11 Diseases Doctors Are Most Likely to Miss

Updated: Mar. 17, 2022

Some diseases are easy to spot, but others take longer to diagnose. Here's how to get a quicker diagnosis when you have an easy-to-miss condition.

Tricky diseases

Some signs of disease are written all over your face, hands, and even your feet. Other strange signs might not be so obvious—and doctors could miss the disease. Here are the ones that doctors are most likely to miss.

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Lyme disease

Most people have heard of the bulls-eye rash that appears when a Lyme-infected deer tick transmits bacteria, but not every person gets the telltale rash. In those cases, Lyme disease is usually marked by body aches, fever, and fatigue that doctors often write off as the flu, says Albert Ahn, MD, clinical instructor of internal medicine at NYU Langone Health. And it’s easy to see why: The body won’t have time to develop the antibodies that signal the disease until a few weeks after the bite, meaning blood tests won’t reveal it. The symptoms can disappear temporarily, so see if your doctor will give you a one-time antibiotic if you suspect Lyme, suggests Dr. Ahn. “If you miss it and continue to miss it, the long-term effects of Lyme could be debilitating,” he says. Here are 18 more Lyme disease symptoms you should never ignore.

The doctor examines the patient.
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Ovarian cancer

Most women won’t show symptoms of ovarian cancer until later stages, and even then the signs will be vague. One of the most common symptoms is bloating, which could also point to everything from irritable bowel syndrome (IBS) to a bad diet, says Brunilda Nazario, MD, lead medical editor at WebMD. “Would ovarian cancer be on the list? Absolutely, but low on the list,” says Dr. Nazario. If you suspect ovarian cancer, getting genetic testing that reveals a family history can drive a diagnosis quicker, she says. Watch out for these other silent signs of ovarian cancer.

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This autoimmune disease can attack almost every system in your body, showing up as fever, fatigue, facial rash, skin lesions, shortness of breath, dry eyes, and more. “If you meet all the symptoms, that’s an easy diagnosis,” says Dr. Ahn. “Unfortunately, the vast majority of patients do not.” Adding to the confusion for doctors, a patient’s blood tests might appear completely normal. Lupus can also look similar to rheumatoid arthritis, he says. Your doctor might try several treatments before diagnosing lupus; the hope is that you have a condition that is easier to treat or manage. Check out these other 50 secrets hospitals don’t want you to know.

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Fibromyalgia symptoms are so vague that some doctors have questioned its existence even though the Centers for Disease Control and Prevention (CDC) recognizes it. “Classically, they suffer from two things: fatigue and diffuse body pain,” says Dr. Nazario. “Neither one of those things is visible to the eye.” You can’t test levels of exhaustion and pain the way you could, say, a fever, and the two are so vague that doctors need to rule out a laundry list of other diseases before blaming it on fibromyalgia. To speed up the diagnosis, Dr. Nazario recommends coming to your doctor, not just with the symptom (“I’m fatigued”) but how it affects you (“I don’t have the energy to walk my kid to school”).

Young beautiful Caucasian woman on bed having headache / insomnia / migraine / stress


A thyroid that isn’t producing enough hormones can be hard to catch. All of the symptoms—including constipation, dry skin, weight gain, and thinning hair—are too vague to be real red flags, particularly the most common one: fatigue. “In this country, 99 percent of people have fatigue,” says Dr. Nazario. Still, don’t let fear of complaining keep you from reporting your exhaustion to the doctor. It might take some time to pin down the cause, but your symptoms could get worse over time if you don’t catch it. Here are 17 more lies you tell your doctor—and why you should stop.

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With hemochromatosis, your body produces too much iron. It’s a genetic condition that people are born with, yet it rarely shows symptoms before age 50. Often those who find it early stumble upon it randomly, such as when a blood test reveals mild liver inflammation, says Dr. Ahn. Left unchecked, hemochromatosis could lead to heart problems, liver damage, and diabetes. If you know the condition runs in your family, get hereditary testing or have your iron levels checked. If you do have it, there is a treatment: “It’s a little primitive, but it’s almost like blood-letting,” says Dr. Ahn. “You donate blood once a month or every few months, and it’s relatively well controlled.” Don’t miss these other 16 medical tips doctors wish you knew.

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About 1.7 million cases of chlamydia were reported in 2018, but because the sexually transmitted disease usually doesn’t cause symptoms, the actual number of infections could be even higher. Even if you don’t notice a discharge or a burning sensation when you pee, sexually active adults should be screened at least once a year or after having unprotected sex with a new partner, says Dr. Ahn.

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Hepatitis C

Hepatitis C can work its harm silently for years—it can take decades for symptoms to show up, and by that point, it will have caused chronic liver problems. Baby boomers are the most at risk—in part thanks to outdated medical practices when doctors would reuse needles; also, widespread screening of blood donors for the disease didn’t begin until 1992, so anyone who got a blood transfusion before then is at risk. The CDC recommends people born between 1945 and 1965 get tested at least once. While good treatments didn’t exist until the last seven years or so, prospects are much better now. “We have extremely effective, highly successful options that can cure within six weeks of taking the medication,” says Dr. Ahn. Watch out for these other signs your liver is in big trouble.

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Irritable bowel syndrome

This is a tough one to identify—doctors can only diagnose IBS when they can’t find anything else physically wrong with a patient. Doctors first try to rule out other potential causes for the digestive issues—from simple dehydration to the inflammatory bowel disease and autoimmune condition, Crohn’s disease. IBS also can have ever-changing symptoms, from constipation and abdominal pain one day to diarrhea the next—and then disappear completely, says Dr. Nazario. “It takes a bit of a long time to diagnose, and the patient gets frustrated in the process,” she says. Make sure you know these 9 other IBS symptoms.

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Sleep apnea

Some patients write off their snoring as a minor annoyance for their partner, but it could be the sign of something serious: sleep apnea, which can significantly increase the risk of heart disease. Those with the condition don’t just snore—they actually stop breathing numerous times throughout the night, which prevents them from reaching a deep restorative slumber. “They sleep in their bed for six, eight, nine hours a night and wake up and literally feel like they didn’t sleep,” says Dr. Ahn. People who are overweight are at particularly high risk, but if you’re a snorer don’t hesitate to talk to your doctor no matter your size. Here are 13 signs sleep apnea could be hurting you.

Unhappy young woman suffering from pain in the neck
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Heart disease

Heart disease isn’t just a problem for men—it’s also the leading cause of death for women in America. Still, many female patients (and their doctors) don’t recognize the signs of a heart attack, which can look markedly different from the classic chest pressure. Women’s heart attack symptoms can be fatigue, shortness of breath, and discomfort in the neck; if you feel out of sorts and have these signs call 911. Experts aren’t sure exactly what drives the differences, but they do know that heart disease in women looks different than in men: “When they do imaging of heart arteries, in men there tends to be a pretty distinct blockage,” says Dr. Nazario. “In women, it’s more of a diffuse cholesterol buildup.” Don’t miss these other 42 strange symptoms of serious disease.