Allergic Skin Diseases

Symptoms on the skin such as itching, redness, crusting, swelling and raised areas are usually signs of an allergic condition. These symptoms are, in particular, a reaction of the immune system.

Allergic skin diseases can take many different forms and arise for a variety of reasons.

Atopic dermatitis

Atopy means that a person has an allergic constitution. It can be demonstrated with blood tests. Over time, people with atopic dermatitis may also develop other conditions such as allergic rhinitis and asthma. They are particularly sensitive to woolen clothing. The skin is dry, and excessive use of soap dries it out even further. In these people, sweating causes itching. They should also avoid house dust and animal hair.

Urticaria

Also known as hives, this skin disease presents with red, raised, itchy rashes. In urticaria, the rash on the skin appears suddenly and can take different shapes and sizes, ranging from 2 mm to 30 centimeters. Plaque-like rashes generally stay on the skin for 20 minutes to 3 hours, never longer than 24 hours, and then disappear without leaving a mark, only to reappear on another part of the skin. There are 2 main types of urticaria; the rash looks the same in both types, and only its duration differs.

• Acute urticaria: The rash on the skin usually resolves within about 6 weeks. Although the rash may disappear on its own over time, medication may be needed. In adults, the most common cause of acute urticaria is medication. Nuts such as walnuts and hazelnuts, as well as other foods, can also cause urticaria.
• Chronic urticaria: The rash recurs every day or every few days for longer than 6 weeks. Chronic urticaria is more common in adults. It can be caused by a viral or bacterial infection in the body.

Allergic contact dermatitis

At first there is redness, oozing and itching; later, the oozing is replaced by flaking. It develops after the skin comes into contact with many different agents, such as detergents, cosmetics, plants, medications applied to the skin, light, sun, heat and cold. This rash is the immune system's allergic response to the substance that came into contact with the skin.

Irritant contact dermatitis

This is not allergic, but is caused by an irritating effect. Rashes appear on the areas that come into contact with the irritating substances. The most common cause of this skin disease is detergents, which is why it usually appears on the hands. People with atopy are much more likely to develop allergic and irritant contact dermatitis, and the condition develops shortly after contact with chemical substances.