Contact dermatitis and patch testing for the allergist.

OBJECTIVE: To review of contact dermatitis (CD) and its key allergens and provide updates and recommendations for the practicing allergist.

DATA SOURCES: Through the use of various scientific search engines (eg, PubMed and MEDLINE), we reviewed literature on CD, patch tests (PTs), key allergens, occupational dermatitis, and treatment.

STUDY SELECTIONS: Studies on CD, important allergens, and PTs were considered.

RESULTS: Contact-induced dermatitis may be due to allergic CD, irritant CD, systemic CD, contact urticaria, and protein CD. Key allergens include metals (nickel, gold), topical medicaments (topical corticosteroids), and cosmetics and personal care products (fragrances and preservatives such as methyl- and methylchloro-isothiazolinone). Present relevance of a positive PT result is the combination of definite, probable, and possible relevance and should be correlated with the patient's history and physical examination. Treatment of allergic CD includes identification of relevant allergens, patient education, avoidance, and provision of alternative products the patient can use.

CONCLUSION: CD is a common inflammatory skin disease and should be suspected in patients presenting with acute, subacute, or chronic dermatitis. The gold standard for diagnosing allergic CD is a PT. This article provides practical recommendations for the diagnosis and management of CD commonly seen by the allergist in their practice.