Skin Allergies

skin allergies

Skin Allergies

The most general skin allergies contain contact allergic dermatitis and urticarial reactions (hives). Contact allergic dermatitis can have a variety of presentations, mostly commonly appearing as red, scaly itchy marks that can blister and weep in severe cases. The distribution of this rash on the body can often give clues regarding its underlying reason. There are many other allergens that reason contact dermatitis and certain occupations such as hairdressers and nurses are at enlarged risk of developing these reactions.

Another common contact allergen is the preservative Methylchloroisothiozolinone (MCI) and Methylisothiozolinone (MI), also sometimes referred to as Kathon. This allergen is a preservative found in many bathroom products including shampoos, conditioners, washes, wet wipes, cosmetics, sunscreens and moisturizing creams. Some paints also contain this preservative. Patch testing is the formal method of allergy testing for contact allergic dermatitis. The repeat open application test (ROAT) is a self-directed way of testing a product/allergen to see whether you react. This involves applying a small amount of a suspect product on the inner forearm twice daily for a week to see whether an itchy rash develops.

Something touches your skin, and your immune system thinks it’s under attack. It overreacts and sends antibodies to help fight the invader, called an allergen. The result is a red, itchy rash where the substance landed.


Your doctor calls this contact dermatitis. There are two types:

  • Irritant contact dermatitis is reason by chemicals like harsh cleaners.
  • Allergic contact dermatitis is just like it sounds — your body reacts to an allergy trigger.

People who have allergies react to things that wouldn’t bother most others. Anything from plants like poison ivy to dyes and fragrances found in everyday products might be allergens.

You could also have an allergic reaction to something in the air that settles on your skin, like pollen, chemical sprays, powders, fibers, or cigarette smoke. This is called airborne contact dermatitis, and it mostly occurs on your eyelids, head, and neck. It can be hard for doctors to diagnose because it doesn’t look that different from the other type. Skin allergies can also reason hives and swelling deep in your skin, called angioedema.

What Causes Skin Allergies?

It takes at least 10 days to become sensitive to something after your first contact with it. You might even be capable to touch something for years before you have an allergic reaction to it.

But once you develop an allergy, you could have a reaction within a few minutes of coming into contact with it. Or it might take a day or two.

The most common causes of skin allergies include:

  • Nickel, a metal used in jewelry and snaps on jeans, makeup, lotions, soaps, and shampoos
  • Sunscreens and bug sprays
  • Medications you put on your skin, like antibiotics or anti-itch creams
  • Fragrances
  • Cleaning products
  • Plants, including poison ivy