Scope of the problem

The skin is the body's most visible organ system and its main protection against the environment. It is not surprising that skin complaints account for 4–10% of all emergency department visits annually in the US. Skin disease can represent a wide array of disease processes, from a local dermatologic disease to the manifestation of an underlying systemic illness. The majority of rashes that present to the emergency department (ED) involve infections, irritants, and allergies.

While most of these rashes are benign and self-limited, cutaneous lesions are often the first clinical sign of serious systemic disease. Dermatologic findings can be associated with serious infectious diseases including meningococcemia, gonococcemia, cellulitis, toxic shock syndrome, staphylococcal scalded skin syndrome, disseminated herpetic infections, and Rocky Mountain spotted fever. Other potentially life-threatening skin diseases (Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and urticaria with anaphylaxis) can result from medications. Carcinomas and other inflammatory skin diseases (pustular psoriasis, pemphigus, pemphigoid, and lupus) also have the potential to be life-threatening (Table 30.1).

Anatomic essentials

The skin is divided into three layers. The outer layer is the epidermis, which serves as the outer most protective barrier against the environment. Underneath the epidermis, the vascularized dermis provides support and nutrition for the cells in the epidermis. Other important skin structures are also found in the dermal layer, including nerves, sweat glands, hair follicles, and sebaceous glands. The inner most layer is the subcutaneous tissue.