Chemical sensitivity and contact sensitivity are forms of dermatitis or skin inflammation that causes rashes, itching, redness and burning sensations. These are caused by contact with a substance that results in an allergic reaction. It can be caused by a chemical, protein or another allergen.
There are a number of triggers for skin sensitivity. Among the most common are pet dander, household items such as scented soaps or fabric softeners, and oils from plants. Other causes of skin sensitivity include hair dyes and straightening solutions, nickel, copper, leather, latex, citrus oil, and even certain lotions and medications. Chemicals and materials in the work environment are also a consideration.
Normally, the first encounter with a substance won’t cause an allergic reaction but it can cause skin sensitivity. Allergies tend to manifest on future contact. This is why people start developing allergies they did not know they had before.
It can sometimes be difficult to determine what causes an allergy. If someone encounters plant contact sensitivity (i.e. poison oak or ivy) the cause is usually fairly obvious. But what happens when the cause is lotion, fabric softener, laundry detergent, pet dander, soap or any other common household contact? It’s important to diagnose the cause of an allergy before it can be treated.
Patch testing is one common and effective way to diagnose skin sensitivity to various substances. In this test, the patient wears a patch containing a given possible allergen for an hour to see if a reaction takes place. Patch testing has also been used for testing (and possible treatment) for certain types of reactions to foods but the technique is not standardized.
Patch testing is one type of skin test to check for allergen sensitivity and localized sensitivity and reactions can be noted over hours or days. The others include a prick test, which provides an immediate reaction (reaction within 10-15 minutes) when the skin is gently pricked with an allergen. The intradermal test is often done when the prick test is negative. In this test, the doctor will inject a tiny amount of the allergen beneath the skin looking for swelling and itching at the site.
Dr. Blessing-Moore and Dr. Maskatia have experience conducting various types of skin sensitivity testing for many patients across the Palo Alto and San Mateo, California areas.