IgE Testing May Be Underused in Dermatology

Allergists have long used immunoglobulin E quantitative assaying of allergens (IgEQAA) to determine reactivates for allergies associated with a runny nose and asthma. However, the test is not widely used for other dermatologic conditions. Now, new research shows the test may be useful in identifying antigens associated with atopic dermatitis (AD). Test results can help patients avoid sources of some specific environmental allergens and lessen disease severity, according to a study published June 20 in the International Journal of Dermatology.

The researchers retrospectively assessed affected AD severity based on body surface area (BSA) at first presentation, IgEQAA classes, and total IgE concentration (Immunocap; Thermo Scientific) for 54 patients (average age of 42.9 years) with AD, seen in a private dermatology practice. The panel included the most common respiratory allergen antigens.

The researchers found that 41 of the 54 patients had an abnormally high total IgE concentration (defined as greater than 150 IU/ml) with an average IgE concentration of 2682.7 IU/ml. Additionally, nine patients (17 percent) had significant improvements in AD symptoms after making lifestyle changes to avoid allergens (such as dog, cat, Bermuda grass, and rabbit) that patients had been in contact with. No patients had repeat IgEQAA levels drawn, as results would not be expected to be significantly different from pre-lifestyle change levels.

"From our data it appears that IgEQAA testing can have a significant impact on treatment outcomes in selected patients with AD," writes senior author Douglas Johnson, M.D., from University of Hawaii. "IgEQAA is easy to perform, compared to skin prick testing, and may be helpful in some patients who are not responding to conservative treatment."

Yet, Johnson tells DTET, IgE testing is not routinely ordered as part of AD care.

"I think that ordering the test and sharing the results with the patient and family can play a significant role in some patients," Johnson says. " It saved them from immunosuppressive therapy, biologics, topical treatments and phototherapy."

Yet, Johnson cautions that some aeroallergens, such as dust mites, may be unavoidable.

Takeaway: IgE testing may enhance care for AD by identifying avoidable allergens associated with worsening disease severity.