What Is Eczema? Understanding Atopic Dermatitis

Eczema is a group of conditions that cause inflamed, itchy, and irritated skin. The most common type is atopic dermatitis, affecting over 31 million Americans. If you're wondering whether "atopic dermatitis" and "eczema" are the same thing, the answer is that atopic dermatitis is the most prevalent form of eczema, and the terms are often used interchangeably in everyday conversation.

What Is Eczema?

Eczema causes your skin to become dry, red, itchy, and bumpy. It's a chronic condition that tends to flare up periodically, then calm down. The term "eczema" actually refers to several related skin conditions that share similar symptoms, while atopic dermatitis specifically refers to a sensitivity disease similar to asthma in the lungs or hay fever in the sinuses.

Most people with eczema first experience symptoms during childhood—about 80% develop it before age 6. However, eczema can start at any age, including adulthood.

Types of Eczema

There are seven main types of eczema:

• Atopic dermatitis: The most common form, causing itchy, inflamed skin

• Contact dermatitis: Triggered by touching irritants or allergens

• Dyshidrotic eczema: Causes small, itchy blisters on hands and feet

• Seborrheic dermatitis: Affects oily areas like the scalp and face

• Neurodermatitis: Creates thick, scaly patches from repeated scratching

• Nummular eczema: Forms round, coin-shaped spots

• Stasis dermatitis: Occurs in the lower legs due to poor blood circulation

Common Symptoms and Appearance

Eczema symptoms vary by age but typically include:

• Intense itching, especially at night

• Dry, scaly, or thickened skin

• Red to brownish-gray patches

• Small, raised bumps that may leak fluid when scratched

• Swelling and crusting

In infants, eczema usually appears on the face, cheeks, and scalp. As children grow, it typically moves to the creases of elbows and knees. Adults often experience eczema on the hands, feet, arms, and behind the knees. On darker skin tones, eczema may appear dark brown, purple, or gray rather than red.

Who Gets Eczema?

Eczema affects about 10-20% of children and 2-10% of adults worldwide. In the United States, roughly 10.7% of children and 7.2% of adults have the condition. Several factors increase your risk:

• Family history: If one parent has eczema, there's a 60% chance their child will develop it. If both parents have it, the risk jumps to nearly 80%.

• Other allergic conditions: Having asthma or hay fever increases your risk 2-3 times.

• Genetics: Mutations in the filaggrin gene, which helps form your skin's protective barrier, occur in 20-30% of people with eczema.

Research shows that African American/Black individuals have higher rates of eczema (8.6%) compared to other ethnic groups in the U.S., and their symptoms tend to be more severe.

How Eczema Is Diagnosed

Doctors diagnose eczema primarily through a physical examination of your skin. There's no single test for eczema. Your doctor will look at the pattern, location, and appearance of your rash, and ask about your medical and family history.

The diagnostic criteria include three basic items: intense itching, typical appearance and distribution of the rash, and a chronic or recurring course. Sometimes doctors may perform patch testing to identify specific allergens, or rarely, a skin biopsy to rule out other conditions.

The Relationship Between Eczema and Atopic Dermatitis

While "eczema" is an umbrella term for inflammatory skin conditions, "atopic dermatitis" specifically refers to the inherited form linked to allergies. In medical coding, these terms are used interchangeably—both fall under ICD-10 codes L20-L30 for "dermatitis and eczema." For practical purposes, when most people say "eczema," they're referring to atopic dermatitis.

The connection between eczema and other allergic conditions is called the "atopic march." About 50% of people with severe eczema will develop asthma, and 75% will develop allergic rhinitis (hay fever).

When to See a Dermatologist

See a dermatologist if your symptoms persist for more than 2-3 weeks despite using moisturizers and over-the-counter treatments, if the itching is severe enough to disrupt sleep or daily activities, or if you notice signs of infection such as yellow crust, pus-filled blisters, severe pain, or fever. Early treatment can prevent complications and improve quality of life significantly.