Understanding Eczema

What is eczema?

What will I find in this book?

This short book is intended for those who want to know more about eczema, either because they have it themselves or because it affects a relative or friend for whom they are caring.

There are several different types of eczema. The most common of these is atopic eczema – the kind suffered mainly by babies and children. This book therefore covers atopic eczema in childhood in greater detail than other forms of eczema.

Other types of eczema trouble us at different times of life for a number of reasons. For some, it is work related, whereas others develop a specific allergy to something to which they are exposed at home and work. And, as we get older, our skin becomes drier and thinner, which contributes to certain forms of eczema in old age.

This book should help you understand some of the basic rules in eczema, how it arises, the principles of treatment and what kind of professional help is available.

What is eczema?

The term ‘eczema’ covers a wide range of skin problems, which trouble people at different stages in their lives. It crops up in many different ways, such as in an elderly person with dry red skin around the ankles, a child with weeping red areas on the wrists, or someone whose eyelids have become itchy, red, dry and puffy in reaction to make-up.

Common features of eczema include: itch, redness, dryness and wetness. These are described below.

Itch

Itch occurs with nearly all forms of eczema, varying from mild irritation to a hopelessly distracting and distressing symptom that makes life miserable for the sufferer and others involved.

Redness

Redness is usually present in eczema and this redness can fluctuate, appearing bright red at some times of the day while at others it is barely noticeable. The redness is usually most obvious when you are hot or have exercised, or after a hot bath.

Dryness

Eczema is usually dry, making your skin feel rough, scaly and sometimes thickened. Dryness reduces the protective quality of the skin, making it less effective at protecting against heat, cold, fluid loss and bacterial infection.

Wetness

In severe eczema, or after a prolonged period of scratching, the skin’s protective character can be reduced further. The skin becomes wet with colourless fluid. This is fluid that has oozed from the tissues, sometimes mixed with blood leaking from damaged capillaries (small blood vessels). Wetness usually occurs when eczema is at its most itchy and is very likely to become infected.

Some wetness may come from small vesicles (pin-head blisters), which burst when scratched. These are most commonly found on the hands and feet, along the edges of the digits or on the palms or soles.

What is the skin made of?

The skin is your largest organ, weighing about four kilograms and covering about two square metres. It is your interface with the environment, and it protects you against chemicals, bacteria and radiation, helping you to maintain a stable body temperature, and stopping you from losing fluid and vital body chemicals. Your skin contains nerve endings that allow you to feel touch, temperature and pain.

Nails, which are also part of your skin layer, are useful for prising things open, among other things. Skin is strong and resilient, yet also flexible. The skin is made of three layers: epidermis, dermis and fat. These are described below.

Epidermis

The outer layer is the epidermis, which contains sheets of epithelial cells called keratinocytes. These keratinocytes are produced at the junction between the epidermis and the second layer of skin, the dermis. The epidermis is supported from below by the dermis.

The epidermis contains many layers of closely packed cells. The cells nearest the skin’s surface are flat and filled with a tough substance called keratin. The epidermis contains no blood vessels – these are all in the dermis and deeper layers.

The epidermis is thick in some parts (one millimetre on the palms and soles) and thin in others (just 0.1 millimetre over the eyelids). Dead cells are shed from the surface of the epidermis as very fine scale, and are replaced by other cells that pass from the deepest (basal) layers to the surface layers over a period of about four weeks.

The dead cells on the surface take the form of flattened, overlapping plates, closely packed together. This layer is known as the stratum corneum and is remarkably flexible, more or less waterproof, and has a dry surface so that it is inhospitable to micro-organisms.

Dermis

The dermis is made up of connective tissue, which contains a mixture of cells that give strength and elasticity to the skin. This layer also contains blood vessels, hair follicles and roots, nerve endings, and sweat and lymph vessels and glands.

The elements of the dermis all carry messages or fluids to and from the epidermis. This is so that it can grow, respond to the outside world and react to what goes on inside the body.

Fat

Underneath the dermis is a layer of fat that acts as an important source of energy and water for the dermis. It also provides protection against physical injury and the cold.

What happens in eczema?

In eczema, the main problems occur in the epidermis where the keratinocytes become less tightly held together. Their barrier function is reduced.

Who gets eczema?

In part this may be an inherited tendency where patients with some forms of eczema have altered protein in their skin cells. This protein is called filaggrin.

Where it fails to work adequately, the skin is more vulnerable to irritant materials and liquids and materials that might provoke an allergic reaction. For others with eczema, the skin cells may have been damaged by rubbing or some other process.

How does that produce eczema?

In either instance, the skin becomes vulnerable to external factors such as soap, water and more aggressive solvents such as washing up liquid, or solvents used as part of work or hobbies. These solvents dissolve some of the grease and protein that contribute to the natural barrier of the skin.

Once this process has begun, the skin may become inflamed as a reaction to minor irritation such as rubbing or scratching. This, in turn, makes the eczema worse and a cycle of irritation, inflammation and deterioration of eczema becomes established.

As part of this cycle, the skin becomes less effective as a barrier. It is less effective at preventing damage from solvents and abrasive materials acting from the outside, and it is also more likely to lose body moisture from within.

In a small patch of eczema, this can mean just a few vesicles (very small bubbles in the skin) bursting and leaking water. As the eczema gets worse, the fluid may come from the dermis and include blood from broken capillaries.

When severe eczema covers a large percentage of the body surface, it is possible to lose substantial amounts of body fluid, blood and protein through the skin. In addition to these materials, the body can lose heat from the skin, which can become important in people who are physically infirm.

The barrier function of the skin is reduced further when scratching occurs and breaks are gouged in the skin by fingernails. As with solvents, this fuels the eczema and is termed the ‘itch–scratch cycle’.

When skin becomes broken and there is a mix of blood, fluid and protein on the surface, there is a high chance of infection. This infection is usually bacterial and will add to the symptoms and severity of the eczema.

Eczema and the immune system

The epidermis is the place where the outside world meets the body’s immune system. Usually the immune system reacts only to parts of the outside world that present a danger, such as insect bites.

In many people with eczema, however, the immune system reacts more vigorously than usual to a wider range of normally harmless influences such as animal dander (small particles of hair or feathers), pollen and house-dust mite. As these trigger allergic reactions, these substances are known as allergens.

The immune system tries to destroy allergens by releasing a mixture of its own irritant substances, such as histamine, into the skin. The result is that the allergen may be altered or removed, but at the expense of causing soreness and making the skin fragile so other problems can develop, such as bacterial infection or damage from scratching.

How common is eczema?

Eczema is one of the most common skin disorders. Studies by general practitioners suggest that around 30 per cent of all people with skin problems have eczema. Of those referred to hospital with skin problems, about 20 per cent have eczema in some form. Atopic eczema is the most common form, particularly in children, affecting 10–20 per cent to some extent.

What kind of eczema is it?

Eczema can be categorised according to the main sites or the age groups typically affected. Each category is described in greater depth later in the book.

Is it definitely eczema?

Several skin conditions are red and itchy like eczema and may look the same initially; some are described here. It is, however, important to seek medical advice about any persistent or worrying rash.

Urticaria

Also known as hives, this is a distressing itchy rash of red bumps with a surrounding pale ring. Urticaria can crop up all over the body. It tends to move around, settling in one area, then appearing elsewhere, usually over a period of about 24 hours. The rash can disappear completely for short periods; it may go away during the night and gradually reappear during the day.

Unlike eczema, the skin does not become particularly dry and will not ooze unless scratching is so severe that it breaks the surface. Urticaria usually settles within a few days – although sometimes it can go on for months.

Psoriasis

Psoriasis can look like eczema at several sites on the body, but is far less common in childhood. The rash appears more silvery and is less itchy. Unlike eczema, it can have a very clear edge, which is sometimes slightly raised.

Psoriasis is more likely to affect the front of the knees and back of the elbows. It is more common in the scalp and around the ears, and there may be changes in the nails with small dents (pits) and lifting up of the nails. Psoriasis may be confused with seborrhoeic eczema or gravitational eczema.

Rashes with fever

Blotchy red rashes are common during childhood. Some are connected with specific illnesses, such as German measles (rubella), or just with having a high fever. Sometimes, the rash has no obvious cause, and will pass within a day or two and cause no concern.

Meningococcal meningitis

The important rash not to miss is the rash of meningococcal meningitis. All the other rashes mentioned so far are red, but look paler if examined through the bottom of a glass, pressed against the skin.

In meningococcal meningitis, bleeding into the skin produces patches of purple discoloration which do not become pale when the glass is pressed against the skin. There is no blood on the surface, however, and no blood will come off on the glass. Also, the rash is not itchy. If you are worried that a rash may be the result of meningitis, seek urgent medical help.

Reactions to sunlight

Sunburn

The most obvious reaction to sunlight is sunburn, which appears within a few hours of exposure to intense sunshine. In babies and small children, quite mild sunshine can produce sunburn.

The connection with bright sunshine means that it is usually easy to distinguish sunburn from eczema. The speed of the reaction and the typical unpleasant tingling are also slightly different.

Polymorphic light reaction

This is usually seen in adolescents and young adults. It affects the backs of hands, forearms, top of the feet and the exposed part of the legs. The V of the neck is typically affected and, although the face is very exposed to sun, it may only be the nose, chin and top of cheeks that develop the rash.

It comes on quite quickly after sun exposure, usually quicker than sunburn, and is bumpy and red. There is a clear cut-off at the edge of clothing and straps, showing that sun is the cause.

The condition is worst in the first month or two of summer. The skin gets used to sunshine and the reaction usually disappears by mid-summer or autumn. Unlike sunburn, there is no blistering, scaling, soreness or tightness.

The redness may last for several days or longer. People who tan quite easily, even those with dark skin, may still get polymorphic light reaction.

Lupus erythematosus

This is a rare condition, in which there is a marked reaction to sunlight that can produce scaling, redness and sometimes itch. These three features mean that it could quite easily be confused with eczema. However, lupus gets worse in sunshine and, although there is some itch, it is seldom intense.

Infection

Scabies

Scabies is a common infestation with a small mite that lives in the upper surface of the skin. The mites are passed from person to person.

The scabies rash varies, but typically itches so much that people feel that they have never had anything like it before. There are often patches of eczema, and the tell-tale marks of small pustules and tracks around the wrists and in the finger webs. In children under 18 months of age, pustules are sometimes also seen on the soles of the feet.

Treatment of scabies

Treatment is available over the counter at your chemists. The pharmacist will discuss the products with you, and they all come with written instructions within the packaging as to how to use them.

However, diagnosis is sometimes difficult and, given the upheaval of treatment, you may want to confirm the diagnosis with your GP. This is particularly the case for children and babies, where treatment advice can be slightly different.

Impetigo

Impetigo is a bacterial skin infection that is most common in young children. Typically, a few patches appear first on the face. They are often itchy and may have blisters and yellow crusts.

Impetigo can spread quickly to other sites because scratching carries bacteria on the fingernails and breaks the skin surface, promoting infection. It also spreads between children. It is usually thought best to keep a child with impetigo home from school until the outbreak is fully under control.

Impetigo may develop as a complication of eczema. It can also develop in children who have no particular history of eczema, yet who develop patches of eczema beneath the infected crusts. This does not mean that they will go on to get eczema elsewhere, but probably means that they have a tendency to get irritant dermatitis.

Treatment of impetigo

For small areas of infection, treatment can be with an antibiotic ointment. Several are available on prescription. Those bought over the counter from the chemist are seldom sufficient. The ointment is best applied to the infected skin after the crusts have been removed.

This can be combined with the use of an antiseptic washing agent or simply with soap and water. When infection is beyond one or two small patches, it may be necessary to take antibiotics by mouth.

Routine precautions in a family would be for children not to sleep in the same bed and for an infected child to have a separate washcloth and towel. It may help prevent infection of school friends if children are kept at home until the crusts have settled and treatment is well established.

Impetigo usually settles within 7 to 10 days of effective treatment. There may be residual pink marks on the skin for several weeks after, but they eventually fade.

If infections are recurrent, it is sometimes helpful to take swabs from family members and from the nose of the infected person, to see if there is a source of bacteria that accounts for the repeated infection. This is done by the GP or practice nurse.

Fungal infection

Fungal infection, such as ringworm, can easily be confused with eczema on any part of the skin. It may resemble gravitational eczema or seborrhoeic eczema.

Fungal infection is particularly common on the feet, where it usually causes irritation between the toes (athlete’s foot). Sometimes it may be helpful to take a skin scraping to rule out fungal skin infection before proceeding with eczema treatments.

Skin scrapings are best done by someone with specific training in this technique. It might be your GP or practice nurse.

KEY POINTS

• The epidermis is the top layer of the skin and where most damage is seen in eczema

• Solvents such as excess water and soap are damaging to the epidermis

• Scratching and rubbing contribute to the ‘itch–scratch cycle’, making eczema worse

• When eczema oozes and leaves crust on the skin, it is often associated with bacterial infection

• Rashes that come on suddenly may be infection, or a reaction to infection

• If a new rash affects several household members at the same time, it is more likely to be infection than eczema and all household members may need treatment depending on the diagnosis

• Psoriasis can look like eczema but is rare in children and often has a silvery scale; it is more likely than eczema to affect the scalp