Eczema

Causes

What causes eczema?

While it’s not entirely understood what causes eczema, there seems to be a complex interplay between genetic, immunologic, and environmental factors.

Let’s start with some background: The outermost layer of your skin is called the epidermis, and it acts as a physical barrier against environmental insults and water loss. In eczema, there are two primary problems. First, there is a genetic “barrier defect” (eg, a compromised, less-protective epidermis). Second, the skin’s own immune system responds excessively to environmental allergens and irritants.

The barrier problem results in small breaks in the skin, allowing irritants to permeate, and causing excessive dryness from loss of moisture. This leads to itchiness and the urge to scratch. Scratching triggers the hyperreactive immune response, which in turn causes more itching, leading to a vicious cycle that provokes the characteristic skin lesions (rash) we see in eczema.

Is eczema linked to any other diseases?

People with eczema are more likely to also have asthma and environmental allergies (allergic rhinitis), and often have a family history of these conditions as well.

Can eczema be caused by food allergies?

Rarely, eczema flares may be related to a food sensitivity, but in the great majority of cases, no meaningful food allergy or trigger exists. Testing for food and environmental allergies is not recommended.

Which environmental factors commonly trigger eczema?

People with eczema tend to be sensitive to a variety of environmental triggers. Avoid bubble baths, fabric softener sheets, harsh soaps, and detergents. Wool and other types of scratchy clothing are other common triggers. Exposure to cigarette smoke should also be avoided.

In some people, dryness and itchiness may be worse in the winter months when the humidity is low. Others are easily irritated by sweat, and struggle more during the summer months.

Try to keep the temperature and humidity in your home fairly constant. A vaporizer or humidifier in the bedroom can be helpful in the winter. An air conditioning unit may be necessary in the summer. When using these devices, it’s important to clean them well and frequently, as they can be sources of mold, which can also irritate the skin.

Is eczema contagious?

No, it’s not. While the exact cause is unknown, it’s thought to be an interplay between genes and environmental triggers.

Symptoms

What are the signs and symptoms of eczema?

People with eczema have dry, itchy skin. Their skin may also feel or look raw or scaly, and scratching it causes a rash to appear.

People of different ages can show different patterns of rash. In infants, the face is commonly affected, though the rash may also cover a large part of the body. In children, the rash often localizes to the legs, feet, hands, or arms. In older children, the bends of the elbows and knees are common sites of eczema.

Adults often show similar rash patterns to older children. The creases of the elbows and knees may be affected, while the face, neck, or hands are other common locations for outbreaks. The distribution of the rash can be highly variable between people.

Can you “grow out of” eczema?

While it is possible for the disease severity to wane as you age, many dermatologists feel that no one truly grows out of eczema—it just evolves as we age and may show up in a very localized fashion in adulthood (for example, dermatitis of the hands).

Can eczema cause more serious problems or complications?

Especially if there is a lot of scratching, the rash may become infected with bacteria, yeast, or viruses that exist on the skin. This is known as “secondary infection”—with bacterial secondary infection being the most common. The rash becomes very red and may have pus-filled pimples and scabs. A topical or oral antibiotic prescribed by your clinician may be needed to help the infection resolve.

Diagnosis

How is eczema diagnosed?

Eczema is a clinical diagnosis, meaning it is diagnosed on the basis of a medical history and physical examination. Sometimes multiple visits or exams are needed to confirm the diagnosis. Lab testing and skin biopsy are not used routinely.

Prevention and Treatment

How is eczema managed?  

While there is no cure for eczema, it can be controlled with a diligent multifaceted treatment approach. The three goals are to restore the compromised skin barrier, decrease dryness, and control inflammation. Accordingly, the cornerstones of treatment are skin care (skin hydration), trigger management, and medication (primarily in the form of topical treatments). With a clear and committed treatment plan, flare-ups can often be prevented or significantly attenuated.

How should people with eczema care for their skin?

Moisturizers (sometimes called emollients) are the primary therapy for eczema because they help rebuild and repair the defective skin barrier. Consistent use of moisturizers results in less itching, less severe disease, and less need to use medicated creams.

Frequent application of moisturizers, depending on how much of the body is affected by eczema, can be time-intensive. But it yields great rewards in terms of keeping flare-ups and overall disease progression at bay. An appropriate skin care regimen should be used by all who have eczema, regardless of disease severity.

How do I choose a good moisturizer for my eczema-prone skin?  

In general, people with eczema should look for moisturizers with greater oil than water content. The words that are used to label moisturizers are actually quite important to pay attention to. Ointments are more potent than creams, and creams are more potent than lotions.

For regular use, in times when the eczema is not flaring, creams are often a good starting point. In especially dry or flare-prone spots, an ointment may be helpful. The downside of ointments is their thicker consistency. They can be harder to spread over large areas, and may look or feel greasy. Consider a heavier product at night and a lighter one during the day. Ultimately, the “best” moisturizer is the one you will actually use, and use consistently!

In addition, look for products that are fragrance-free (or low fragrance). Fragrance can be very irritating to skin with eczema. Note that “baby” products often contain harsh chemicals and fragrances.

Protective ingredients that are helpful in rebuilding the skin barrier include petrolatum, dimethicone, glycerin, colloidal oatmeal, and ceramides. Products marketed as “barrier repair creams” often contain ceramides and/or dimethicone, and can be quite helpful.

Moisturizers should be applied at least twice daily, and immediately after bathing or washing hands.

Can people with eczema bathe normally?

Regular bathing or showering is important to hydrate and clean the skin. Be aware that all soaps are drying and should be used sparingly, only on areas that really need it. It’s best to use mild or gentle soap, or soap-free cleansers—ones that contain moisturizers and don’t leave the skin feeling “squeaky clean” (a sign that the skin has been stripped of all its good oils and is too dry). Again, look for fragrance-free or low fragrance. After bathing, pat dry (don’t rub), and apply moisturizer immediately while the skin is still a bit damp. This is known as the “soak and seal” method.

Which medications are used to treat eczema?

Most commonly, topical treatments are employed to treat eczema. Topical steroids (eg, hydrocortisone, triamcinolone, clobetasol) and topical calcineurin inhibitors (tacrolimus, pimecrolimus) are the two most commonly used medication classes. Your clinician will tailor a treatment plan that is appropriate for the location and severity of your eczema.

Topical corticosteroids (steroids) work by decreasing skin inflammation and are the most commonly used medications during eczema flare-ups. Studies show they are generally safe, though long-term daily use can lead to thinning and discoloration of the skin, especially when used on delicate areas. This is known as cutaneous atrophy, and it can be permanent.

To lower the risk of atrophy, strong steroids are avoided in sensitive regions such as the face and skin folds (eg, underarms, groin, and the bends of the elbows and knees). Additionally, the duration of daily use is typically limited to a few weeks. It’s very rare to see systemic (whole-body) side effects from topical steroids. Other skin side effects can include stinging or burning, though this typically improves after several applications.

Topical calcineurin inhibitors (TCIs) are the other class of medications commonly used in the treatment of eczema—in place of, or in addition to topical steroids. Like steroids, they reduce inflammation and itching. Importantly, they can be safely used on thin or sensitive areas of the skin because they do not lead to skin thinning. Their most common side effect is burning, itching, or stinging. As with topical steroids, this will typically improve after a few days of use.

TCIs carry an FDA black box warning regarding a possible association with the development of malignancies (cancers). However, there is no firm evidence of this link, and most dermatologists feel the black box warning is unwarranted. In controlled trials, TCIs appear to be safe in adults and children.

How should topical treatments be applied?

Whenever using a prescription topical treatment (either topical steroid or TCI), you should first apply the medication to the affected area, and then apply a layer of your preferred moisturizer on top. This provides a “seal” that locks in the treatment.

When the area is clear, you can stop or taper the use of the prescription. The time needed to clear a flare is typically 2 weeks or less with topical steroids. To prevent future flares, two strategies can be employed. The first is to continue at least twice-daily use of your moisturizer.   The second involves using one of the prescription topical treatments discussed above approximately twice weekly – in addition to twice-daily use of your preferred moisturizer. Talk with your clinician about which option might be best for you.

If the usual therapies are not helping, what other treatment options exist?

UV phototherapy (light treatment) is considered second-line therapy for moderate-to-severe eczema. It reduces skin inflammation with minimal side effects.

There are also a few options for systemic (oral or injectable) therapy that can be considered for severe eczema under the care of a dermatologist. These options typically suppress the immune system and have less favorable side effect profiles. Dupilumab (Dupixent) is a newer option in the “biologic” category, which works by altering the inflammatory cascade that leads to eczema.

Are there any effective integrative treatments for eczema?

Currently, there is no conclusive evidence to support integrative treatments for eczema, but oral evening primrose oil, oral borage oil, probiotics, and topical St. John’s wort have demonstrated benefit in some small studies. Consider an anti-inflammatory diet, with adequate intake of omega-3 fatty acids such as those found in fish, walnuts, and flaxseed.  This type of diet can have benefits in many other conditions as well.

Useful Links

A comprehensive eczema resource center (American Academy of Dermatology)

A more clinical look at eczema (American Family Physician)

Website devoted to resources and education (National Eczema Association)

A patient education resource (UpToDate)

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