The skin is a dynamic organ that contains different cells which develops several biosynthetic and immunological processes as the innate and adaptive immune responses activated when the tissue is under attack. The immune adaptive response is induced by dendritic cells (Langherhans cells) presented in epidermis; they are responsible to capture, process and present the antigen to T lymphocytes in local lymphoid organ. As result, T lymphocyte express CLA molecule, that is a selectin-E ligand presented in the endothelium, the lymphocyte moves to the epidermis and resides as a T memory cell, thus activated to inflammatory responses once dendritic cell presents the antigen. The dysregulation of these mechanisms is associated with inflammatory skin diseases as allergy, infection, or cancer. Therefore, the knowledge of these immunologic mechanisms will allow proposing therapeutic strategies to modulate these entities.