Taking the Itch Off

Contact dermatitis allergens and treatments

/ Author:  / Reviewed by: Robert Carlson, M.D

Itching, bumpy, burning skin? Looking at your arm wondering, "Well where did this come from?" Irritation of the skin, or contact dermatitis, can be caused by either irritants or allergens.

Knowing what type of irritation is occurring, how to treat it and what the leading causes are can help you cope with these skin issues.

Allergen or Irritant?

According to PubMed Health from the US National Library of Medicine, contact dermatitis occurs when an area on the skin becomes red, sore or inflamed after coming into direct contact with a substance - either an allergen or an irritant.

Common irritants are products like soaps, detergents or chemicals like acids or pesticides. When irritant dermatitis is at play, the affected area often resembles and feels like a burn.

Red and rough, painful skin can also form in response to an irritant, commonly on the hands, face or neck, depending on the source.

Allergens vary from person to person, and are caused when one becomes extra sensitive to a particular substance. Poison ivy is an example of a material people are commonly allergic to. For many, exposure to this plant will result in allergic contact dermatitis.

This type of dermatitis can itch severely and appear as a patchy, red rash that may not show up until one to two days after exposure.

PubMed Health reports that allergic dermatitis may also feel warm and tender, develop red bumps and blisters, become scaly or raw, or crust and drain.


When dealing with irritant dermatitis, the first step is to wash the area thoroughly and ensure that all traces of the substance to blame are removed.

"In some cases, the best treatment is to do nothing to the area," and simply give it time to heal, reports PubMed Health.

In some cases, moisturizers can assist with healing and combat dryness, and can help prevent the contact dermatitis from reappearing.

A doctor may provide prescription creams to treat the skin, or over-the-counter corticosteroid ointments may help ease inflammation. Instructions should be carefully followed when using either.

Doctors may also prescribe coricosteriod pills or shots in severe cases, though this is less common.

According to PubMed Health, the condition usually heals in a few weeks, unless the allergen or irritant is either unknown or unavoidable.

Top Allergens

A Mayo Clinic study led by Mark D. P. Davis, MD, and published in the Archives of Dermatology in 2008 examined the top sources of allergic contact dermatitis.

Researchers utilized patch testing for this study, a method of analyzing sources of contact dermatitis.

In patch testing, common allergens are placed on patients' skin and covered with patches. After two days, the skin is examined to see if irritation has occurred, and if so, from what sources.

This study looked at contact dermatitis testing results from 3,854 Mayo Clinic patients in Minnesota, Florida and Arizona over five years (from January 2001 through December 2005). An average of 69 different allergens were tested on these patients.

Results showed that 2,663 (or 69.1 percent) had at least one reaction, and 1,933 patients (50.2 percent) had two or more reactions.

The top three most common allergens were nickel, gold and Balsam of Peru.

Nickel is a metal often found in jewelry or in buttons on clothing. Gold is also most commonly encountered as an allergen when worn as jewelry. Balsam of Peru is a fragrance that is often used in lotions and perfumes.

Rounding out the top five most common contact dermatitis allergens were thimerosal, a material derived from mercury and found in antiseptics and vaccines, and neomycin sulfate, an antibiotic most commonly found in creams and ointments for first aid.

The authors noted that some regional differences between the three Mayo Clinic locations were seen, saying, "patch testing with the same allergens can show different reaction rates in different parts of the United States."  One possibility behind this difference is variations in regional occupations.

Another study by Dr. Davis, published in the Journal of the American Academy of Dermatology in 2007 explored how well patients recall the results of their contact dermatitis patch tests.

Researchers mailed surveys to 1,453 Mayo Clinic patients who had undergone patch testing. Of these, 757 surveys were returned, 580 of whom had positive reactions. (Sixty-eight percent of those who responded were women.)

Responses were recorded an average of 13.4 months after the patch testing occurred.

Patients were asked to write in the allergens they tested positive for. Of 2,547 total positive allergen results, only 1,229 (48.3 percent) were recalled.

Individual patients only remembered, on average, 51 percent of their positive allergen results. However, 198 people (34.1 percent) did remember all of their allergens.

According to the authors, "Although patients reported both satisfaction with patch testing and improvement in skin conditions, they forgot more than 40% of identified allergens. Techniques are needed to improve patient recall."

Education on the part of both doctors and patients may help improve these rates. Remembering specific allergens will help patients heal from contact dermatitis and prevent future cases.

When experiencing symptoms of contact dermatitis, a visit to the doctor can help determine the allergen or irritant behind the discomfort, as well as the best method of treatment.

Review Date: 
August 28, 2012