Each type of dermatitis may look a little different and tends to occur on different parts of your body. The most common types of dermatitis include:
- Atopic dermatitis (eczema). Usually beginning in infancy, this red, itchy rash most commonly occurs where the skin flexes — inside the elbows, behind the knees and the front of the neck. When scratched, the rash can leak fluid and crust over. People with atopic dermatitis may experience improvement and then flare-ups.
- Contact dermatitis. This rash occurs on areas of the body that have come into contact with substances that either irritate the skin or cause an allergic reaction, such as poison ivy, soap and essential oils. The red rash may burn, sting or itch. Blisters may develop.
- Seborrheic dermatitis. This condition causes scaly patches, red skin and stubborn dandruff. It usually affects oily areas of the body, such as the face, upper chest and back. It can be a long-term condition with periods of remission and flare-ups. In infants, this disorder is known as cradle cap.
When to see a doctor
See your doctor if:
- You're so uncomfortable that you are losing sleep or are distracted from your daily routines
- Your skin becomes painful
- You suspect your skin is infected
- You've tried self-care steps without success
A number of health conditions, allergies, genetic factors and irritants can cause different types of dermatitis:
- Atopic dermatitis (eczema). This form of dermatitis is likely related to a mix of factors, including dry skin, a gene variation, an immune system dysfunction, bacteria on the skin and environmental conditions.
- Contact dermatitis. This condition results from direct contact with one of many irritants or allergens — such as poison ivy, jewelry containing nickel, cleaning products, perfumes, cosmetics, and even the preservatives in many creams and lotions.
- Seborrheic dermatitis. This condition may be caused by a yeast (fungus) that is in the oil secretion on the skin. People with seborrheic dermatitis may notice their condition tends to come and go depending on the season.
A number of factors can increase your risk of developing certain types of dermatitis. Examples include:
- Age. Dermatitis can occur at any age, but atopic dermatitis (eczema) usually begins in infancy.
- Allergies and asthma. People who have a personal or family history of eczema, allergies, hay fever or asthma are more likely to develop atopic dermatitis.
- Occupation. Jobs that put you in contact with certain metals, solvents or cleaning supplies increase your risk of contact dermatitis. Being a health care worker is linked to hand eczema.
- Health conditions. You may be at increased risk of seborrheic dermatitis if you have one of a number of conditions, such as congestive heart failure, Parkinson's disease and HIV.
Scratching the itchy rash associated with dermatitis can cause open sores, which may become infected. These skin infections can spread and may very rarely become life-threatening.