This comes from the word ‘atopy’, which refers to a group of conditions in which the immune system reacts to allergens in the environment by producing raised levels of immunoglobulin type E (IgE), which in turn leads to the changes in the skin.

Seventyfive per cent of cases present before the age of 6 months, rising to 90% before the age of 5 years. It is thought to affect 3% of infants and persists for several years.

Of the children affected, 60–70% will have gone into remission (no longer suffer from eczema) by their early teenage years, although they remain vulnerable to recurrences and may always have problems with dry skin. The pattern of rash on the skin varies with age:

• In infancy, it often starts on the face with vesicles and weeping. Distribution elsewhere is non-specific, but it does tend to spare the napkin area.
• As the child ages, the distribution becomes more flexural around knees, elbows, wrists and ankles. The skin becomes increasingly thickened, dry and excoriated – often looking ‘leathery’ (lichenification).

This pattern continues into adulthood, with increasing lichenification and an increasing tendency to affect the trunk, face and hands.

Will I ever grow out of my atopic eczema?

I am now in my thirties! Unfortunately, most adults who have atopic eczema that has persisted from childhood tend to find that it continues into old age. It is therefore very important that you work hard on finding a treatment regime that allows you to manage it as easily as possible.

I am 45 and have never had any problems with my skin. I now have itchy, round, scaly patches on my arms and legs that my GP says are eczema. Is this right?

Yes, these could be, although your GP may also have considered other causes such as fungal infection and psoriasis. This pattern is called discoid eczema. The precise cause of this has yet to be identified, but chronic stress and local infection may play a part.

As you have found, the rash typically presents on the limbs in people in their forties and fifties, and it is more common in men. Unlike atopic eczema, it favours the extensor surfaces and appears as round ‘plaques’ rather than being more spread out. These plaques are usually 5 cm or less in diameter.

Looking closely at them, you should see some tiny little blisters and crusting where the fluid from the blisters has dried. The underlying skin will probably be thickened. Discoid eczema can be very stubborn and difficult to treat, so it may persist for many months.

My son has what looks like eczema but just round his mouth. What might have caused it?

This could be another form of irritant eczema. If it looks red and dry with cracks or fissures, it is probably ‘lip-licking’ eczema. It might also be linked to irritation from, or even allergy to, toothpaste.

Various patterns are seen, depending on the original site of contact. Your case is typical of nickel allergy, which can also be seen under jewellery and metal fastenings in clothing, such as the studs in jeans. Other patterns include fingertip eczema from garlic, and eczema on the face and neck from perfume.

An allergic cause should be suspected if the pattern of eczema is unusual – eyelids, around leg ulcers, hands or feet – if there is a known exposure to some of the common allergens, or if the type of work is ‘high risk’, for example hairdressing, nursing, gardening or floristry.

My gran has very itchy legs with not much to see other than dry skin with a sort of criss-cross pattern. She used to get eczema as a child but says it didn’t look like this.

She probably has asteatotic eczema, which occurs in older people who may have had eczema in the past or have, at least, a tendency to have dry skin. It is made worse by low humidity in centrally heated rooms and the removal of the natural oils from washing with soap.

Diuretics can increase the problem from dehydration, and hypothyroidism should be excluded. As with your gran, it presents on the legs, which itch and show a background of dry skin with a superficial network of fine red lines giving a ‘crazy paving’ appearance.

These fines lines are actually small cracks or fissures in the skin. Treatment with water tablets (diuretics), for blood pressure or heart problems, can make it worse, as can having a thyroid gland that is not working very well.

My doctor says that my varicose veins have caused eczema. Is he right?

Yes, it sounds as though you have venous eczema, also called varicose, stasis or gravitational eczema. It is linked to poor blood flow in the veins in the lower legs, sometimes after clots in the deep veins.

The eczema is chronic, and the legs can become stained a browny colour from blood pigments getting into the skin. You will have to be very careful not to scratch the skin as it will be very fragile and prone to ulceration. If this does happen, you will need dressings and bandages; these can sometimes, however, lead to extra problems of allergic contact eczema, so be careful and look after your skin.

I have suffered from eczema since I was a child. In my adult years it has changed, and my GP has told me it was something called ‘pomphlics’. What is this?

‘Pompholyx’ is a word used to describe a pattern of eczema affecting the hands and feet that typically shows blistering and is very itchy.

There are recurring outbreaks of tense, thick-walled vesicles or larger blisters on the palms, along the fingers and sometimes on the soles of the feet. Each outbreak can last a few weeks and recur at irregular intervals. It is more common in hot weather and can occur in three types:

• in association with atopic eczema
• linked to allergic contact eczema – people allergic to nickel may also develop it in response to low levels of nickel in food
• in isolation (the cause here being unknown).

Are some types of eczema more common at different ages?

The age of onset can be helpful in deciding what type(s) of eczema a person has. Eczema in an infant is most commonly atopic (although this may appear discoid in places and can be aggravated by irritants) or seborrhoeic.

In the child and teenager, atopic eczema is most common, but there will be some instances of contact allergy, for example to nickel. In adults of working age, irritant, contact allergic, seborrhoeic, discoid and atopic eczema are all common and can occur at many body sites; pompholyx and venous eczema are recognisable by their locations. The elderly are prone to asteatotic eczema, especially on the shins, in addition to the types experienced by younger adults.

Does it look the same in the acute and chronic stages?

Acute eczema will occur quite quickly – hours or a few days – sometimes in previously normal skin. Little blisters may appear and then break to give a weeping surface. The underlying skin will be red, perhaps swollen and often a little bumpy.

Most acute eczema is very itchy, but when the skin surface has broken down, this may be replaced by soreness. As days go by, crusting and then scaling may occur alongside the weeping or gradually replace it. ‘Chronic eczema’ is eczema that has been present for a long time – usually at least weeks.

The ongoing inflammation, rubbing and scratching all contribute to an increased thickness of the skin, which may develop a leathery appearance and show much more prominent skin surface markings.

In dark skin, there may be changes in the pigmentation – both an increase and a decrease are possible. This thickened skin is liable to split, producing painful fissures, especially over the joints.

I get very confused by all the different types of eczema that can affect the skin. You say that the final process in the skin is the same for all of them. Why can’t we just call it eczema and get on with treating it?

Despite the fact that, at microscopic level, the skin looks very similar in the different types of eczema, this is the end stage as the skin can only behave in so many different ways when disordered. The main reason for trying to label the different patterns accurately is that the cause, severity and outcome vary enormously between the different eczemas.

Whereas some of the treatments are similar for the different types, there are many that are more specific, so accurate diagnosis is essential. Treating eczema is also not just about creams: it must involve prevention, and this is much more possible in some types than in others.