Disorders of the Skin - Allergies and itching

Itching and inflammation of the skin may be caused by an allergic reaction, by exposure to poisonous plants, or by a generalized infection.


Dermatitis is the term used for an inflammation of the skin. The term for allergic reactions of the skin resulting from surface contact with outside agents is contact dermatitis . This condition is characterized by a rash and may be brought out by sensitivity to cosmetics, plants, cleaning materials, metal, wool, and so on. Other forms of dermatitis can be caused by excesses of heat or cold, by friction, or by sensitivity to various medicines. Dermatitis is usually accompanied by itching at the site of the rash.

Poison Ivy

This common plant, unknown in Europe but widespread everywhere in the United States except in California and Nevada, produces an allergic reaction on the skin accompanied by a painful rash and blisters. Some people are so sensitive to it that they are affected by contact not only with the plant itself but with animal fur or clothing that might have picked up the resin weeks before.

A mild attack of poison ivy produces a rash and small, watery blisters that get progressively larger. The affected area of the skin becomes crusty and dry, and after a few weeks, all symptoms vanish. If the exposed area is thoroughly washed with cold, running water immediately after contact, the poison may not penetrate the skin.

If the symptoms do develop, they can be relieved with applications of over-the-counter medications such as Domeboro or calamine lotion. If the symptoms are severe, and especially if the area around the eyes is involved, a physician should be consulted. He may prescribe an application or an injection of cortisone.

The best way to avoid the unpleasantness of a poison ivy attack is to learn to recognize the plant and stay away from it. Children especially should be warned against putting the leaves and berries in their mouths.

Poison oak and poison sumac produce somewhat the same symptoms and should also be avoided.

Under no circumstances should these plants be burned to eliminate them, because the inhaling of the contaminated smoke even from a distance can cause a serious case of poisoning. The application of special sprays, if the instructions are followed carefully, will get rid of the plants without affecting people or the neighborhood greenery.


These are large, irregularly shaped swellings on the skin that burn and itch. The cause is unknown, but allergic reactions to certain foods and medicine or to insect bites have been suggested as possible causes. The swellings of hives usually disappear within a day or so, but they can be very uncomfortable while they last. The itching and burning can often be relieved by applying cold water and a calamine solution. However, some people are sensitive to cold and develop wheals when subjected to intense cold. Commercial preparations containing surface anesthetics are seldom effective and may cause allergic reactions.

If the outbreak of hives can be traced to a specific food, such as shellfish or strawberries, the food should be eliminated from the diet. If a medicine such as penicillin or a sulfa drug is the cause, a physician should be told about the reaction.


This condition is an allergic reaction that produces itching, swelling, blistering, oozing, and scaling of the skin. It is more common among children than among adults and may sometimes cover the entire body, although the rash is usually limited to the face, neck, and folds of the knees and elbows. Unlike contact dermatitis, it is likely to be caused by an allergy to a food or a pollen or dust. Advertised cures for eczema cannot control the cause and sometimes make the condition worse. A physician should be consulted if the symptoms are severe, particularly if the patient is an infant or very young child.


The technical name for the localized or general sensation on the skin that can be relieved by scratching is pruritus . Itching may be caused by many skin disorders, by infections, by serious diseases such as nephritis or leukemia, by medicines, or by psychological factors such as tension. A physician should always be consulted to find the cause of persistent itching, because it may be the symptom of a basic disorder. Repeated scratching may provide some relief, but it can also lead to infection.

Anal Pruritus

If itching in the anal area is so severe that only painful scratching will relieve it, the condition is probably anal pruritus . It is often accompanied by excessive rectal mucus that keeps the skin irritated and moist. This disorder is most commonly associated with hemorrhoids, but many other conditions, such as reactions to drugs, can cause it. Anxiety or tension can also contribute to it. Sitz baths with warm water are usually recommended. Every effort should be made to reduce scratching and to keep the anal skin clean and dry. Cortisone cream may be prescribed in persistent cases.

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