How do you classify eczema?

Eczema can be classified in several ways, often based on its underlying causes, clinical presentation, or location. However, a common and clinically useful classification categorizes eczema into several distinct types, each with its own characteristic features. It is important to note that different types of eczema can sometimes overlap or co-exist in an individual.

Major Types of Eczema

The seven most commonly recognized types of eczema are:

• Atopic Dermatitis (Atopic Eczema): This is the most prevalent and chronic form of eczema, often beginning in infancy or early childhood. It is characterized by dry, intensely itchy patches of skin that can crack, ooze, or form crusts. Atopic dermatitis is strongly linked to a genetic predisposition and often occurs alongside other allergic conditions like asthma and allergic rhinitis (hay fever).
• Contact Dermatitis: This type develops when the skin comes into direct contact with a substance that causes either irritation or an allergic reaction.
  • Irritant Contact Dermatitis (ICD): Caused by direct damage to the skin from irritants like harsh soaps, chemicals, or prolonged exposure to water.
  • Allergic Contact Dermatitis (ACD): An immune-mediated, delayed hypersensitivity reaction triggered by allergens such as nickel, certain cosmetics, or poison ivy.
• Dyshidrotic Eczema (Pompholyx): This type is characterized by small, intensely itchy blisters that typically appear on the palms of the hands, soles of the feet, and sides of the fingers and toes. It is often linked to stress, allergies, or exposure to certain metals.
• Neurodermatitis (Lichen Simplex Chronicus): This is characterized by localized, intensely itchy patches of thickened, leathery skin. It develops from a cycle of scratching and rubbing in a particular area, often due to an underlying itch sensation, stress, or other dermatological conditions.
• Nummular Eczema (Discoid Eczema): Characterized by coin-shaped or oval patches of irritated, itchy skin, which can be crusty or scaly. These patches can appear anywhere on the body but are commonly found on the arms, legs, and trunk.
• Seborrheic Dermatitis: This primarily affects areas of the body with a high concentration of sebaceous (oil) glands, such as the scalp, face (especially around the nose and eyebrows), and chest. It manifests as red, greasy, scaly patches and is a common cause of dandruff.
• Stasis Dermatitis: This type occurs on the lower legs and is typically associated with poor circulation, often seen in individuals with venous insufficiency, varicose veins, or swelling. Symptoms include redness, itching, scaling, and skin discoloration, often brownish.

Classification of Eczema

Here's a detailed classification table summarizing the key characteristics of each type:

Type of Eczema	Key Characteristics	Common Locations	Primary Causes/Triggers
Atopic Dermatitis	Chronic, intensely itchy, dry patches; often red, gray, brown, or purplish depending on skin tone; can ooze/crust.	Face, hands, inside elbows, behind knees, generalized.	Genetic predisposition, immune system dysfunction, environmental factors (allergens, irritants).
Contact Dermatitis	Rash, redness, swelling, itching, sometimes blisters; localized to exposed area.	Area of contact with irritant/allergen (e.g., hands, wrists, face).	Direct contact with irritants (soaps, chemicals) or allergens (nickel, poison ivy).
Dyshidrotic Eczema	Small, clear, intensely itchy blisters; dry, scaly patches when blisters resolve.	Palms of hands, soles of feet, sides of fingers/toes.	Stress, allergies, sweat, exposure to metals.
Neurodermatitis	Thickened, leathery, intensely itchy patches; often single or a few distinct patches.	Neck, wrists, ankles, scalp, genital area.	Repetitive scratching/rubbing due to underlying itch, stress.
Nummular Eczema	Coin-shaped or oval patches; itchy, may ooze or crust.	Arms, legs, trunk.	Dry skin, skin injury (insect bites), stress.
Seborrheic Dermatitis	Red, greasy, scaly patches; flaking (dandruff).	Scalp, face (eyebrows, sides of nose), chest, groin.	Overgrowth of Malassezia yeast, genetics, stress, hormonal changes.
Stasis Dermatitis	Red, itchy, scaly skin on lower legs; swelling, brown discoloration (hyperpigmentation), sometimes ulcers.	Lower legs, ankles.	Poor blood circulation (venous insufficiency).

While the classification above covers the most common types, other forms or specific manifestations of eczema exist, such as hand eczema (which can be a manifestation of various types), asteatotic eczema (due to extreme dryness), or autoeczematization (an allergic reaction to an infection or inflammation elsewhere on the body).