What Is Eczema?

Eczema is an inflammatory disease responsible for the development of a chronic, non-infectious condition of the skin. The most common symptoms are redness and itchiness of the skin, but vesicles (small blisters) can also form. Due to their fragility, vesicles often burst and release stored liquid. The texture of the skin changes to rough: more dry, cracked, and thickened to touch.

Eczema occurs in phases. There are periods when it peaks and becomes severe, and there are periods of decline when the condition presents at a minimal level. In some cases, eczema can temporarily disappear from affected areas.

The areas of affected skin and severity of symptoms are unique to each individual and depend on age. For example, babies with eczema may have affected cheeks, arms, legs, back, stomach area, or chest. Children, teenagers, and adults typically have eczema on the inner part of elbows, back of knees, neck, palms, and soles.

Generally, eczema is triggered by dysregulated immune mechanisms. Patients diagnosed with eczema lack protection from germs in the corneal layer of the skin, as the inflammatory response has damaged that layer. Approximately 30 to 40 percent of patients have an allergic type of eczema, which typically presents as a more complicated case of skin inflammation. In addition to eczema, these patients also have either allergic asthma or hay fever. The immune system responds to allergens through the release of antibodies, which in turn causes inflammation. Some allergens potentially linked with eczema include food products such as eggs, milk, fish, or nuts, as well as pollen and dust. In most cases, however, a single definitive cause for eczema cannot be established. Extreme cold, heat, cigarette smoke, and wool can also trigger the disease.

In certain circumstances, dermatitis (eczema) can be caused by the direct impact of external allergens on the skin, producing what is known as allergic contact dermatitis. Common scenarios include the development of dermatitis as an allergic reaction to metals such as nickel and cobalt, baby wipes containing methylisothiazolinone, hair colour products containing paraphenylenediamine, and many others. In these circumstances, a specific diagnostic test called a patch test is used. The patch test is distinct from the skin prick test used in allergy clinics, which is primarily indicated for the diagnosis of hives and is not particularly helpful in diagnosing allergic dermatitis.

Eczema (dermatitis) is diagnosed by a dermatologist through a physical examination. If an allergic reaction is suspected, a patch test may be assigned to determine further causes.

Since eczema is a chronic disease, it cannot be completely cured; however, it can be properly managed. The symptoms of itchiness, redness, and dryness can be regulated through a careful skin care routine and prescribed medications. Steroid creams may be prescribed to reduce skin inflammation and itchiness. In addition to topical steroids, other classes of medications are widely used, including topical calcineurin inhibitors (tacrolimus, pimecrolimus) and the phosphodiesterase-4 inhibitor crisaborole. Specialised soaps, cleansers, shower gels, and shampoos can also assist in maintaining skin regulation. It is recommended that moisturisers be applied at least twice daily to prevent excessive drying and irritation. The recommended list of products and options is typically discussed with patients during follow-up appointments.

In addition to topical products, ultraviolet (UV) light therapy can be incorporated as part of treatment. UV light helps to block the immune mechanisms that are dysregulated and cause inflammation. The Centre for Medical and Surgical Dermatology offers phototherapy for the treatment of eczema.

Systemic medications can be used as an alternative treatment method to topical treatments and phototherapy when eczema is severe. In medical dermatology, pills and injections are considered types of systemic medications. Antibiotics, mycophenolate mofetil, oral or injectable corticosteroids, azathioprine, and small-molecule immunosuppressants such as methotrexate and ciclosporin are examples of systemic medications that may be prescribed by a dermatologist to manage severe eczema. Additionally, the biologic medication dupilumab is approved for the treatment of severe eczema.

Systemic treatment for eczema should be prescribed only by a board-certified dermatologist experienced in managing complex skin conditions. A board-certified dermatologist can be found through the Find a Dermatologist service of the Canadian Dermatology Association.