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Eczema develops when a person’s immune system becomes sensitized to proteins from a source inside or outside the body. The immune system becomes overactive and sets off inflammatory processes that attack the skin.
Eczema is also referred to as dermatitis (which means “skin inflammation”). Dermatitis and eczema are often used interchangeably as general terms for the skin condition. There are many subtypes of eczema, including atopic dermatitis, contact dermatitis, dyshidrotic eczema, hand eczema, and seborrheic dermatitis. Some types of eczema are most common in children, while others are typically seen in adults.
Read more about types of eczema.
Researchers are uncertain why some people develop eczema and others don’t, although they know more now than ever about eczema. Many researchers believe that people who develop eczema have genetic variants that led to an ineffective skin barrier. A damaged skin barrier allows water to evaporate, leading to dryness, and enables irritants to penetrate the skin, setting off immune reactions. People with eczema also have differences in the way their immune systems react. Asthma and food allergies, both related to immune system dysfunction, are common in people with eczema.
Read more about causes and risk factors for eczema.
However eczema develops, its symptoms involve changes to the skin that can cause intense discomfort. Symptoms vary among types of eczema, but most people with eczema experience severe dryness and intense itching and pain. In eczema, the skin can swell, thicken and develop scales, cracks, crusting, or pustules. Eczema can lead to skin infections in some people.
The pain and itching of eczema can lead to insomnia — also called “painsomnia.” Depression and anxiety are common for people with eczema, as in people with all chronic illnesses. People with eczema often face social challenges when others stare or worry whether the condition is contagious. Lack of sleep and social stigma can affect performance at work and school, as well as personal relationships.
Eczema is not fatal. However, in very rare cases, severe forms of eczema can lead to life-threatening complications, such as eczema herpeticum. In eczema herpeticum, eczema leads to a skin infection by a common herpes virus. The resulting rash can easily become infected by bacteria, potentially causing sepsis — an overwhelming immune reaction to infection that can damage tissues and organs, potentially causing death. Cellulitis — a bacterial subcutaneous infection — resulting from eczema can also be dangerous.
Read more about symptoms of eczema.
In the fifth century B.C., Greek physician Hippocrates noted a patient with a skin condition — possibly eczema — that caused chronic itching. In the first century, Roman historian Suetonius wrote that Emperor Augustus suffered from both seasonal respiratory allergies and dry, itchy patches of skin. The word eczema is Greek for “eruption” or “boiling over.”
“De Morbis Cutaneis,” known as the first book on dermatology, was written in 1572 by Italian physician Girolamo Mercuriale. Mercuriale described ”achores,” a condition that caused itching and oozing on the heads of newborn infants. Mercuriale suggested the rash was caused by the mother’s milk. Before the advent of antibiotics in the 1950s, infants with severe eczema often died due to skin infections. Common eczema treatments during this period included bloodletting and laxatives.
In the middle of the 19th century, Viennese dermatologist Ferdinand Schwarzmann von Hebra published the most complete description of eczema at that time. Von Hebra described a chronic, recurring rash that began in infancy and caused intense itching, along with crusting and papules (small, raised swellings). Von Hebra dubbed the rash “prurigo.” For the next several decades, doctors hotly debated the classification of different types of eczema-related diseases and whether they were caused purely by external factors or related to internal, biological dysfunction. During this period, treatments for eczema ranged from starvation (on the theory that eczema was caused by a reaction to food) to the administration of arsenic, mercury, and strychnine. Von Hebra used topical preparations containing tar and rubber wraps to treat his patients.
American allergists Arthur Coca and Robert Cooke introduced the term “atopy” in 1923 to describe an inherited hypersensitivity that resulted in asthma and allergies. Atopy means “without place” in Greek, referring to the uncommon or out-of-the-way nature of the condition. American dermatologists Fred Wise and Marion Sulzberger coined the term “atopic dermatitis” to describe eczema in 1933. Dermatitis comes from the Greek words ”derma” (skin) and ”-itis” (inflammation).
In the 1950s, the introduction of corticosteroids and antibiotics brought some of the first effective treatments for eczema. These medications were first administered orally, but they caused serious side effects when taken for long periods. In 1952, Dr. Sulzberger developed the first topical form of Hydrocortisone to provide effective treatment for eczema with fewer side effects.
American dermatologist Jon Hanifin and Hungarian-born dermatologist Georg Rajka together published one of the earliest sets of diagnostic criteria for eczema in 1980.
Recent decades have seen the introduction of many new eczema treatments, including corticosteroid Elocon (Mometasone) in 1987, immunosuppressant Protopic (Tacrolimus) in 1990, phosphodiesterase 4 inhibitor Eucrisa (Crisaborole) in 2016, and biologic Dupixent (Dupilumab) in 2017. New treatments for eczema are currently in the development stages, including JAK inhibitors.
Eczema affects approximately 30 percent of the U.S. population. Eczema is more common in children and adolescents. It is associated with seasonal allergies and asthma, together known as the atopic triad.
Common triggers for eczema flares include:
Eczema is not at all contagious. Eczema is not spread by infection, and one person cannot catch it from another.
Many children outgrow eczema. In about 80 percent of children with eczema, symptoms go away within approximately 10 years. In 95 percent of children, eczema symptoms disappear within 20 years. Eczema in adults is usually chronic — treatable, but lifelong.
Eczema is usually diagnosed with a detailed patient and family history, a physical exam, and possibly a skin patch test or other procedures to confirm the diagnosis.
Learn more about how eczema is diagnosed.
Eczema can be difficult to treat. It may be necessary to try multiple treatments before finding one that is effective. Moisturizers, over-the-counter allergy medications, and lifestyle changes may help in milder cases of eczema. Prescribed topical corticosteroids or immunosuppressant medications can help control symptoms by moderating the immune system in the affected areas. In severe cases, it may be necessary to take systemic medications, such as oral corticosteroids, Methotrexate, or Dupixent (Dupilumab) — an injected biologic drug.
Learn more about eczema treatments.
Eczema and psoriasis are separate conditions, although they share some similar symptoms and treatments. Eczema and psoriasis are caused by different types of problems with the immune system. Eczema is more commonly found in babies or young children and, unlike psoriasis, may go away over time. It is uncommon to have both eczema and psoriasis at the same time, but it is possible.
Read more about similarities and differences between eczema and psoriasis.