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| 1. Atopic Dermatitis (eczema) |
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Atopic dermatitis involves chronic, itching, superficial inflammation of the skin. This occurs in nearly 0.7% of population. About 90% of the cases appear between the 2nd month of life and age five. The evidence so far indicates that the tendency to develop eczema is inherited and involves more than one gene. Factors both inside and outside the body may be involved, but the exact cause of eczema is still uncertain. |
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Itching is the major symptom of eczema. Other symptoms include redness of the skin, swelling, and blisters. In its chronic state, the patient’s skin thickens, darkens, cracks and scales. Symptoms most often appear on the neck and face and in the bends of the knees and elbows. |
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In addition to its unpleasant symptoms, eczema carries a risk of additional complications and problems, including the development of other skin disorders. These patients have a high susceptibility to several types of skin infections. Also patients with severe eczema have an increase incidence of cataracts. |
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Eczema is associated with allergic diseases. Most patients also develop hay fever or asthma or have a family history of these diseases. Moreover, eczema patients usually have positive skin tests for allergens. Many children outgrow eczema. Some heal in infancy, and with most, improvement is common around puberty. However, children with a family history of eczema and those who develop asthma and hay fever are more likely to continue to have eczema as adults. |
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| 2. Allergic Contact Dermatitis |
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It is an allergic skin reaction to certain substances after touching them. These substances include include poison ivy, poison oak, drugs, antibiotics, cosmetics, certain metals such as nickel and chromates, and a number of environmental, industrial, and synthetic chemicals. |
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The symptoms of allergic contact dermatitis include a red rash, swelling and intense itching. Blisters may develop and break open, forming a crust. In severe cases, the rash and blisters may spread all over the body. |
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The disease may be acute or chronic. Symptoms may appear 7 to 10 days after the first exposure to an allergen. More often, it may require many repeated low-level exposures to trigger an allergic reaction. Once the sensitivity does develop, contact with the triggering allergen will produce symptoms within 24 to 48 hours. An attack builds in severity from 1 to 7 days. Even without treatment, healing often occurs in 1 or 2 weeks, although it may take a month or longer. Sometimes job changes may be necessary to avoid such allergens. |
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| 3. Urticaria (commonly called Hives or Nettle Rash) / Angioedema |
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Hives is characterized by red, swollen, intensely itchy blotches on the surface of the skin. If the swelling occurs in the deeper layers of the skin, or in the tissue below the skin, it is called angioedema. Angioedema most often occurs on the hands, feet, and face. These swellings arise suddenly, rarely persist longer than a day or two, and may recur indefinitely. |
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In chronic cases, a vase majority (more than 70%) are of unknown causes. For acute cases, the majority of urticaria reactions are non-allergic (with no involvement of the immune system) and are due to irritant chemicals, such as: |
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Preservatives (e.g. benzoic acid, sorbic acid, cinnamic acid) |
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Fragrances |
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Medications applied to the skin |
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Animal products, and plant products (including nettles and seaweed) |
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Foods coloured by tartrazine, a yellow food dye (yellow #5) |
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Hives sometimes follow the use of aspirin |
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Natural rubber latex (also called latex allergy) - it occurs mainly in well-defined groups, such as healthcare and rubber-industry workers, and people with bladder problems requiring permanent catheterization. |
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| 4. Vesiculobullous diseases (blistering) |
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There are three uncommon but debilitating vesiculobullous diseases, all with blisters developed on the skin: |
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Pemphigus Vulgaris |
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Thin, flaccid blisters develop on normal appearing skin. The disease usually begins in the mouth, and involves the mucous membranes. Ruptured blisters heal slowly, if at all. The exact mechanisms causing this disease are unknown. |
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B. |
Bulous Pemphigoid |
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Firm blisters with reddened bases form, mostly on the neck, groin, and armpits. Isolated blisters may occur on only one part of the body, especially the lower legs. This disorder occurs mostly in the middle-aged and elderly. |
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C. |
Dermatitis Herpetiformis |
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Firm blisters with reddened bases form in small groups, most often on the buttocks, lower back, shoulders, elbows and knees. These cause intense itching. A significant number of patients suffer bowel disorders, but the relationship between the gut and the skin diseases is unknown. |
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| 5. Vasculitis (inflamed blood vessels) |
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Vasculitis involves chronic inflammation of the blood vessels. Small, solid elevations, dusky red to purplish, appear on the skin and do not blanch when pressed. Less common symptoms include hives (mostly in women), nodules, blisters, ulcers, tissue death, and a mottling of the skin. |
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The disease produces itching or burning, and occasionally pain. Patients may also suffer fever or malaise. Symptoms may recur over weeks or years, leaving a temporary darkening of the skin or even scars. The disorder can cause ulceration and prolonged disability. This disorder may reflect a serious systemic disease. Infections or drugs may cause the disease in some cases but many other cases develop for unknown reasons. |
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