The term eczema describes a large range of skin diseases that cause itching and burning of the skin. It typically appears as red, swollen skin that is initially covered with small fluid-filled blisters that later break down to a scale or crust. The many different forms of eczema also have innumerable causes, both from within the body (e.g. stress) and outside (e.g. allergies, chemicals). The appearance of an eczema depends more on its position on the body, duration, severity and degree of scratching than the actual cause. The specific diagnosis of the type of eczema is therefore quite difficult.
Many substances have the ability to cause an allergic reaction in an individual. They are called allergens. Some people are far more sensitive to allergens than others. There are some strong chemicals to which nearly everyone will react, whereas other substances are relatively inert, and very few people react to them.
In most cases, the first exposure of a patient to a substance causes no reaction, but this initial contact commences the sensitization of the patient to that substance. Subsequent exposure, be it hours, days or years later, can then cause an allergic reaction, sometimes to a substance that has been handled without any problem in the past. Drugs are sometimes responsible for these reactions, particularly if present in creams. Chemicals, metals, elements, plants, preservatives, rubber, cement, etc., may all cause allergic eczema. A comprehensive list of all substances that can cause allergy reactions would double the size of this book.
The reaction to a substance is increased if the patient is hot and sweaty, as the substance is held on the skin in the sweat. Other situations that aggravate allergic eczema occur if the substance is caught in clothing, or is present at a point of skin flexion (e.g. in the groin, under breasts, armpit). The older the patient, the more severe the reaction. Allergic eczema is therefore relatively uncommon in the young, and very common in the elderly.
The sites of the eczema rash on the body correspond to the points where the allergen has been present on the skin. This may give a clue to the nature of the substance, but it is often very difficult to identify.
Once certain substances are suspected, the reaction to them can be confirmed by 'patch testing', where a patch of the substance is applied to the skin, and the reaction of the underlying skin is noted. If it is possible, the condition can be controlled by avoiding the substance, but pollens and dusts may be impossible to avoid.
Treatment involves the use of steroid creams to weeping areas, steroid ointments to dry and scaling areas. If the reaction is very severe, steroids may need to be given by tablet or injection. Most patients respond well to treatment for a particular attack, but the rash may recur on subsequent exposure to the allergen. Unavoidable exposure to an allergen can cause a persistent rash that is difficult to treat.
Atopic eczema occurs almost exclusively in children and young adults, and the vast majority are under five years of age. Up to a third of the population are potentially atopic, but only 5% of children will develop this skin disease.
Atopy is the tendency to develop a sudden, excessive sensitivity to a wide range of substances. It is a reaction similar to allergy, but not the same, as no previous exposure to the substance is required, and there must be a genetic predisposition to atopy present.
Atopic eczema may be triggered by changes in climate or diet, stress or fibers in clothing. In the majority of cases, the substance causing the atopic reaction cannot be identified. The rash occurs in areas where the skin folds in upon itself (e.g. groin, arm pits, inside elbows, neck and eyelids). It is more common in winter and urban areas (possibly due to pollutants such as vehicle exhausts), has a peak incidence between 6 and 12 months of age, and may cause lymph nodes in the neck, groin and armpit to become enlarged and tender.
The rash is extremely itchy, and invariably any blisters that form are rapidly destroyed by scratching. The scratching changes the normal appearance of the eczema, so that it appears as red, scaly, grazed skin that may be weeping because of a secondary bacterial infection that has entered the damaged skin. With time, and repeated irritation by scratching, the skin may become hard, thickened, and have the appearance of a large number of tiny pebbles under the skin.
Skin tests and blood tests can be performed to determine whether or not an individual has an atopic tendency, but as only 15% of these people will develop atopic eczema, they cannot prove that the rash is caused by this disease.
The high incidence in childhood, and the spontaneous settling of the rash with time, has led to a number of theories regarding atopy. It is possible that there is a hereditary lack of a specific type of immunoglobulin (immune system protein) or white blood cell in childhood that corrects itself as the child matures. This does not affect their health in any other way.
Treatment involves the use of moisturizing creams to soothe the inflamed and scratched skin, steroid creams to reduce the inflammation and itch, and soap substitutes to prevent drying of skin when bathing. Antibiotic creams may be required if there is an infection present. In severe cases, steroid tablets may be required to control the rash, and antihistamines to control the itch.
Steroid creams may be needed repeatedly over many months or years to keep the condition under control, but the vast majority grow out of the condition in later childhood or the early teen years. There is no specific cure, but effective control can be obtained in the majority of cases.
Discoid eczema (nummular eczema)
Discoid eczema effects mainly young adults, and both sexes. It appears as discs or 'coins' of scaling, red, thickened skin on the back of the forearms and elbows, back of the hands, front of the legs and the tops of the feet. The affected areas can vary in size from a few millimeters to three centimeters or more. The cause is unknown. Diagnosis can be confirmed by a biopsy (cutting out a piece) of the edge of one affected skin patch. It is frequently confused with fungal infections.
Discoid eczema is treated with steroid creams, which cause rapid healing of the rash. Antihistamines are occasionally necessary for the itch. Unfortunately, there is a tendency for recurrences, and repeated treatments may be required for each attack. After a period of many months, or a couple of years, the attacks cease.
Irritant eczema (housewives dermatitis)
Irritant eczema is due to the skin being exposed to irritating substances such as caustics, acids, detergents, bleaches, oils, soaps, solvents, washing powders and a host of other chemicals. The hands are obviously the part of the body most likely to be exposed, and the majority of cases of irritant eczema occur on the hands. Because of the likelihood of detergents and soaps causing the problem, this condition has also been named housewives dermatitis. However, in babies, drooling saliva, and feces and urine in nappies may cause the eczema. It can occur at any age, in both sexes, and at any site on the body. The affected skin becomes dry, cracked, red, swollen and in severe cases, painful and ulcerated.
Treatment involves removal of the irritant substance if possible. Cotton-lined gloves should be used for household chores. Soap should be avoided, substituted with moisturizing creams. In the workplace, a change in work practices, or even a new job may be necessary to stop the eczema from recurring. Barrier creams and protective clothing can also be useful. Removal of the irritant results in a cure. Unfortunately, this is not always practical, and steroid creams can be prescribed in various strengths and forms to control acute attacks and prevent recurrences.
Photosensitive eczema This uncommon type of eczema affects the areas of skin that are exposed to light, usually in middle-aged and elderly men. The rash is red and covered with scales and is intensely itchy. The face, forearms and hands are the most common areas affected. It is caused by a reaction in the skin to ultraviolet wavelengths in sunlight. In rare cases, it can become so severe that the patient cannot go outside during the day. Fluorescent lights also give off ultraviolet radiation and can cause this reaction.
Treatment involves use of long-sleeved shirts, hats and UV sun screen creams to reduce exposure to sunlight, and very strong steroid creams to settle the rash. Occasionally steroid tablets are also required.
Once established, the condition persists for life. It may force some patients to reverse their lifestyle - sleeping during the day and being active at night - in order to avoid the sun.
Seborrhoeic eczema is a widespread, common eczema that can occur at any age. It results from inflammation of the sebaceous glands in the skin, which are responsible for producing the oil that lubricates and moistens the skin, but the basic cause of this inflammation is unknown.
In infants, Seborrhoeic eczema frequently affects the scalp to cause 'cradle cap' or the buttocks to cause 'nappy eczema'. Other frequently affected areas are the cheeks, neck, armpits, groin and folds behind the knees and elbows and under the breasts. In adults, it is responsible for some forms of dandruff. On the scalp, it appears as a red, scaly, greasy rash. In skin folds, the skin is red. moist and breaking down into tiny ulcers On exposed areas such as the face, the rash is red, scaling and may contain tiny blisters. There is often a secondary fungal infection present in seborrhoeic eczema, and this must be treated as well as the rash.
The scalp is treated with a lotion or cream to remove the oil and scale from the skin, and regular shampooing. Tar solutions can be applied in resistant cases In other areas, mild steroid lotions or creams are used. Soap substitutes should be used.
Seborrhoeic eczema tends to be chronic and recurrent. Children often grow out of it in the early teens, but in adults it may persist for years with good and bad periods that occur for no apparent reason
Varicose eczema (hypostatic eczema)
More women than men have varicose eczema, and it is far more common in the elderly. It affects the inside of the shin, just above the ankle, in patients with and without varicose veins, though it is more common if varicose veins are present. The skin is itchy, red, shiny, swollen, dry and covered with scales. It is easily injured by even slight bumps, and very slow to heal. Varicose eczema is caused by a poor return of blood through the veins from the feet to the heart. Blood pools in the feet, and causes pressure on the skin, which reacts to give this type of eczema. Ulcers are a common complication, as are bacterial skin infections, and allergy reactions. These must be treated separately from the varicose eczema.
Treatment involves elevating the leg as much as possible, using support stockings or pressure bandages, and raising the foot of the bed slightly. If varicose veins are present, it may be appropriate to remove them surgically. Mild steroid creams and coal tar solutions are used on the eczema. The condition is usually chronic, and the results of treatment poor. Controlling the rash and preventing ulcers and other complications are the aims of treatment.
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