Eczema refers to a group of inflammatory skin conditions. Doctors and researchers aren’t quite sure what causes eczema, but they believe it’s related to a combination of an overactive immune system and environmental and genetic factors. Eczema isn’t contagious and can’t be passed from one person to another.1
By learning about what causes eczema and how to recognize common signs, you can get treatment as soon as possible to get relief from your dry, itchy skin and avoid complications.
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What Is Eczema?
Eczema is an umbrella term used to describe a group of inflammatory skin conditions. There are many types of eczema, each affecting different areas of the body. You may see the terms atopic dermatitis and eczema used interchangeably, but it’s important to note that not all eczema cases are atopic dermatitis.
Eczema vs. Psoriasis: Differences and Similarities
Atopic Dermatitis
The most common type of eczema in the United States is atopic dermatitis, which affects over 9.6 million children and 16.5 million adults.2 It tends to develop in young children (around 5 years old) and often continues for life. However, anyone can develop atopic dermatitis at any age.
In atopic dermatitis, the immune system is overactivated and creates too much inflammation that damages the skin. Many people with atopic dermatitis have a damaged or compromised skin barrier, which prevents it from holding onto moisture as well as it should. Studies show that this is due to mutations in the filaggrin protein, which is part of a normal and healthy skin barrier.
When your skin barrier is compromised, it’s much more vulnerable to irritating substances found around you. Common atopic dermatitis triggers for many people include:3
- Soaps, lotions, and ointments containing harsh chemicals that dry out the skin
- Environmental allergies to dust and dust mites, pollen, mold, or pet dander
- Bathing or showering too often, which can dry out the skin
- Wearing clothing made from irritating or scratchy materials, such as wool
- Illnesses like the common cold or flu
- Periods of emotional stress
- Cold, dry air and wind
Atopic dermatitis is a chronic and often lifelong condition that is characterized by periods of worsening symptoms (known as flares) and periods of relief (remission). During a flare, your skin may become extremely dry, red, and itchy. If you scratch an eczema rash, the skin may begin to bleed, ooze, or leak clear fluid. The most commonly affected areas include the elbows and knees, hands, neck, feet, and ankles.4
The biggest risk factor for developing atopic dermatitis is having other allergies or asthma. Doctors and researchers have developed a theory known as the “atopic march” or “allergic march” to describe how allergies naturally progress in children through adulthood.5,6 Around 50 percent of infants and toddlers with eczema eventually develop food allergies, seasonal allergies, and/or asthma. Having a family history of any of these allergic conditions also increases your risk of atopic dermatitis.4
Contact Dermatitis
Have you ever developed red, dry, itchy skin after using a brand of makeup or a certain type of laundry detergent? This is known as contact dermatitis, and it can often look similar to atopic dermatitis. However, contact dermatitis is skin cell damage caused by an irritating substance or allergy rather than an overactive immune system. It’s most common in people who are exposed to irritating substances on a daily basis.7
Around 80 percent of contact dermatitis cases are caused by skin irritants like soaps, hair dye, clothing fabrics, bleach, or certain metals in jewelry. The other 20 percent of cases are known as allergic contact dermatitis. One example is a poison ivy rash that’s caused by your immune system responding to an irritating oil. Your immune cells create an allergic response by releasing histamine, causing a red, itchy skin rash for a few days.7
Neurodermatitis
Neurodermatitis — also known as lichen simplex chronicus — is another common type of eczema that affects around 12 percent of people in the U.S.8,9 It tends to only affect a few areas of the skin, as opposed to atopic dermatitis, which can affect the entire body. Neurodermatitis is caused by an intense urge to scratch your skin. As you continue scratch, the skin becomes more irritated and itchy, creating a never-ending “itch-scratch cycle” that’s hard to break without treatment.
Certain risk factors increase your risk of developing neurodermatitis. Women and those with obsessive-compulsive disorder (OCD), anxiety disorders, and a family history of inflammatory skin conditions are more likely to develop the condition. Adults between the ages of 30 and 50 are also at the highest risk.9
Neurodermatitis tends to affect the skin around the hands, elbows, wrists, feet, ankles, neck, shoulder, and scalp. It can appear as red, gray, or brown patches of thickened skin. Continuous scratching may cause bleeding and scarring over time.
Seborrheic Dermatitis
Seborrheic dermatitis is a chronic type of eczema that primarily affects the scalp and other areas of the skin with sebaceous glands. These glands produce sebum, an oily substance that forms a protective barrier over the skin. Malassezia yeast is a microorganism that lives on our skin and feeds off of sebum. Some people have an overactive immune system that reacts to this yeast, causing inflammation, irritation, and fungal infections.10,11
The most common symptoms of seborrheic dermatitis are dandruff (white skin flakes), greasy white or yellow scales, and red or brown skin rashes. According to the National Eczema Foundation, as many as 30 percent of people will develop seborrheic dermatitis in their lifetime, especially adults between the ages of 30 and 50. It’s also more common in people with acne, psoriasis, and rosacea.12
Dyshidrotic Eczema
Dyshidrotic eczema causes pompholyx, or tiny red, itchy blisters, to form on the palms of your hands and soles of your feet.13 Some people only have a dyshidrotic eczema flare once, while others live with it as a lifelong condition. It’s more common in people who also have atopic dermatitis and allergies and those who work with cement or metal for a living. Dyshidrotic eczema appears to affect adults in their 20s to 40s.14
Stasis Dermatitis
Stasis dermatitis is a type of eczema that develops in people with chronic venous insufficiency (CVI) or poor circulation in the legs.15 CVI is caused by damaged blood vessels and valves that allow blood to pool in the legs rather than flow back toward the heart. Over time, the increase in blood pressure in the legs causes smaller blood vessels in the skin to burst, causing:
- Red, gray, brown, or purple skin discoloration
- Extremely dry, scaly skin
- Itchiness
- Open sores or ulcers (known as venous ulcers)
Most people who develop stasis dermatitis are at least 50 years old and have an underlying health condition such as:
- High blood pressure
- Kidney disease or failure
- Heart disease or failure
- Varicose veins or a history of blood clots
- Obesity
Nummular Eczema
Nummular eczema or discoid eczema is characterized by round, dry, itchy patches of skin that are similar in shape and size to coins. When a flare first begins, nummular eczema appears as tiny blisters or bumps. Eventually, the bumps form a round, raised crust that may be pink, red, or brown, depending on your skin tone. Nummular eczema is found on the lower legs, forearms, and hands, and it tends to affect the same place during each flare.16
People with nummular eczema typically have other types of eczema, including atopic dermatitis, contact dermatitis, or stasis dermatitis. Having a damaged skin barrier from another type of eczema triggers nummular eczema flares more easily, especially from hot, dry air, skin infections or injuries, or emotional stress.17
Men over the age of 50 and women under the age of 30 are at the highest risk of developing nummular eczema. It rarely occurs in children, but when it does, it’s usually associated with severe cases of atopic dermatitis.
How Is Eczema Diagnosed?
If you’ve noticed any new eczema symptoms, it’s best to make an appointment with your doctor or a dermatologist who specializes in treating skin conditions. They’ll perform a physical exam and run some additional tests to make a diagnosis.18
Medical History and Physical Exam for Eczema
Your doctor will likely begin by taking your medical history and asking if you have any family history of eczema, seasonal allergies, food allergies, or asthma. They’ll also ask about when your symptoms began and whether any triggers make your symptoms worse. A physical exam will also be conducted to look at the affected areas of skin to note their location and what the rashes, crusts, or scales look like.
If you’re not experiencing an eczema flare during your appointment, be sure to let your doctor know and perhaps show them photos of what your skin looks like during a flare.
Patch Testing for Eczema
If your doctor believes you have contact dermatitis or your symptoms are caused by exposure to a specific substance, they may do patch testing. During this test, your dermatologist or allergist places small drops of liquid with different allergens onto your skin (typically your back). The drops soak into your skin and are left there for 48 hours to see if you react — you’ll likely have red, raised, itchy bumps on your skin. Your doctor will check to see what, if any, substances caused a reaction. Some allergens take longer to react to, so you’ll likely have to visit your doctor again in 4 to 7 days.19
Skin Biopsy for Eczema
In most cases, your doctor can make a diagnosis using just your list of symptoms and physical exam results. However, they may also choose to perform a skin biopsy, where they take a small piece of skin to look at under a microscope. Your doctor will numb the area being biopsied, then use a scalpel or a punch tool to remove the piece of skin. It’s then sent to a laboratory, where a pathologist will determine whether you have atopic dermatitis or another type of eczema or skin condition.20
Complications of Eczema
If you have eczema, it’s important to find what treatments work best for you to lower your risk of developing complications. People with eczema are at a higher risk of developing skin infections and experiencing skin changes and sleep problems.
Skin Infections with Eczema
The disrupted skin barrier and dry, cracked skin in eczema lets pathogens in much more easily than healthy skin. Bacterial, fungal, and viral infections all activate your immune system, leading to additional inflammation, redness, and itchiness. People with eczema are at an increased risk of:21-24
- Bacterial infections with Staphylococcus aureus and Streptococcal pyogenes, which cause pus-filled blisters and sores
- Fungal infections with Malassezia yeast on the head, face, and neck, or ringworm
- Viral infections with pox viruses and herpesviruses that cause bumps or red, black, or purple pus-filled blisters, high fever, and chills
Skin Changes with Eczema
Chronic inflammation from eczema can permanently change your skin’s texture and color. This is known as post-inflammatory hyperpigmentation (skin darkening) or hypopigmentation (skin lightening). People with darker skin tones are more likely to experience skin color changes that can take several months to return to normal.4
Many people living with neurodermatitis develop tough, thick, or leathery skin from constantly itching and scratching. The only way to prevent skin changes is to break the itch-scratch cycle with proper treatment that helps the skin heal.25
Sleep Problems with Eczema
Sleep can be hard to come by when you’re constantly itching and scratching your skin. Many people with eczema struggle with sleeping — studies estimate that up to 80 percent of children and 90 percent of adults with eczema experience sleep disturbances.26
When you don’t get enough sleep, you don’t perform as well at work or school, and your interpersonal relationships may be impacted. You’re also at an increased risk of developing diabetes, heart disease, and mental health conditions.
Mental Health Conditions with Eczema
Inflammatory skin conditions are consistently linked to mental health conditions like anxiety and depression. Some people with eczema feel embarrassed about their skin, leading to emotional distress. According to a survey from the National Eczema Association, over 30 percent of people with atopic dermatitis have anxiety and/or depression.27
Can Eczema Be Prevented?
Unfortunately, eczema can’t be prevented, and there’s currently no cure available. It can be managed with a combination of topical, oral, and injectable medications that dampen the immune system and calm inflammation.28
Eczema is often a life-long condition, but there are steps you can take to help prevent flares. The key to preventing flares is to keep your skin as moisturized as possible. To learn more about how eczema is treated, along with tips for locking moisture into your skin, read here .
Resources for Living with Eczema
If you or a loved one is living with eczema, there are several resources and support groups available to you. They offer information and the opportunity to find a community with those who are also living with eczema.
