Symptoms are your body’s way of telling you that something is wrong. For example, if you have an earache or a stomach ache, your doctor will ask you about your symptoms to help figure out what’s wrong. The more details you give your provider, the better. That’s why it’s important to share any symptoms, even if you think they are not serious.
Signs are outward signs that can be observed by someone other than the person experiencing them (such as a rash or a swollen ankle). They also show up on medical tests.
For example, a person who has cancer might have lymph nodes (part of the immune system that helps trap harmful substances) near the neck and under the arms. When cancer cells are trapped there, the nodes can swell and feel like a lump under the skin.
On the other hand, a person who has dementia may start misplacing things or forgetting where they put their keys. These are common symptoms of Alzheimer’s disease.
The two terms “sign” and “symptom” are sometimes used interchangeably, but the difference is important. A symptom is subjective and can only be noticed by the person experiencing it, while a sign is objective and can be seen by physicians or nurses. The difference is important because a disease can exist without any signs or symptoms, and a person can be asymptomatic for years until the disease causes severe damage, internal inflammation, or other complications. For example, high blood pressure can be asymptomatic until it damages multiple organs.