Contact dermatitis, a common disease, is caused by repeated skin contact with contact allergens or irritants, causing allergic contact dermatitis (ACD) and/or irritant contact dermatitis. Investigators are trying to identify biomarkers to distinguish irritant and allergic patch test reactions, which could aid diagnosis. They have also recognized some promising candidates recently, yet their verification and validation in clinical cases are pending. 

Researchers are constantly describing new causes of ACD. In a recent review, Johansen et al have described 10 new contact allergens from recent years, among which several are related to anti-aging products. Considering this, the European Union has regulated frequent allergens that have caused considerable morbidity in the population, such as the preservative methylisothiazolinone, following which they have observed a significant drop in the number of cases. However, these rates remain still high in other areas such as North America. Other frequent causes for concern are fragrance allergens, especially the widely used terpenes and acrylates encountered in medical devices for the control of diabetes. These represent unsolved issues. 

Recent advances in immunology have given a better understanding of the complexity of contact dermatitis, especially ACD, which has been more heterogenous than previously understood, with several subtypes. There is considerable potential for developing new drugs to treat contact dermatitis with the rapid advancement of molecular understanding of ACD.

Source: Johansen JD, Bonefeld CM, Schwensen JFB, et al. Novel insights into contact dermatitis. J Allergy Clin Immunol. 2022;149(4):1162-71.