Common Health Issues You've Probably Never Heard Of

There are tens of thousands of health issues — from diseases, disorders, genetic conditions, and variations within the human body. You're probably very familiar with the most common medical issues facing Americans, including high blood pressure, type 2 diabetes, heart disease, and Alzheimer's disease. There are also less common conditions, like ALS (also known as Lou Gehrig's disease), that still get a lot of media attention, often because a celebrity or other famous figure has the condition. And, of course, there are rare diseases and disorders that only affect a few thousand people around the world that most people don't know much about. Nevertheless, there are a number of conditions out there that many people have never heard of even though they're actually relatively common.

As noted in a 2009 paper published in the American Journal of Medical Genetics, words like "common" and "rare" don't have standardized, universally agreed upon definitions when used to describe medical conditions. However, the National Institutes of Health gives us a good starting point, as it defines a "rare" disease as one that affects fewer than 200,000 Americans (approximately 1 in 1,640 people, or 0.06% of the population). Here's a look at some decidedly not rare conditions to look out for. 

Urachal anomalies

During the early weeks of pregnancy, a tube-like structure called the urachus allows waste to drain from the developing bladder through the umbilicus (belly button) and away from the fetus via the umbilical cord (via University of California, San Francisco). About 12 weeks through pregnancy, when it's no longer needed, the urachus "closes" and transforms into a fibrous piece of tissue that runs down the middle of the abdomen.

In some individuals, however, part or all of the urachus may remain intact. The entire tube may stay open, which can cause leakage of urine from the navel. In other cases, the tube may remain partially open, sometimes at the bladder or belly button end. The most common form of urachal anomaly is a small pocket of open tube somewhere in the middle that doesn't open to either the bladder or the navel (via the Radiological Society of North America).

While problems related to urachal remnants are extremely unlikely, having some portion of the tube remain open is actually quite common. According to the American Urological Association, they "can be seen incidentally in up to 32% of adult bladder autopsies or cystectomies." In addition to infection, urachal cancer is a very rare but possible complication.

Sjögren's syndrome

If you have chronic dry eye and dry mouth, you could have an autoimmune condition called Sjögren's syndrome. In those with this disorder, the immune system attacks the body's own cells as if they were dangerous invaders, according to the Mayo Clinic. The salivary glands and tear ducts are the areas most likely to be targeted, causing a decrease in production of saliva and tears. Other parts of the body, including the joints, thyroid, lungs, and skin, may also be affected. This can lead to symptoms such as joint pain and stiffness, extreme fatigue, dry skin, vaginal dryness, and a persistent dry cough.

Scientists aren't sure what causes Sjögren's syndrome, but it's most likely a combination of genes and a triggering event, such as a viral or bacterial infection. The condition affects more women than men, and it usually appears in those over 40. Individuals with Sjögren's are also much more likely to have another autoimmune condition, such as rheumatoid arthritis or lupus. As of this writing, there is no cure, but treatment can lessen symptoms. Medline Plus noted that Sjögren's syndrome may occur in up to 4 percent of Americans.


Everyone knows there are different blood types, but did you realize that most people express their blood type in other places besides their red blood cells? According to The Tech Interactive, which is run by the Department of Genetics at the Stanford School of Medicine, the ABO blood type group (A, B, AB, or O) refers to which antigens (sugars) are produced by red blood cells and present on their surface. But for most people, any cell that produces bodily fluid (think: sweat, saliva, or mucus) also produces a water-soluble form of the blood type antigen that floats freely in these fluids. These people (people with ABO blood) are known as "secretors" and make up about 80 percent of the population.

However, about 20 percent of individuals have a genetic mutation that prevents them from producing blood type antigens in their bodily fluids. These people are called "non-secretors." It's unclear how much of an effect your status as a secretor or non-secretor has on your health, but preliminary research suggests it may play a role in susceptibility to certain infections. Non-secretors appear to be significantly less susceptible to norovirus, the virus that causes most cases of stomach flu. They may also be less likely to get ulcers. On the flip side, they may be more likely to get pneumonia, yeast infections, and certain autoimmune conditions (via The Tech Interactive).

Lewy body dementia

Everyone has heard of Alzheimer's disease, and for good reason — it's the most common form of dementia affecting older Americans (via Alzheimer's Association). But you've likely never heard of the second most common form of dementia, even though it affects more than a million older adults in the United States. According to the National Institute on Aging, Lewy body dementia (LBD) is a condition caused by deposits of a protein called alpha-synuclein in the brain. These deposits, known as Lewy bodies, affect the brain's neurochemistry, which, in turn, impacts movement, cognition, memory, behavior, and mood.

LBD is actually an umbrella term for two different but related diagnoses: dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). Both conditions begin with movement-related issues, such as tremor, muscle stiffness, and lack of coordination. In DLB, however, cognitive symptoms appear quickly — within a year of movement-related symptoms. In PDD, cognitive impairments appear more gradually.

Unlike other forms of dementia, such as Alzheimer's, those with LBD are more likely to experience visual hallucinations and have more fluctuations in cognitive ability on a daily basis. They also often have REM sleep behavior disorder, causing them to act out their dreams by yelling, flailing, or falling out of bed.

Hidradenitis suppurativa

According to WebMD, "hidradenitis suppurativa (HS) is a condition that causes painful bumps under your skin in the hair roots near some of your sweat glands." Also known as acne inversa, the condition usually appears in the armpit, groin, buttocks, or inner thighs — basically, anywhere you have body hair or that gets sweaty and chafed. It involves hair follicles that become blocked, inflamed, painful, and sometimes itchy. Pockets of pus form under the skin, and small tunnels can form under the skin connecting the bumps. Bumps can last for months and may disappear and reappear in the same spot or general area.

The exact cause of HS is unknown, but it's most likely a combination of genetics and environmental triggers. Treatments may include a mix of at-home methods (such as NSAIDs and hot compresses), prescription medications, and lifestyle changes. In severe cases, surgery may be required. In addition to the painful, itchy bumps, HS can lead to abscesses (deep pockets of infection), significant scarring, and feelings of depression and isolation. The HS Foundation noted that this condition affects about 1 percent of the population, or 3 million Americans. Women, especially those with darker skin, are most likely to have HS.


Most people have a vague idea of what gout is but assume it's a long-extinct condition that once upon a time affected the overindulgent royalty of medieval Europe. The truth is that gout is actually still very common. WebMD estimates that gout affects 4 percent of the U.S. population — more than 8 million Americans — and rates of gout have been on the rise.

According to the Mayo Clinic, gout is a type of arthritis marked by sudden and severe pain in a particular joint, often the big toe. Gout is caused by "needlelike urate crystals" that form in joints or the surrounding tissue. Urate crystals are made of uric acid, a byproduct of breaking down substances called purines. Some foods, such as red meat, organ meats, beer, scallops, and tuna, contain high levels of purines. (Hence the connection to gluttonous kings of old.)

If you produce too much uric acid or your kidneys have a hard time getting rid of the uric acid you produce, it can build up and form urate crystals. Treatment options include changes in diet, medications like NSAIDs to combat the pain and inflammation of a gout attack, and medications that affect how much uric acid your body produces or excretes.


Iron-deficiency anemia is the most common nutritional deficiency, affecting approximately 20 percent of nonpregnant women, 50 percent of pregnant women, and 3 percent of men (via WebMD). But some individuals have the opposite problem: an excess of iron in the blood.

According to Medline Plus, this disorder, known as hereditary hemochromatosis, "causes the body to absorb too much iron from the diet. The excess iron is stored in the body's tissues and organs, particularly the skin, heart, liver, pancreas, and joints." There are several types of hemochromatosis, and about 1 million Americans have the most common version, type 1, of this genetic disorder. People of Northern European descent are most likely to carry the genes for hemochromatosis.

As iron builds up in the body, particularly the liver, it causes tissue damage. Initial symptoms of hemochromatosis include joint pain, abdominal pain, weakness, and fatigue. Over time, the accumulation of iron can cause liver disease, diabetes, heart problems, reproductive issues, and changes in skin color. Strange as it may sound, the best way to treat those with hemochromatosis is by simply removing blood. A pint is removed once or twice a week until iron levels return to normal, and then additional blood is removed every two to three months (via the Mayo Clinic).

Piriformis syndrome

According to a 2020 report in StatPearls, the piriformis is a long, flat muscle that attaches to the front of the spine at one end and the hip bone at the other. The piriformis helps externally rotate the hip. But, because the muscle runs alongside the sciatic nerve, it may entrap (compress) the nerve — a condition known as piriformis syndrome. 

Nerve entrapment can happen for a variety of reasons, including injury to the hip, an overdeveloped piriformis muscle in athletes, sitting for too long, and natural variations in hip anatomy. Whatever the cause, the symptoms tend to be the same: shooting, aching, or burning pain or tingling and numbness in the glutes that extends down the back of the leg.

About 2.4 million Americans experience piriformis syndrome each year. Women are six times as likely to have the condition as men. Treatment options include anti-inflammatory medications, steroid injections, and physical therapy to stretch the muscle and improve range of motion. In severe and difficult-to-treat cases, surgery may be required to decompress the sciatic nerve. Stretching the muscles of the hip and regularly taking a break from sitting to stand and walk around can help prevent piriformis syndrome.

Mycoplasma genitalium

Mycoplasma genitalium (Mgen) is one STI you probably never learned about in sex ed class. That's because, according to Patient, it's a relatively "new" bacteria. It was initially discovered in 1981, and a reliable laboratory test to screen for it wasn't developed until 2017. About 3 percent of adults worldwide are believed to be infected with this bacteria, and, as with other STIs, individuals who have multiple sexual partners or don't practice safe sex are most likely to get Mgen. Condoms (either male or female) can prevent spread of the bacteria from one person to another.

Symptoms of Mgen are similar to those of chlamydia. In men, symptoms include inflammation of the urethra, pain during urination or ejaculation, and discharge from the penis. Women may experience inflammation of the urethra or cervix, increased or unusual vaginal discharge, and bleeding between periods. If left untreated, Mgen can cause more severe complications, such as pelvic inflammatory disease. Although the bacteria can be killed with antibiotics, this STI is becoming resistant to many of these drugs. Because of this, experts fear it may become a "superbug" that won't be controllable with available medications.

Interstitial cystitis

A urinary tract infection isn't the only condition that can turn going pee into a real pain. According to the National Institute of Diabetes and Digestive and Kidney Diseases, interstitial cystitis (IC) is a chronic condition that causes unpleasant urinary symptoms. These symptoms vary from person to person but can include discomfort, pain, or tenderness in the pelvic area as well as intense bladder pain, frequent urination, and urinary urgency.

The cause of IC is unknown, though it may be related to other inflammatory conditions. IC is a "diagnosis of exclusion," according to Harvard Women's Health Watch. This means individuals are diagnosed with the condition only after other conditions have been ruled out. IC affects somewhere between 3 to 8 million women and 1 to 4 million men in the United States.

Unfortunately, there's no single treatment that works for all people with IC. Medications, such as NSAIDs, antidepressants, and antihistamines, may relieve some of the symptoms. Some prescription medications are placed directly in the bladder. Electrical stimulation of the nerves in the area can also provide relief for some. Lifestyle changes, such as avoiding certain bladder-irritating foods and training yourself to urinate on a set schedule, may also help (via the Mayo Clinic).

Horseshoe kidneys

When it comes to variations in human anatomy, horseshoe kidneys are relatively common. According to a 2021 report in StatPearls, horseshoe kidneys are "the most common fusion defect of the kidneys." Approximately 0.25 percent of Americans have the condition. So, what is it? Horseshoe kidneys means the kidneys are fused together, creating a U shape.

In 90 percent of cases they're fused together at the bottom; in the remaining 10 percent, they're fused at the top. Researchers believe the fusion happens between four and six weeks gestation. Horseshoe kidneys also sit a bit lower and forward than typical kidneys, which makes them more susceptible to damage if the abdomen incurs injury.

In many cases, horseshoe kidneys don't cause any problems. In fact, about one-third of individuals with horseshoe kidneys only discover they have the anomaly when an MRI or CT scan is done for some other complaint. Having horseshoe kidneys does, however, increase your risk for certain conditions, including kidney stones, kidney infections, and obstructions in the urinary tract (via Verywell Health). The risk of certain forms of kidney cancer also increases.

Klinefelter syndrome

Usually, biological females have two X chromosomes and biological males have an X and a Y. But there are a number of variations that can occur, such as a single X, triple X, and, in the case of Klinefelter syndrome, XXY. As Medline Plus explained, males born with an extra X chromosome typically have smaller than average testicles that produce low amounts of testosterone.

Once puberty hits, this hormone imbalance can lead to breast enlargement, decreased muscle mass and bone density, reduced amounts of body and facial hair, and infertility. There may be other, more subtle, signs as well, including slightly taller than average height, curved pinky fingers, and flat feet. Individuals with Klinefelter syndrome often have learning disabilities and developmental delays. But, because these signs are pretty nonspecific and can be subtle, an estimated 75 percent of males with the condition are never diagnosed.

Although sex chromosome disorders don't happen frequently, Klinefelter syndrome is one of the most common, affecting approximately 1 in 650 newborn boys. The condition isn't inherited; it's caused by a "random error" that leaves an egg or a sperm cell with an extra X chromosome (via Medline Plus).

Frozen shoulder

According to a 2017 paper published in the journal Shoulder & Elbow, adhesive capsulitis, also known as "frozen shoulder," is a condition in which too much scar tissue forms in the shoulder joint. It can happen spontaneously or after a shoulder injury (such as a dislocation) or shoulder surgery. The condition begins with inflammation in the membrane surrounding the shoulder joint. Individuals experience shoulder pain, particularly at night and when the shoulder is at the end of its range of motion.

Over time, as bands of scar tissue called adhesions develop, the shoulder becomes stiff and individuals lose range of motion. In most cases, the frozen shoulder "thaws" in one to three years and the stiffness and pain subside. But 20 to 50 percent of affected individuals have symptoms that last longer. Physical therapy, medications including anti-inflammatories, and, in some severe cases, surgery, are used to help manage pain and improve the shoulder's range of motion.

Adhesive capsulitis affects between 3 and 5 percent of adults. However, as many as 20 percent of diabetics may have the condition. When the condition happens spontaneously, it often affects the nondominant arm, but in 40 to 50 percent of cases both arms are affected simultaneously.


All of us have felt a little funky from time to time when we stand up too fast, but for those with postural orthostatic tachycardia syndrome (POTS), the change from sitting or lying to standing is extreme. According to Dysautonomia International, POTS is a type of dysautonomia, a malfunction of the autonomic nervous system (ANS). The ANS controls "automatic" functions like breathing, heart rate, and blood pressure.

Individuals with POTS experience an increase in heart rate of at least 30 beats per minute within 10 minutes of standing up (via POTS UK). This is sometimes accompanied by a drop in blood pressure. Those with POTS may also experience symptoms like fatigue, lightheadedness, headaches, heart palpitations, and shortness of breath, according to Johns Hopkins Medicine. POTS can have many underlying causes, and there are a variety of treatments to help manage symptoms, including increasing fluid and sodium intake, wearing compression socks, and taking medications like beta blockers.

An estimated 1 to 3 million Americans have POTS, and approximately 80 percent are women, Dysautonomia International confirmed. It's most prevalent in women of childbearing age. While some individuals have only mild symptoms that don't interfere too much with daily life, 25 percent of POTS patients are disabled by the condition and unable to work.