There are several different kinds of dermatitis, all of which are effectively red rashes with a few different characteristics. The biggest difference, however, in the many kinds of dermatitis are the causes of those rashes. Contact, atopic, and seborrheic are three common types of dermatitis that can also be described as eczemas. Here is a look at what causes these three.
Contact Dermatitis
Just as there are different types of dermatitis, there are different types of contact dermatitis. The most common of these are allergic contact dermatitis and irritant contact dermatitis. Any type of contact dermatitis appears because your skin comes into contact with a substance that doesn’t agree with it.
If the rash is allergic contact dermatitis, the rash ultimately develops because of the body’s sensitivity to a particular substance. It can take coming into contact with the substance multiple times for the reaction to occur; additionally, it can take a few days for the rash to appear. Sometimes it may take coming into contact with the sun for the sensitivity to kick in. This is called photoallergic contact dermatitis.
Common allergens include:
- Plants (such as poison ivy)
- Airborne insecticides
- Metals (particularly nickel, cobalt, and chromium salts)
- Fragrance chemicals
- Formaldehyde
- Personal care products
Irritant contact dermatitis is virtually the same thing, except that nearly any substance can cause it. Some things are more likely to result in the rash because of their chemical makeup. Here are some examples of irritants:
- Bleach
- Solvents
- Burdock
- Airborne substances (like sawdust)
- Isopropyl alcohol
In other cases the irritation is simply a result of too much contact—i.e., diaper rash or the itchy, tender rash that appears when you wash your hands too frequently.
Atopic Dermatitis
Atopic dermatitis is more commonly known as general eczema. Atopic is a chronic condition resulting in inflamed and itchy rashes often in the bend of the knees and elbows or on the neck or cheeks. Research suggest a family history of hay fever and/or asthma is often associated with atopic dermatitis in what is considered the atopic triad. Beginning in childhood, atopic dermatitis is triggered in flares for a few months at a time before subsiding again. Although the exact cause is still questionable, ultimately the immune system overreacts. Other factors that may impact atopic dermatitis include bacteria, dry skin, particular genes, or the environment.
Seborrheic Dermatitis
Seborrheic dermatitis occurs most often as an oily red rash, sometimes with white or yellowish dandruff-like flakes on the scalp. It may also present on other oily areas like the back or nose. While it can be chronic in adults, infantile seborrheic dermatitis (cradle cap) usually clears up after the infant’s skin has a few months to adjust to the change in environmental conditions. The exact cause of seborrheic dermatitis has not yet been discovered either. However, it is suspected that three major factors contribute to its development: environmental conditions (dry air, etc), a psoriasis-type inflammatory response, and an overgrowth of microscopic fungi in the skin.
