When is a skin rash, swollen or itchy skin due to allergies?

Eczema (atopic dermatitis)

Eczema, also known as atopic dermatitis, affects between 10 and 20 percent of children and 1 to 3 percent of adults. A common symptom of eczema is dry, red, irritated, and itchy skin. Sometimes, especially when infected, the skin may have small, fluid-filled bumps that ooze a clear or yellowish liquid. People with eczema often have a family history of allergies.

Contact Dermatitis

Contact dermatitis is a reaction that appears when the skin comes in contact with an irritant or an allergen. Symptoms can include a rash, blisters, itching and burning.

Soaps, laundry detergents, fabric softeners, shampoos — or even excessive exposure to water — can all cause contact dermatitis. Other items that can cause a reaction are metals (such as nickel, a component of stainless steel and other alloys used to make costume jewelry), adhesives, nail polish, topical medications, plants and latex gloves.

Poison ivy, jewelry made of certain metals (especially nickel or gold) and sunscreen all can cause contact dermatitis — a skin condition that results from exposure to something to which you’re either sensitive or allergic.

Other common irritants or allergens include:

  • Fragrant soaps
  • Rubber
  • Certain deodorants
  • Bleach
  • Hand sanitizers

Hives (Urticaria)

Hives (urticaria) are red bumps or welts that appear on the body. The condition is called acute urticaria. If the hives last more than 6 weeks, it is considered chronic urticarial. Acute urticaria is most commonly caused by exposure to an allergen or due to infection. The cause of chronic urticaria is largely unknown.

For new onset of hives, or acute urticarial, the hives can be caused by:

  • Recent illness
  • Medication use
  • IV radiocontrast media
  • Foods
  • New perfumes, hair dyes, detergents, lotions, creams, or clothes
  • Exposure to new pets (dander), dust, mold, chemicals, or plants
  • Sun or cold exposure