Diseases of the skin and subcutaneous tissue

This chapter includes inflammatory, infectious, autoimmune, and degenerative skin conditions. Examples include dermatitis, eczema, psoriasis, cellulitis, acne, urticaria, and pressure ulcers. The codes often specify severity, anatomical location, and laterality. Chronic inflammatory diseases such as psoriasis and lupus-related skin manifestations are included.
Skin infections may overlap with infectious disease coding, but localized skin involvement is classified here. Pressure ulcers are coded by stage, which is important in hospital quality reporting. Since the skin is the body’s largest organ and a protective barrier, diseases in this chapter can signal systemic illness or result from underlying conditions.