You Could Have One of These Terrible Diseases Without Even Knowing It

We’ve all been there; your throat feels scratchy and your temperature is high. It may be easy to spot the flu, but not every disease is easy to detect. The following conditions could wreak havoc on your body. We’ve ranked them from most to least common so you’ll know what to look for. One deadly cancer can go undetected for years (page 15).

17. Chronic kidney disease

doctor writing on a medical chart.

Doctors often miss this chronic illness. | Bojan89/iStock/Getty Images

  • Affects: 30 million Americans
  • Symptoms: headaches, appetite loss, itchy skin, muscle cramps, swelling of hands and feet
  • Misdiagnosed as: malnutrition

Our kidneys keep our bodies chemically balanced. But when they’re damaged, waste gathers in the bloodstream. The majority of those with CKD don’t know they have it. If left untreated, it can lead to kidney failure, heart attack, or stroke, according to WebMD.

Next: You don’t want issues with this kind of sugar.

16. Type 2 diabetes

Man checking his blood sugar levels

You can have diabetes and not even know. | iStock.com

  • Affects: about 29 million Americans
  • Symptoms: feeling thirsty, tired, or hungry
  • Misdiagnosed as: type 1 diabetes, chronic fatigue

You can be born with type 1 diabetes, but developing type 2 happens as you age. The American Diabetes Association explains the condition causes blood glucose levels to rise because your body fails to use insulin, which helps regulate blood sugar. Unfortunately, people feel hungry, thirsty, or tired for many reasons, so it’s hard to detect type 2 diabetes.

Next: Your snoring may indicate bigger issues.

15. Sleep apnea

Portrait of a man sleeping soundly in his bedroom.

Sleeping man | Minerva Studio/iStock/Getty Images

  • Affects: 22 million Americans
  • Symptoms: heavy snoring, fatigue, tiredness, and poor concentration
  • Misdiagnosed as: insomnia or a psychiatric disorder

About 90% of people with sleep apnea aren’t diagnosed. Doctors don’t learn a lot about the condition in medical school, according to CBS News, so they can overlook it. Denying it may seem fine, but sleep apnea is linked to increased chances of heart attack and stroke.

Next: Things literally break down for older adults.

14. Osteoporosis

Man holding his knee in pain

This disease literally means “porous bones.” | iStock.com

  • Affects: 10 million Americans
  • Symptoms: No clear signs or symptoms exist.
  • Often goes undetected.

Bone density loss leads to weak bones, aka osteoporosis. The National Osteoporosis Foundation says the disease is responsible for over 2 million broken bones per year. Some people even lose height if it affects their vertebrae. Still, it can take years for those with osteoporosis to notice.

Next: Doctors can overlook this mental illness for years.

13. Bipolar disease

Man and wife arguing with hand on hip

This mental illness can masquerade as many issues in adulthood. | IT Stock Free/iStock/Getty Images

  • Affects: approximately 5.7 million Americans
  • Symptoms: intensely elevated moods and feelings of grandiosity
  • Misdiagnosed as: depression, ADHD, panic disorder, obssessive compulsive disorder

Doctors often misdiagnose bipolar disease as attention deficit-hyperactivity disorder in children. Regardless, it’s often not identified until adulthood. University of Pittsburgh Professor of Psychiatry, Dr. David A. Axelson, told CBS, “The best tip-off is that mania of bipolar illness is episodic, whereas the behavior is chronic in ADHD.” If you’re concerned, consult a mental health professional.

Next: Doctors can’t diagnose this condition with lab tests.

12. Fibromyalgia

Man in pain

Widespread pain can make life miserable. | Source: iStock

  • Affects: about 5 million Americans
  • Symptoms: depression, anxiety, intense fatigue, increased sensitivity to pain
  • Misdiagnosed as: chronic fatigue syndrome, rheumatoid arthritis

This condition impacts the way your brain processes pain by increasing unpleasant sensations. No diagnostic lab tests exist, explains the AARP, but doctors can diagnose fibromyalgia when someone reports at least 11 painful areas of the body as well as a history of widespread pain.

Next: You may not think it’s possible to contract this disease.

11. Hepatitis C

Woman talking to doctor about her symptoms

Hepatitis C can cause a range of problems with the liver. | iStock.com

  • Affects: 3.5 million Americans
  • Symptoms: abdominal pain, yellow eyes, gastrointestinal bleeding, nausea, fatigue
  • Misdiagnosed as: depression, heart problems, arthritis, or ulcers

A virus that attacks your liver, the WHO says hepatitis C is often spread through injection equipment for drug usage, but it can also occur through sexual contact. While the acute infection can clear itself within six months, it can become chronic and lead to liver damage. There’s about a two-week window from when you contract the disease to when symptoms show. However, about 80% of cases don’t exhibit symptoms.

Next: The second leading cause of blindness in the U.S.

10. Glaucoma

Close up of a woman's eye

Glaucoma affects the eyes and can cause blindness. | iStock.com/Jean-Philippe Wallet

  • Affects: 3 million Americans
  • Symptom: pressure behind the eyes
  • Misdiagnosed as: optic neuritis, papilledema, or toxic amblyopia

The second leading cause of blindness in the U.S., glaucoma comes with few to no symptoms. Eye disorders linked with glaucoma harm the optic nerve, which sends information from the eye to the brain, explains All About Vision. When the disease advances, you can experience peripheral vision loss or total blindness.

Next: How much do you love carbs?

9. Celiac disease

Man holding his head while laying down

Celiac disease often comes with no symptoms. | iStock.com

  • Affects: 3 million Americans
  • Symptoms: fatigue, joint pain, depression, migraines, and iron or vitamin deficiency
  • Misdiagnosed as: food intolerance, irritable bowel syndrome, or Crohn’s disease

Although tons of people profess to be gluten-free, many people with celiac disease don’t know they have it. This autoimmune disorder damages the small intestine when you eat gluten, a protein found in rye, wheat, or barley, according to the Celiac Disease Foundation. While it may seem like you’d notice if gluten doesn’t agree with you, more than 200 symptoms exist, and no two cases look alike.

Next: Get tested no matter your age or lifestyle.

8. Chlamydia

Woman upset about her diagnosis

Chlamydia is one of the most common STDs in the U.S. | iStock.com

  • Affects: 1.6 million Americans
  • Symptoms: genital pain, abnormal discharge, vaginal bleeding
  • Misdiagnosed as: urinary tract infection

Many people who have chlamydia don’t know due to its lack of symptoms. The infection can damage a woman’s fallopian tubes, leading to infertility or an ectopic pregnancy, says MedicineNet. Chlamydia can live in the cervix, urethra, rectum, or throat, and it can pass from mother to child during birth.

Next: This disease can trick your body for years.

7. Lupus

Doctor and patient

Be your own health advocate. | Gpointstudio/iStock/Getty Images

  • Affects: approximately 1.5 million Americans
  • Symptoms: joint pain, sores, bruising, fatigue, and rashes that look like scars
  • Misdiagnosed as: celiac disease, rheumatoid arthritis, or autoimmune thyroid disease

Often overlooked by doctors, this degenerative autoimmune disorder tricks the body into thinking brain and organ tissue are hostile and attacking it, according to Prevention. Sadly, lupus is incurable and tends to appear between the teen years and mid-40s.

Next: A dangerous condition that runs deep

6. Deep vein thrombosis

Man sitting and stretching

Sitting all day can raise your risk of developing deep vein thrombosis. | iStock.com

  • Affects: approximately 900,000 Americans
  • Symptoms: redness, pain, swelling, warmth, and tenderness in the affected area
  • Often goes undetected due to lack of symptoms.

Deep vein thrombosis is a blood clot that forms in a vein, often in the lower leg or thigh. If the clot breaks loose and travels to your lungs, this can cause serious lung damage, or death. The National Heart, Lung, and Blood Institute says only about half of those with DVT experience symptoms. A doctor can test you for blood clots, but it’s important to regularly move to lower your risk, too.

Next: Make sure you pass the test for this disease.

5. Gonorrhea

Couple sleeping in bed

Gonorrhea is a very common STD. | iStock.com

  • Affects: about 470,000 Americans
  • Symptoms: burning during urination, swollen testicles, vaginal bleeding, and painful urination
  • Misdiagnosed as: urinary tract infection

According to the CDC, gonorrhea is another common STD without symptoms. And symptoms, especially in women, can be mistaken for a bladder infection. As with all STDs, condoms greatly reduce your risk.

Next: This horrible disease will “tick” you off.

4. Lyme disease

A tick

This little guy can hurt you big-time. | nechaev-kon/Getty Images

  • Affects: 300,000 cases each year
  • Symptoms: bulls-eye rash at bite site, stiff neck, face twitching, nausea, vomiting
  • Misdiagnosed as: flu, meningitis, mononucleosis, chronic fatigue syndrome, fibromyalgia

This systemic infection, spread via an infected tick bite, can be treated with antibiotics. However, you can develop a syndrome post-treatment, which requires medication for pain management. As AARP explains, blood tests can determine this illness if no rash is present.

Next: This type of cancer masquerades as gas and cramps.

3. Colon cancer

Man holding stomach as he struggles with constipation

Colon cancer often has no signs or symptoms. | iStock.com

  • Affects: about 140,000 Americans
  • Symptoms: gas, cramps, diarrhea, fatigue, constipation, weight loss
  • Misdiagnosed as: hemorrhoids, Crohn’s disease, irritable bowel syndrome, or ulcerative colitis

The third most commonly diagnosed cancer starts in the large intestine as small polyps that grow to become cancer. Past the first stages, colon cancer causes diarrhea or constipation. Though colon cancer is one of the most treatable cancers in its early stages, many people skip screenings and don’t discover it until it’s too late.

Next: Another secretive cancer that can creep up on you

2. Oral cancer

girl with a serious sore throat

Lesions can trigger other symptoms. | patrisyu/iStock/Getty Images

  • Affects: 51,540 Americans annually
  • Symptoms: changes in speech, swelling issues, or a consistently sore throat
  • Misdiagnosed as: lesions

Your doctor may misdiagnose tongue or tonsil cancer if you don’t have a history of smoking. However, according to CBS News, “One in five of these cancers is attributable not to tobacco use but to infection with human papillomavirus (HPV).” Once it spreads to the lymph nodes, a doctor may catch it; before then it may only appear as lesions in the back of the throat.

Next: A cross between three horrible diseases

1. Huntington’s disease

Doctor holding a tablet to give diagnosis

Huntington’s disease is incurable. | iStock.com

  • Affects: 30,000 Americans
  • Symptoms: amnesia, mental confusion, muscle spasms, difficulty speaking
  • Misdiagnosed as: schizophrenia, conversion disorder

Rare but fatal, Huntington’s breaks down your brain’s nerves, explains the Huntington’s Disease Society of America. You can have the genetic disorder through adolescence without knowing it. The symptoms are a cross between ALS, Parkinson’s, and Alzheimer’s. You may notice symptoms between the ages of 30 and 50, but it’s tough to detect.