A Hands-on Approach to Contact Dermatitis and Patch Testing.

Contact dermatitis (CD) is a common skin condition caused by contact with an exogenous agent that elicits an inflammatory response. Although history and physical examination can be helpful in distinguishing between irritant CD and allergic CD (ACD), the gold standard for diagnosing ACD is patch testing. Although the actual patch test (PT) procedure and application is relatively straightforward, the decisions involving which allergens to use, interpretation of results, determination of relevant allergens, and subsequent patient management require more skill and expertise. Often, the distribution of the presenting dermatitis can provide insight into the potential causative allergens and should be taken into account when selecting PT allergens. Commercially available PT panels and personal care products can be used for patch testing. Determining the clinical relevance of PT results is a critical component of the PT procedure. Patients must be educated on avoidance of relevant allergens and given guidance on alternative products available for use. Special populations, including children with ACD and occupational CD, and patients with biomedical devices have unique allergen considerations, and PT panels should be directed as such to address all potential allergens.