Home   >   Ask the Expert   >   The itch that rashes

The itch that rashes

By on August 31, 2009

Atopic dermatitis (eczema) was so described by a French dermatologist, Leonard Jacquet, over 100 years ago.  It was thought the skin-changes in this common, childhood condition resulted from scratching.  The word atopy (from the Greek atopos, meaning ‘out of place’) implies there is a reaction to something in the environment. But is this true, and if so, to what?  Unfortunately, we don’t know for sure.   

There is often a personal or family history of eczema and over half of the sufferers have asthma or hay-fever as well.  The number of people with eczema has increased in the last few decades, and this may be due to greater exposure to atmospheric pollution or to house-dust mites.  A majority of patients have positive skin-prick tests for house dust or pollens, etc.; or positive blood tests for allergy but a significant minority do not. So such tests to try to find out what the patient is allergic to, though intuitively appealing, are not very helpful in practical terms.

Food allergies: These occur, but are not reliable indications that a particular food or group of foods, such as dairy products, eggs, fish, and nuts, are responsible for the skin condition.  Even if the food in question is avoided, it is unpredictable as to whether there will be a corresponding benefit.    

The main feature of the disorder is inflammation of the skin, which shows itself as an itchy rash.  It often affects the bends of the elbows and behind the knees, or the face, and sometimes is extensive.  There is usually an associated dryness of the skin.  Since the cause is unknown, there is no cure.  However, in most children, it improves naturally by two or three years and most have grown out of it by the early teens.  Sometimes it recurs in adolescence or early adulthood but most people have recovered by the age of 30.  

Much can be done to keep the problem under control.  Dryness of the skin can be treated by the frequent application of moisturisers.  It can be very helpful to use a soap substitute for washing, such as emulsfifying ointment (hydrophyllic ointment), since normal soap by design, removes the natural oil from the skin.   

The principle of treating the inflamed skin is to use an ‘anti-inflammatory’ cream or ointment, of which the most effective are called steroids (cortisone) preparations.  Many people, however, have a quite unjustified reluctance to use them, fearing they will ‘damage the skin’.  I would like to quote from a textbook of dermatology written by an eminent British specialist:  “The fear of side-effects from topical steroids has got quite out of hand… an almost pathological loathing for them has developed despite the fact that they represent the single most effective remedy for controlling the disease if used sensibly.”

Steroids should be used sparingly; that is, a thin smear should be applied to the eczema only, not to the surrounding skin, and gently rubbed in.  One daily application is probably sufficient.  They vary in strength, and while the strong ones may be needed for more resistant parts of the body, only weak steroids (such as 1% hydrocortisone) should be used on the face.  There are other medicines which do not contain steroids, such as Tacrolimus (which, interestingly, was isolated from a type of bacterium found in the soil in Tsukuba in Japan).  Although effective, it produces a burning sensation when first applied and it probably hasn’t been in use long enough for its place in the treatment of eczema to be established.  As with any chronic ailment, it is important to find a knowledgeable and interested physician to supervise treatment. 

 

About Dr. Gabriel Symonds

Dr. Gabriel Symonds was the director of the Tokyo British Clinic. The clinic closed down in May 2014 after serving the expatriate community for 20+ years. Dr. Symonds has retired and the Tokyo British Clinic is now closed. Dr Symonds will continue to live in Tokyo and may be contacted by e-mail over any questions concerning medical records or related matters: symonds@tokyobritishclinic.com He will be available from another address for: smoking cessation psychotherapy/counselling circumcision information Tel: (03) 5458-6099 www.tokyobritishclinic.com