What describes an occupational disease?

An occupational disease refers to a health condition that arises specifically due to the work environment or exposure linked to a particular occupation. In this case, the correct answer is the condition resulting from overexposure to harmful chemicals. This definition aligns perfectly with the concept of occupational diseases, as such conditions are often the result of prolonged exposure to harmful substances present in the workplace, particularly in fields like cosmetology and beauty services where various chemicals are frequently used.

The other choices do not fit the definition of an occupational disease. A mild allergic reaction to hair products pertains more to individual sensitivities rather than a disease directly related to occupational exposure. A genetic condition affecting hair growth is unrelated to occupational factors, as it stems from hereditary factors. Lastly, an illness caused by lack of personal hygiene relates more to personal habits and not to occupational exposure, thereby not typically classified as an occupational disease.