Skin

On Contact Dermatitis, Sensitive Skin, and Patch Testing: Interview with an Expert

Is a rash a skin allergy or an irritation? What is a patch test and why would I need one? How can I prevent rashes? To get clarity, we spoke to Jenny Murase, Chair of the CAMP Optimization Task Force of the American Contact Dermatitis Society, Associate Clinical Professor at UCSF, and Director of the Patch Test Clinic at the Palo Alto Foundation Medical Group.

1) We understand that the American Contact Dermatitis Society is an organization for dermatologists who are interested in or specialize in contact dermatitis. Why is the ACDS necessary?

The ACDS provides a critical role in the dermatology and allergy community. Our society is a group of subspecialists who provide diagnostic testing for dermatitis (rash). When someone gets a rash that is chronic (lasts a long time) and recalcitrant (does not respond to therapy), it is possible that there is an external component to consider. Irritant contact dermatitis and allergic contact dermatitis are both possible. Through our patch testing, we help to uncover what could be triggers for rash. The ACDS provides dermatologists and allergists with tools to educate their patients during this testing, such as handouts describing the patient’s allergens and the Contact Allergen Management Program (CAMP) which creates a safe list of products for patients that do not contain their allergens.

2) What are some common allergens?

These include some substances in skin care products like some preservatives, fragrances, surfactants, and emulsifiers as well as hair dyes, textile dyes, metals, topical medications like antibiotic ointments or topical steroid ointments, plastics, rubbers, adhesives, among many other allergens.

3) What is a patch test and why is it useful?

Patch testing is a diagnostic test that looks for delayed hypersensitivity reactions, which means rashes on the skin that develop in response to an allergen coming in contact with the skin that the patient has developed memory immune cells to recognize and respond to. A classic example would be poison oak, where a patient is exposed and then develops a red rash within days because they have immune cells that respond to the poison oak allergen. This is different from an immediate hypersensitivity reaction mediated by histamine which results in an immediate reaction on the skin, like contact hives (urticaria) or an anaphylaxis reaction (like latex allergy, for example). Because this is a delayed reaction, it takes a few days to read the test. Patches with certain substances are placed on the back and are removed after 48 hours, with an interpretation at 3-7 days after placement to see how the patient is responding to the allergens.

4) What are some of the causes of skin allergies and what are some best practices to manage them?

I listed the causes of skin allergies in my answer for question two, and the best practice is avoidance of the allergen, if at all possible. We provide patients with a safe product list through CAMP for skin care products ranging from shampoos, soaps, moisturizers, and even laundry soap and detergents. We also provide ways to avoid non-skin care product allergens like rubber in certain rubber gloves or textile dye allergy through dye-free clothing. In addition, we provide dietary tips on how to avoid consuming some allergens that can cause a “systemic contact dermatitis,” including allergens like tocopherol, propylene glycol, balsam of peru, cobalt and nickel.

5) Is sensitive skin common or is it all hype/a trendy excuse?

Sensitive skin can mean a variety of things to patients. Someone who has had hives (urticaria) or eczema (atopic dermatitis) can feel that they have sensitive skin since their skin breaks out in rashes easily. It can also mean that they have become more and more sensitive to skin care products throughout their life by developing allergic contact dermatitis slowly over time. Diagnostic testing like patch testing can help to clarify what is driving the rash and/or the itch.

6) What is CAMP, why was it created, and how does it help patients who’ve had a patch test?

CAMP is the Contact Allergen Management Program. It was created for ACDS members in order to be able to provide a safe list of products that do not contain the allergens that the patient is allergic to or any of the cross reactants. It can be difficult to read labels if you do not know all the different chemical names and cross reactors. For example, if you tested positive to formaldehyde, you needs to avoid ingredients like Quaternium 15 and DMDM Hydantoin. CAMP takes the guess work out of finding safe products for the patient because it is easier for them to look for items on their safe list and buy those than to try to process all the possible reactions.

7) We heard there’s a new app for CAMP! Is it for me (does my dermatologist have to be a member of the ACDS), and how can I check?

In order to get access to the CAMP app, your dermatologist needs to be a member of the ACDS. CAMP will generate codes that you place into the app when it is downloaded to the phone, and using these codes, a list of products that do not contain your allergens can be generated.
Find an ACDS-member provider in your area that does patch test on the ACDS website.
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