Forward
Allergic diseases are increasing at an alarming rate world-wide as well as in South Africa. Allergic rhinitis and atopic eczema have been noted to increase exponentially in recently reported studies. It is therefore imperative that patients are adequately informed about allergic diseases and methods available to treat them.
Skin allergies are a common problem and often very difficult to treat. They cause a tremendous amount of physical discomfort, emotional and psychological trauma and are very disruptive to patient’s lives. Their quality of life is adversely affected and this has many social and economic implications. Patients often have many misconceptions about skin allergies. This book is an attempt to address some of the common misconceptions about skin allergies. This book is an attempt to address some of the common misconceptions that I have experienced when treating patients with skin allergies.
The healthy human immune system protects the body from attack by foreign elements such as viruses and bacteria. Sometimes the immune system over-reacts and responds inappropriately to a harmless foreign element and an allergic reaction occurs. The allergic reaction manifests itself in different ways. For example, most people don’t react to pollen in the atmosphere and yet, there are some people who, when exposed to pollen, begin sneezing, itching and even wheezing. This indicates that the person is probably allergic to the pollen – they have an allergy. The foreign element causing the reaction is referred to as the allergen – in the case of pollen, pollen is the allergen. There are three common allergic diseases. They are asthma, allergic rhinitis and atopic eczema.
Where does an allergy come from?
It is believed that people inherit an allergy, or allergies, from their parents or grandparents – it is hereditary. If both parents have had allergies there is a greater risk of their children having allergies. And, if both parents have had the same allergic disease, the risk of the children becoming allergic in this area is as high at 70%.
The progression of allergic disease is referred to as the “allergic march” – i.e. the allergy’s movement from birth to adulthood. A baby may present with a food allergy or atopic eczema, which often subsides, but as he or she gets older so an allergy to inhaled particles in the air could develop. This often further develops into asthma or allergic rhinitis. Many allergies, occurring in both childhood and adulthood, affect the skin – and it is some of these skin conditions with which we are concerned and will examine further.
Let us take a brief look at the skin. The skin is an organ – the body’s largest and most visible. It is the outermost layer of the body – acting as protection against infection and solar radiation, whilst regulating body heat and synthesising Vitamin D. The skin is also a sensory organ sensitive to touch, temperature, pain, pressure and itching.
The skin consists of three basic layers: the epidermis – the thin outer layer consisting of dead, flattened horny cells that constantly regenerate. This is the layer of the skin that is usually affected by eczema.
The dermis – the thicker inner layer composed of connective tissue interspersed with hair follicles, sweat glands and sebaceous glands (the oil producing glands). This layer also contains blood vessels, lymph vessels and nerves. Urticaria usually affects the dermis.
Beneath the dermis is subcutaneous tissue – the inner-most layer of the skin containing primarily fat. Angioedema affects this part of the skin.
There are a number of allergens that affect the skin and bring about an allergic reaction – some worse than others. Here we will discuss some of the more common conditions, their diagnosis and treatment.
1. Allergic Contact Dermatitis (ACD)
When an external substance or allergen comes into contact with the skin, inflammation occurs – this is known as allergic contact dermatitis. The external substance could be quite harmless to non-allergic skins. The cause of allergic contact dermatitis is very different from the cause of the condition where acid or something as toxic touches the skin – that is irritant contact dermatitis.
Allergic contact dermatitis manifests itself as small blisters on the surface of the skin, which then rupture, followed by weeping and crusting. It is red and itchy, and ends up scaling and cracking.
Diagnosing Allergic Contact Dermatitis
The site of the reaction on the skin often gives a clue as to the offending or allergic substance. The test used to diagnose the type of allergen is called a patch test. This an adhesive strip, containing a number of the most common allergens, which is applied to the skin and then left. After a while, if there is an allergic reaction, the usual symptoms will occur – positively identifying the allergen.
Possible allergens in Allergic Contact Dermatitis
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Scalp – |
Hair dyes, lotions, topical medicines. |
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Face – |
Cosmetics, topical medicines. |
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Lips – |
Lipstick, toothpaste. |
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Hands – |
Jewellery, rubber gloves, metals, medicines. |
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Ears – |
Earrings (nickel), earplugs. |
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Body – |
Deodorant, clothes, dyes, elastic in clothing, medicines. |
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Genital area – |
Contraceptive creams or jellies, nappies. |
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Feet – |
Shoes, leather, powders, medicines. |
Treating Allergic Contact Dermatitis
Avoiding contact with the offending substance is the most obvious, although topical steroids are often used. In severe reactions oral steroids may be used, and antihistamines will be prescribed to relieve the itching.
Atopic eczema is a hereditary skin disorder resulting in a dry, very itchy, scaly red rash. The resultant scratching causes thickening of the skin, which often peels, becomes infected, weepy and appears to be pimply. It affects the face and neck in young children and the arms and legs in older children.
The causes of eczema
The causes of eczema vary and are unpredictable. A strong family history of allergic disorders such as asthma, eczema and allergic rhinitis usually exists. Food and inhalants are the primary allergens behind eczema, however, emotional disturbances, climatic and environmental factors have been found to dramatically influence the course of the condition.
Eczema can be very unpredictable and often resolves itself or flares up in response to many non-specific influences.
Eczema cannot be cured – only controlled, and then with some difficulty. Children with this condition are usually extremely uncomfortable and may become aggressive. A sympathetic attitude should be adopted in treating eczema.
a. General measures in the treatment of eczema
Identify Trigger Factors
| Identify and avoid the factors that cause flaring up of the condition. Keep a food diary – i.e. make a note of the foods ingested at the time when the condition worsens. |  |
Common foods causing eczema are: cows milk, eggs, wheat, fish, soya protein and citrus fruit – but one or a few may trigger a reaction – not all. A blood test (RAST) may identify causative foods. |
Moisturise the Skin
Eczema causes dry skin, so it is important to apply a moisturiser – frequently and regularly. Luke warm water rather than hot water should be used to bath in, and natural soaps such as Dove or Pears used. If the skin reacts to these soaps then aqueous cream is preferred. Pat the skin dry after bathing and apply a moisturiser immediately.
Avoid Itching
Use an antihistamine to avoid itching – particularly at night. Keep fingernails short.
(See list of antihistamines at the end of the book).
Clothes
Don’t overdress children and avoid woollen or synthetic clothing. Cotton is preferred. Avoid enzyme washing powders.
b. Treating eczema with steroid creams and ointments
These are the most effective form of treatment for eczema sufferers. They provide rapid relief and help to reduce the itch, redness and inflammation of the skin. Many different steroid creams of different strengths are available. In general the potent steroids should be used for short periods. Milder steroid creams can then be used to maintain control. They avoid flaring up of eczema. Only mild steroid preparations should be used on the face. Steroid cream can lead to thinning of the skin and should not be used for very long periods of time. Because the eczema sufferer’s skin is sensitive a reaction to topical creams and ointments may occur – these should then be avoided.
Topical steroids available in South Africa
LOWEST POTENCY
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Trade Name |
Pharmacological name |
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Cutaderm |
0.5% hydrocortisone |
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Dilucort |
0.5% hydrocortisone |
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Skincalme |
0.5% hydrocortisone |
LOW POTENCY
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Procutan |
0.1% hydrocortisone |
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Dilucort |
0.1% hydrocortisone |
MODERATE POTENCY
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Eumovate |
Clobestone butyrate 0.05% |
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Elocon |
Mometasone furoate |
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Cutivate |
Fluticasone propionate |
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Advantan |
Methylprednisolone acoponate 1% |
POTENT
|
Betnovate |
Betamethasone valerate !% |
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Synalar |
Fluocinolone acetonide 0.25% |
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Nerisone |
Diflucortolone valerate 0.01% |
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Locoid |
Triamicinalone acetonide 1% |
VERY POTENT
|
Dermovate |
Cobetasol propionate 0.05% |
|
Diprosone(Diprolene) |
Betamethasone diproprionate 0.05% |
c. Treatment of eczema
Infection
If the condition suddenly flares up or is very weepy or pustular, it may have become infected. A doctor must be consulted and antibiotics may be necessary.
Prevention eczema
There is strong evidence that exclusive breast feeding for the first six months of life and controlled diet of the nursing mother, plus a delayed introduction of solids may delay or even prevent the onset of eczema born into families with a history of allergies. Avoiding cigarette smoke, mites, pets and foods commonly provoking allergy may help prevention.
Prevention of asthma
About 50% of children with atopic eczema develop asthma later in life. Recent research has shown that Zaditen used early in children with atopic eczema can prevent or delay the onset of asthma.
Prognosis
Generally atopic eczema improves with age. About 40% of children will be cleared eventually but, will probably have a dry skin in later life. Some eczema is more persistent and may continue.
3. Urticaria (Hives)
This is an extremely itchy skin condition often result in red, raised patches on the body. When deeper layers of the skin are involved swelling of the face, hands or feet may occur. This more involved reaction is referred to as angioedema – and most often occurs together with urticaria. The wheals caused by urticaria usually only last a few hours but often recur.
Urticaria can occur at any age. Acute urticaria, only lasting a short duration, usually affects children and young adults, whereas chronic urticaria, recurring for more than six weeks, is more common in adults.
What causes urticaria?
There are two types of urticaria – allergic and non-allergic, with some being chronic and others being acute. In most cases of chronic urticaria, even though extensive tests are undertaken, no cause may be found. This condition is called Chronic Idiopathic Urticaria. In acute urticaria the condition usually occurs suddenly and resolves spontaneously within hours or days – the cause being obvious as will be discussed further.
Allergic urticaria
This type of urticaria reacts to an allergen which could be related to food, preservatives, colourants, drugs, insect bites, animal dander, worms or a bacterial/viral infection. The foods commonly associated with causing urticaria are: food chemicals, sea-foods, egg whites, strawberries, dairy products, nuts, citrus fruits, tomatoes, soya beans and salicylate (aspirin).
Contact urticaria
This is an uncommon condition and is experienced upon direct contact with a substance that causes a reaction. It differs from Allergic Contact Dermatitis in that a reaction occurs within minutes and is completely resolved within 24 hours. It is characterised by redness and swelling of the skin. Treatment involves avoiding the offending substance.
Substances causing contact urticaria
Medicines such as penicillin and salicylic acid.
Foods such as dairy products, eggs, fruits, nuts, sea-foods and certain vegetables. Further offending substances could be: animal dander, fragrances, nettles, cactus, wool, preservatives, rubber, exotic woods or cosmetics.
Drugs and preservatives known to cause urticaria
Any drug has the potential to cause urticaria, but the common ones are: antibiotics, penicillin, drugs containing sulphur, anti-inflammatory drugs, contraceptive pills, insulin, vitamins, laxatives, cough and cold preparations, some headache tablets, and X-ray contrast material.
Preservatives and additives such as benzoic acid, citric acid, sulphites, tartrazine and monosodium glutamate, however, that a detailed history of food or medicine consumption be noted to accurately identify the offending allergy.
Papular urticaria
This condition is common, particularly in children. It is itchy with crops of papules appearing on the skin. It most often occurs in summer and is usually the result of a variety of insect bites.
Physical or non-allergic urticaria
Direct physical exposure or stimulation are responsible for this type of urticaria. These physical factors could be heat, cold water, stroking of or pressure on the skin. There are a number of forms of this type of urticaria:
1. Dermatographism
Stroking the skin will create a raised wheal on the surface. The condition is usually treated with antihistamines.
2. Cold urticaria
The skin becomes red, itchy and may swell when exposed to cold.
3. Solar urticaria
This is very rare – caused by exposure to sunlight. The skin becomes itchy, red and swollen. Avoidance of sunlight, protective clothing and barrier creams are necessary.
4. Cholinergic urticaria
This type of urticaria occurs after hot showers, sweating and anxiety. Small pointed lesions appear anywhere on the body. Treatment with an antihistamine is usually successful.
5. Pressure urticaria
Delayed pressure urticaria occurs when pressure is applied to the body. Hours later swelling will appear on the affected part of the body. Tight clothing, pressure on hands or feet may cause a reaction. Steroids are used to treat this condition.
Treatment of urticaria
Much of the possible treatment of urticaria has already been mentioned. It is important, however, to avoid trigger factors which cause the condition to flare up. The use of antihistamines and steroids has been found to be effective in may cases. If urticaria is uncontrollable a combination of antihistamines may
be used to provide symptomatic relief. Patients differ in their response to antihistamines and those who experience drowsiness usually only do so in the first few days of treatment. Thereafter, tolerance to the medication is most often developed within a week. Zaditen, an oral preparation, has been found to be useful in treating chronic urticaria.
Testing for allergies
Investigating the specific skin condition to distinguish the type of reaction, whether it is an allergy or not, and type of allergy, is very necessary in skin allergy. There a number of tests to determine the type of allergy and the nature of the causative allergen.
1. There is a Skin Test where a panel of allergens is placed on the forearm and, if there is a reaction, these then helps to record the type of allergy. It is particularly useful in the case of inhaled allergens.