How Itching Is Related to Skin Allergies?
Rashes and itching of the skin are the most common symptoms of skin allergies. However, not all the conditions that are causing this kind of symptoms are related to an allergy. In fact, there are various dermatologic diseases that lead to an itchy rash, including fungal, bacterial, and viral infections, insect bites, as well as autoimmune conditions.
Nevertheless, allergic diseases remain the major cause of skin rashes. There are many types of skin allergies, while the most commonly occurring are atopic dermatitis, hives, and contact dermatitis.
Atopic dermatitis is an allergic skin disease that is more commonly referred to as “eczema”. This type of allergy mostly affects young children, though it might also occur in adolescents and adults. Eczema, the rash caused by atopic dermatitis, is normally triggered by scratching and appears in the areas of the skin that are scratched. Thus, in infants, eczema affects the areas of the chest, cheeks, and scalp, while older children and adults may experience it on the inner side of the elbows and behind the knees. In some cases, the rash also occurs on the face, neck, hands, feet, or back.
The rash caused by atopic dermatitis is red-colored, with small itching, flaking and oozing blisters. Itchiness causes a strong need to scratch, which often leads to excoriations and broken skin.
The symptoms of atopic dermatitis can be treated at home. However, specialists recommend visiting an allergist or immunologist for a thorough evaluation, since atopic dermatitis has been related to food allergies in children.
Urticaria and Angioedema
Urticaria is another type of skin allergies, which unlike atopic dermatitis, can occur at any age. The condition is more commonly known as hives. It causes an itchy rash that comes in the form of raised red bumps of various sizes and shapes. The rash is temporary, usually lasting only for a few minutes or a few hours.
The itching caused by the rash can be extremely annoying. However, excoriations and areas of broken skin caused by aggressive scratching are not typical for urticaria.
There are two types of urticaria: acute, that lasts less than six weeks, and chronic, that lasts more than six weeks. In certain cases, urticaria is accompanied by another condition called angioedema.
Angioedema is a medical term for swelling, and it usually affects the lips, eyes, hands or feet. It causes burning and tingling sensation in the affected areas. Sometimes, angioedema may lead to anaphylaxis – a life-threatening condition characterized by severe swelling blocking the ability to breath.
Contact dermatitis is a type of skin allergy that occurs after a direct contact between the skin and an allergenic substance. This condition causes an extremely itchy rash that can ooze and crust.
Substances that can potentially cause an allergic reaction include plants, cosmetics, hair dye, metals, topical medications, as well as dental materials.
The rash caused by contact dermatitis is visually similar to that of atopic dermatitis. The main difference is that it typically appears in the areas of contact with the allergenic chemical. Thus, the contact dermatitis rash is most commonly present on the face, neck, wrists or hands, feet, piercing holes, and waistline.
The diagnosis of contact dermatitis can be made based on a patch test. However, the cause of an allergic reaction is often difficult to identify.