How does eczema start?

The cause of eczema is not exactly known. However, eczema seems to start when a person comes in contact with a trigger or allergen. An allergen may be due to one’s genes or an external factor from the environment. Triggers can include stress, food, chemicals, or the environment.

People with a family history or diagnosis of allergic conditions, such as asthma or hay fever, may have a higher risk of eczema.

When the body contacts an allergen, the immune system assumes it is a foreign invader that can harm the body. The immune system then activates its defense system and fights the normal skin barrier. The inflammation or flare-up on the skin’s surface is a response to the immune system.

People may experience eczema symptoms differently. Although itching is a common symptom, eczema may also cause several other symptoms in different areas of the body. These symptoms include:

• dry skin
• bumps
• scaly, rusty patches

In lighter skin tones, eczema can appear as red rashes. In darker skin tones, the skin may appear ashen with gray, dark brown, or purple patches.

If a person suspects they have eczema, they or their caregiver can speak with a dermatologist. This doctor specializes in treating skin conditions. A dermatologist can evaluate a person’s symptoms and make a diagnosis. They can develop a symptom management plan and propose different treatment options.

Eczema may appear differently depending on the type of eczema and the age of the person affected.

Atopic dermatitis

Atopic dermatitis is the most common type of eczema. Itching is a prominent symptom of the condition when it starts.

This type of eczema may affect infants, babies, toddlers, and adults in the following ways:

• In infants: Eczema usually appears on the face, cheeks, chin, forehead, and scalp. It can also spread to other body areas. The skin at this stage also tends to look more inflamed and may appear “weepy.”
• In babies: Eczema often appears on the baby’s elbows and knees — places that are easy to scratch or rub when crawling.
• In toddlers: Eczema can appear as dry, crusted sores in the crease of elbow or knee folds or on the wrists, hands, or ankles. It frequently affects the face in children. A toddler’s skin may look dry and scaly at this stage and become thick with deeper lines.
• In adults: Eczema can occur as rashes anywhere in the body.

Contact dermatitis

Contact dermatitis may initially occur as red, irritated, scaly patches in any area that comes in contact with an allergen or irritant, such as latex, metal, or a chemical.

This type of eczema may affect babies, toddlers, and adults in similar ways:

• In babies: When exposed to an allergen, the exposure site becomes itchy and scaly within hours or up to a few days, but it may also spread to other areas. There may be blisters and swelling.
• In toddlers: Red, itchy, and scaly patches can form within hours or up to a few days after exposure to an allergen. The patches can form on the:
  • hands
  • feet
  • arms
  • legs
  • face
• In adults: It can appear as blisters in the same exposure areas as in toddlers.

Dyshidrotic eczema

Dyshidrotic eczema may appear as small, fluid-filled blisters on the hands, feet, and toes. This can cause skin cracks, flakes, and scales on the affected parts.

This type of eczema may affect babies, toddlers, and adults in the following ways:

• In babies and toddlers: Dyshidrotic eczema is not common in babies and toddlers. It is more common in older children and adults.
• In adults: It can start as small blisters on the hands, feet, and edges of the fingers and toes.

Nummular eczema

Nummular, or discoid, eczema forms oval, coin-shaped patches on adult skin. Patches can become infected, inflamed, and sensitive over time.

Children younger than 5 years rarely develop the condition.

Seborrheic dermatitis

In the beginning, people with seborrheic dermatitis often experience a constant itch and rash around the scalp, alongside other eczema symptoms.

This type of eczema may affect babies, toddlers, and adults in the following ways:

• In babies: When seborrheic dermatitis occurs in babies, it is often called cradle cap. It can start as greasy patches on the scalp and groin folds. It can start as young as 2 months and usually improves between 8 and 12 months of age.
• In toddlers: Toddlers rarely develop seborrheic dermatitis.
• In adults: Seborrheic dermatitis can appear near the scalp and other parts of the face. It can also spread to the following areas:
  • mid-chest
  • upper back
  • armpits
  • groin

Stasis dermatitis

Symptoms of stasis dermatitis include red or purple scales. It develops from poor blood circulation in the legs.

According to the American Academy of Dermatology (AAD), stasis dermatitis rarely occurs in other body parts other than the legs.

The AAD also states venous insufficiency increases with age. Therefore, it does not tend to occur in toddlers or infants.

It is most common in adults aged 50 and older. It usually appears as red or dark brown speckles on the legs.

Neurodermatitis

Neurodermatitis affects about 12% of the U.S. population, estimates the National Eczema Association. People with psoriasis and other dermatitis have a greater risk of neurodermatitis.

Infants and toddlers rarely develop neurodermatitis.

In adults, symptoms are often visible as skin lines, scales, or discoloration. It is most common on the:

• feet
• ankles
• hands
• wrists
• elbows
• shoulders
• neck
• scalp

The following factors may trigger eczema in adults and children:

• extended exposure to extreme temperatures
• certain types of soaps, bath products, and body washes
• shampoos
• laundry detergents and fabric softeners
• certain fabrics, such as wool and polyester, in clothing and sheets
• surface cleaners and disinfectants
• fragrances in candles
• metals, especially nickel, in jewelry or utensils
• dust mites

A person can discuss their potential eczema triggers with a primary care doctor or dermatologist to find ways to manage the condition.

Eczema can appear as inflamed or itchy patches of skin on various body parts, depending on the eczema type. Varying age groups may experience symptoms differently.

Exposure to specific triggers can cause symptoms to appear. However, eczema also has a genetic predisposition. If a person has other allergic conditions, they may have a higher risk of developing eczema.

A person can discuss ways to manage and treat the condition with their doctor.