[2] Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails).

[8][9] Clinically, the diagnosis of any particular skin condition begins by gathering pertinent information of the presenting skin lesion(s), including: location (e.g. arms, head, legs); symptoms (pruritus, pain); duration (acute or chronic); arrangement (solitary, generalized, annular, linear); morphology (macules, papules, vesicles); and color (red, yellow, etc.).

[10] Some diagnoses may also require a skin biopsy which yields histologic information[11][12] that can be correlated with the clinical presentation and any laboratory data.

[15] The skin weighs an average of 4 kg (8.8 lb), covers an area of about 2 m2 (22 sq ft), and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue.

[17] In the embryo, the epidermis, hair, and glands are from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues.

[24] The superficial papillary dermis interdigitates with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone.

[21][25] The function of blood vessels within the dermis is fourfold: to supply nutrition, to regulate temperature, to modulate inflammation, and to participate in wound healing.

The physical examination of the skin and its appendages, as well as the mucous membranes, forms the cornerstone of an accurate diagnosis of cutaneous conditions.

[1] However, with that being stated, the lack of standardization of basic dermatologic terminology has been one of the principal barriers to successful communication among physicians in describing cutaneous findings.