Signs

Signs are changes in the body that other people can observe or measure, even if you don’t describe them.

• Objective evidence: Signs are “outside proof” of illness—something a doctor, parent, or teacher can notice or record.
• Measured with tools: Many signs come from instruments, like a thermometer (temperature), BP machine (blood pressure), or pulse count (heart rate).
• Seen with eyes: Some signs are visible, such as rash, swelling, redness, or yellowing of eyes (jaundice).
• Why doctors value signs: Because signs can be checked by anyone, they help doctors confirm what might be happening and track whether treatment is working (for example, fever coming down).
• Helpful nuance: A person can have signs even if they don’t feel very sick—like high blood pressure, which may not cause noticeable discomfort but is still an important sign.

Signs act like the body’s “readable clues” that guide diagnosis and care.