Spidery blood vessels visible on the chest might signal liver disease. Thinning, brittle hair might indicate a thyroid problem. And a beefy red tongue? That could be a symptom of a vitamin deficiency.

Superficial changes to your body — especially if they occur with more-troubling symptoms such as shortness of breath or ankle swelling — can be warning signs of an underlying condition. That’s why doctors can often detect a disorder just by looking, touching and listening. But people often dismiss their symptoms as a normal part of aging and put off going to a doctor until the condition has advanced, missing the chance for early treatment, which can keep many disorders from worsening.

Compounding the problem is that traditional, hands-on exams at the doctor’s office have been largely eclipsed by technological advances. “Too often the physical diagnosis is replaced by a CT scan,” says Robert M. Centor, a professor of general internal medicine at the University of Alabama at Birmingham. Such hit-or-miss testing is costly and can expose patients to unnecessary radiation.

Those realities make it important to be your own periodic self-examiner. The illustration below provides a list of seemingly minor changes that might point to disorders that affect the entire body. If you notice any of them, check with your doctor, especially if you haven’t had a physical recently. And tell him or her immediately if you experience any of these serious changes: swollen feet and ankles, shortness of breath, more nighttime trips to the bathroom, severe unexplained fatigue and difficulty walking or climbing stairs.

One more thing: While slight fluctuations in body weight are common, a significant and unexpected change could signal a serious problem. Unintentional weight loss could be a symptom of cancer, celiac disease, chronic lung disease, Crohn’s disease, depression, diabetes, infection or an overactive thyroid. A substantial weight gain might suggest an underactive thyroid, and a rapid weight increase might indicate fluid retention, a harbinger of possible heart failure or kidney, liver or lung disease.

Call your doctor if:

• You lose more than 5 percent of your normal weight within a year without changing your diet or exercise routine.

• Weight loss is accompanied by fever, pain or changes in bladder function.

• You gain a substantial amount of weight without a known cause.

• Weight gain is accompanied by constipation, hair loss, sensitivity to cold, shortness of breath or swollen feet.

Copyright 2011. Consumers Union of United States Inc.