The different definitions of skin disease in medicine and in law are frequently confusing for dermatologists. While a skin disease may be defined medically referring to the definition of health by the WHO as a pathological condition of the skin leading to a disruption of the physical, mental and social well-being of the individual, legal definitions vary depending on the field of insurance law that is referred to. In the law of private health insurance, a skin disease is defined as an anomalous condition of the skin requiring medical treatment that exists independently of the subjective judgement of the insured person and needs to be objectively confirmed by a medical evaluation. In contrast, in the law of the social health insurance, the Federal Court of Social Justice defines disease as irregular physical or mental condition, deviating from the perception of a healthy human being that requires medical treatment or leads to inability to work. Substantial bodily disfigurement may be regarded as an irregular physical condition. In the law of the statutory accident insurance, occupational skin diseases are defined under clause 5101 of the occupational disease regulation as serious or repeatedly relapsing skin diseases that have forced a person to refrain from any work activities causal for the development, the aggravation or the recurrence of the disease. The Federal Court of Social Justice interprets the term "skin disease" from the protective purpose of the law, i.e. the protection against the economic and health consequences of the exposure to harmful agents and a thereby forced change of profession. This broad interpretation of the term "skin disease" leads to the recognition of diseases of the conjunctiva of the eye or diseases of the blood vessels of the skin due to cold damage as skin diseases according to clause 5101. For the correct treatment and possibly notification of occupational skin diseases in collaboration with various insurance carriers, dermatologists should be familiar not only with the medical definition, but also with these different legal definitions of skin disease.