Dendritic cells are the principal antigen-presenting cells (APCs) in the host defense mechanism. An altered dendritic cell response increases the risk of susceptibility of infections, such as Mycobacterium tuberculosis (M. tb), and the survival of the human immunodeficiency virus (HIV). The altered response of dendritic cells leads to decreased activity of T-helper-1 (Th1), Th2, Regulatory T cells (Tregs), and Th17 cells in tuberculosis (TB) infections due to a diminishment of cytokine release from these APCs, while HIV infection leads to DC maturation, allowing DCs to migrate to lymph nodes and the sub-mucosa where they then transfer HIV to CD4 T cells, although there is controversy around this topic. Increases in the levels of the antioxidant glutathione (GSH) plays a critical role in maintaining dendritic cell redox homeostasis, leading to an adequate immune response with sufficient cytokine release and a subsequent robust immune response. Thus, an understanding of the intricate pathways involved in the dendritic cell response are needed to prevent co-infections and co-morbidities in individuals with TB and HIV.

Limonene is a fragrant terpene commonly found in household and cosmetic products due to its fresh aroma. When exposed to air, limonene autoxidizes to form limonene hydroperoxide, a potent allergen that can cause allergic contact dermatitis. Recently, as the popularity and availability of limonene increased, it has been incorporated into novel products such as flavoring agents for electronic cigarettes or vapes. With the rising acceptance and popularity of marijuana, this usage has extended to cannabis vaping products. Here, we report an unusual presentation of an allergic contact dermatitis reaction to limonene hydroperoxide stemming from cannabis vaping products.