Medically, a symptom refers to a subjective characteristic of a disease, while a sign is an objective indicator of a disease, according to Medical News Today. However, many lay people mistake the two terms as being synonymous.
The symptoms of a disease are subjective in the sense that it's only the patient who notices them, and they include sensations such as pain and fatigue, as Medical News Today explains. By contrast, signs are objective because they're noticeable by other people, including doctors, nurses and relatives. Examples of medical signs include bloody stool, skin rashes and elevated blood glucose.
The symptoms of a disease can mainly be categorized into three types, as MedicalNewsToday reports. The types include chronic, relapsing and remitting symptoms. While chronic symptoms last longer and result from chronic conditions such as diabetes and asthma, relapsing symptoms usually heal temporarily and return after some time, such as in the case of conditions such as depression. As for remitting symptoms, they usually get better and may disappear permanently.
The types of medical signs include prognostic, diagnostic and anamnestic signs, according to Medical News Today. Prognostic signs project the end point of a medical condition, such as death. For instance, medical signs such as sunken eyes and discolored complexion may signify impending death. While prognostic signs reveal the disease that a person suffers from, anamnestic signs indicate a past medical condition.