eczema is managed the earlier the child may 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. Current theories identify that atopic dermatitis is primarily a disease of the immune system, with cytokines being critical components to the disease. These cytokines, particularly IL-4 and IL-13 (Th2 pathway cytokines) and IL-22 cause barrier defects and inflammation that result in the clinical features of eczema. There is also evidence that inherited abnormalities in the skin barrier can play a role. This barrier failure causes increased permeability of the skin and reduces its 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 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 asthma, eczema and hay fever. It is characterised by an overactive 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 an atopic family never develop asthma, eczema or hay fever.  In addition, children with no family history can suffer from it.

What makes the skin drier

Dry skin is a sign of the loss of barrier function. Factors that make the skin even drier may make eczema harder to control:

  • Winter weather
  • Frequent washing particularly with very hot water
  • Washing in hard water (which increases pH)
  • Soap (which also increases pH) and antiseptics
  • Low humidity
  • High ambient temperatures
  • Chlorine in swimming pools

A brief shower or bath once a day is enough if you have dry skin. Ensure to use a non-soap cleanser and to moisturise after bathing. Regular use of an emollient helps skin retain moisture and combat dryness.

The role played by Irritants

Most people with eczema will notice that certain things seem to irritate their skin with immediate stinging or itching and may also cause a flare of eczema (irritant contact dermatitis). These are not allergies.

  • Soap
  • Harsh clothing detergents
  • Coarse fibres (wool and synthetic) and seams in undergarments
  • Cosmetic and perfumes
  • Prescribed and over-the-counter treatment creams
  • Dusty environments

It is common sense to avoid substances that irritate.

  • Dilute washing powder: use a small amount in each load and make sure the clothes are well rinsed out in freshwater. Select non-fragranced laundry detergent.
  • If you use soap to wash your hands, rinse off thoroughly.
  • Wear gloves / covering clothing to protect against detergents, cleaning chemicals, solvents at work and at home.
  • Limit preparations applied to the skin to those specifically prescribed for eczema.

Climate

Climate undoubtedly plays a major role in the severity of eczema.

  • Cold, damp climates may cause eczema to become more resistant to treatment. Keeping the temperature even throughout the house is probably helpful. Dehumidifiers tend to be more beneficial for asthma than for eczema as low environmental h+umidity can dry out the skin further.
  • Moving to a new house or new area can have a beneficial or detrimental effect on eczema.
  • Most people find that their eczema is better in the summer months. This is partly due to the increased exposure to ultraviolet light, which (in moderation) can have a beneficial effect on eczema. Sunburn is never a good idea! A small percentage of eczema sufferers find that the sun makes their eczema worse and should protect from sun exposure as much as possible. This is called photosensitive 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.
  • Choose superfine natural fibre clothing and bed linen to reduce sweating and help keep skin cool. Avoid coarse wool underlays.

Stress

Adults and children are liable to experience an exacerbation in eczema secondary to physical, mental or social stress.
Stress can come in many forms. Any other illness including a mild common cold may cause a flare in eczema.
Social stress such as a move to a new area, change in school, family conflict etc. may also affect eczema.
Eczema may be the source of stress: it is uncomfortable and can be a major cosmetic concern. The cost of medications and time off work for the patient and caregiver can also be very stressful.

Further Information for health professionals

The Immune System

The immune system develops in the first six months of life. There is a generally an equilibrium of the two main types of T Helper lymphocytes (small white blood cells), Th-1 and Th-2. In atopic dermatitis, there is often an imbalance, with far more Th-2 cells and their associated chemical messengers (cytokines). In some children, there are also high levels of the antibody immunoglobulin E (IgE) antibodies and eosinophils (the white blood cells associated with allergy). 

The Th2 associated cytokines contribute to the loss of skin barrier function:  

  • Water is lost
  • Irritants may penetrate (soap, detergent, solvents, dirt etc.)
  • Allergens may penetrate it (pollens, dust-mite antigens, microbes).

The specialised immune cells of the epidermis (Langerhans cells) have an increased response to these antigens in atopic dermatitis and interact with dermal T cells to produce an even greater Th2 response further exacerbating the barrier defect.

  • Ceramide (a fatty acid) and Filaggrin are reduced
  • Bacteria colonise and infect the skin
  • Infections are more difficult to control

So both the genetic make-up of the individual and external environmental factors contribute to the likelihood of developing eczema, its severity and its response to treatment.

Allergens and Eczema

People who have atopic dermatitis associated with elevated IgE are likely to have allergies to food or environmental factors such as grass, cat dander and dust mites. If an allergy is present AND exposure to the allergen results in a persistent worsening of eczema, removal of the allergen from the affected patient's environment can result in improvement of eczema.

Current research indicates that skin barrier defects that occur in atopic dermatitis alter immune function and so can induce food allergy secondarily. It is therefore important that parents avoid introducing new foods such as nuts during an acute exacerbation of eczema in infancy.

The Microbiome

The functions of microbial components of the skin flora have only recently become of interest to atopic dermatitis researchers. It is postulated that different organisms in different body sites might account for the characteristic distribution of active lesions of atopic dermatitis — for example in the moist elbow and knee creases. 

The microbiome likely contributes to normal and abnormal inflammatory responses in the skin.  Flares of atopic dermatitis are accompanied by a proliferation of Staphylococcus aureus on lesional skin and a reduction in the biodiversity of the cutaneous microbiome (dysbiosis), with fewer malassezia yeasts and cutibacteria than are present on normal skin. Researchers report that emollients can increase biodiversity in eczema skin.

References:

1. Royal Childrens Hospital (RCH), Melbourne

2. Health Service Executive (HSE), Ireland

3. DermNet NZ: Resources for Medical Doctors