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Atopic Dermatitis

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Medical Author:

Nili N. Alai, MD, FAAD

Nili N. Alai, MD, FAAD

Dr. Alai is an actively practicing medical and surgical dermatologist in south Orange County, California. She has been a professor of dermatology and family medicine at the University of California, Irvine since 2000. She is U.S. board-certified in dermatology, a 10-year-certified fellow of the American Academy of Dermatology, and Fellow of the American Society of Mohs Surgery.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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What is atopic dermatitis?

Atopic dermatitis is a very common, often chronic (long-lasting) skin disease that affects a large percentage of the world's population. It is also called eczema, dermatitis, or atopy. Most commonly, it may be thought of as a type of skin allergy or sensitivity. The atopic dermatitis triad includes asthma, allergies (hay fever), and eczema. There is a known hereditary component of the disease, and it is seen more in some families. The hallmarks of the disease include skin rashes and itching.

The word "dermatitis" means inflammation of the skin. "Atopic" refers to diseases that are hereditary, tend to run in families, and often occur together. In atopic dermatitis, the skin becomes extremely itchy and inflamed, causing redness, swelling, cracking, weeping, crusting, and scaling. Dry skin is a very common complaint and an underlying cause of some of the typical rash symptoms.

Although atopic dermatitis can occur in any age, most often it affects infants and young children. In some instances, it may persist into adulthood or actually first show up later in life. A large number of patients tend to have a long-term course with various ups and downs. In most cases, there are periods of time when the disease is worse, called exacerbations or flares, which are followed by periods when the skin improves or clears up entirely, called remissions. Many children with atopic dermatitis enter into a permanent remission of the disease when they get older, although their skin may remain somewhat dry and easily irritated.

Multiple factors can trigger or worsen atopic dermatitis, including dry skin, seasonal allergies, exposure to harsh soaps and detergents, new skin products or creams, and cold weather. Environmental factors can activate symptoms of atopic dermatitis at any time in the lives of individuals who have inherited the atopic disease trait.

What is the difference between atopic dermatitis and eczema?

Eczema is used as a general term for many types of skin inflammation (dermatitis) and allergic-type skin rashes. There are different types of eczema, like allergic, contact, irritant, and nummular eczema. Several other forms have very similar symptoms. The diverse types of eczema are listed and briefly described below. Atopic dermatitis is typically a more specific set of three associated conditions occurring in the same person including eczema, allergies, and asthma. Not every component has to be present at the same time, but usually these patients are prone to all of these three related conditions.

Types of eczema

• Contact eczema: a localized reaction that includes redness, itching, and burning where the skin has come into contact with an allergen (an allergy-causing substance) or with an irritant such as an irritating acid, a cleaning agent, or other chemical
• Allergic contact eczema: a red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy or certain preservatives in creams and lotions like Neosporin or Bacitracin
• Seborrheic eczema (also called seborrheic dermatitis or seborrhea): is a very common form of mild skin inflammation of unknown cause that presents as yellowish, oily, scaly patches of skin on the scalp, face, ears, and occasionally other parts of the body. Often this is also called dandruff in adults or "cradle cap" in infants.
• Nummular eczema: coin-shaped (round), isolated patches of irritated skin -- most commonly on the arms, back, buttocks, and lower legs -- that may be crusted, scaling, and extremely itchy
• Neurodermatitis: a very particular type of dermatitis where the person frequently picks at their skin, causing rashes. The underling cause may be a sensitivity or irritation which sets off a cascade of repeated itching and scratching cycles. It may be seen as scratch marks and pick marks on the skin. Sometimes scaly patches of skin on the head, lower legs, wrists, or forearms caused by a localized itch (such as an insect bite) may become intensely irritated when scratched.
• Stasis dermatitis: a skin irritation on the lower legs, generally related to circulatory problems and congestion of the leg veins. It may have a darker pigmentation, light-brown, or purplish-red discoloration from the congestion and back up of the blood in the leg veins. It's sometimes seen more in legs with varicose veins.

Picture of stasis eczema on the leg

• Dyshidrotic eczema: irritation of the skin on the palms of hands (mostly) and less commonly soles of the feet characterized by clear, very deep-seated blisters that itch and burn. It's sometimes described as a "tapioca pudding"-like rash on the palms.