The most common source of occupational skin disease is contact dermatitis, an inflammation caused by exposure to an allergen. Whenever possible, the evaluating physician should rely on objective evidence such as lichenification, excoriation, and hyperpigmentation rather than subjective complaints. Patch testing, biopsy, and sensory discrimination tests are reliable tools at the evaluating physician's disposal. Disfigurements of the face are rated using the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, Section 11.3, The Face, and Chapter 8, The Skin, is used for all other skin impairments. The evaluating physician records the history of the injury, evaluates the patient, and, in consultation with Table 8-3, notes any objective clinical studies to diagnose the pathology. The functional history, physical examination findings, and diagnostic test findings values then are assigned using Table 8-2; the functional history acts as the key factor and determines the patient's impairment class, physical examination, and diagnostic test findings, each acting as non-key factors, or modifiers. Finally, the non-key factors are used to modify the impairment rating from its default value within its impairment class, and the result is the final skin impairment rating expressed as whole person impairment. Chapter 8 is used only rarely in impairment rating in workers’ compensation cases, and examiners should study the chapter carefully before using it.