This course covers skin microbiota and immune components of the skin in healthy and disordered states. The microbiology will cover bacterial species that cause the most common skin infections, such as Staphylococcus aureus (folliculitis, impetigo, abscesses, pyoderma, toxic-shock syndrome, staphylococcal scalded skin syndrome, wound infections); Streptococcus pyogenes (impetigo, erysipelas, cellulitis, necrotizing fasciitis, rheumatic fever, scarlet fever, wound infections), and Corynebacterium spp. (wound infections), etc. The bacterial biofilms and their importance in skin infections will also be addressed. The skin hosts the same immunocompetent cell types found throughout the body -T cells, B cells, macrophages, eosinophils, neutrophils, etc., and its skin-specific subpopulations--Langerhans cells, keratinocytes, and dermal dendrocytes. The second part of the course will cover the biology of immunology of the skin in normal functioning and underlying both intradermal allergic reactions and skin-specific autoimmune disorders ( alopecia areata, vitiligo, psoriasis), as well as the standard treatments for each. Further, this course addresses unique immune environments within the skin, such as the immune privilege of the hair follicle and wound infection.