Hands rely on a symphony of body systems to function properly, so doctors often look to these appendages for signs of illness and disease.
Doctors don’t have to be palm readers to make incredible predictions about your health. Your hands speak volumes, especially when something’s not working right. Their form, function, and appearance can offer important prognostic and diagnostic clues.
“You can learn a lot by looking at the hands,” agrees Kelly Weselman, MD, communications chair for the American College of Rheumatology and a rheumatologist with WellStar Rheumatology in Smyrna, Georgia.
We asked Dr. Weselman and other medical specialists, including a neurologist, cardiologist, and dermatologist, to share common and quirky things they look for when examining the hands and what these signs and symptoms could mean. You might be shocked to learn what your hands divulge.
The symptom: Weak hand grip
In business, a wimpy handshake says something about your personality. In medicine, it can be a sign of deteriorating health.
“During the physical exam for patients, we definitely pay attention to someone’s hand grip,” says Anne Albers, MD, a cardiologist with OhioHealth Heart & Vascular Physicians in Columbus. “We associate it with frailty,” she says.
Decreased grip strength coupled with a slow gait may actually portend a higher risk of death from heart disease in the elderly, according to a 2016 review in the International Journal of Cardiology.
More recently, a PLOS One study of adults 40 to 69 found stronger hand grip may be a sign of healthy heart function and structure. Based on these findings, researchers suspect hand grip could one day become a useful measure for identifying people at high risk of developing heart disease.
The symptom: Tiny red bumps or blisters
A red rash on your hand or wrist, sometimes morphing into oozing blisters, may be a sign of nickel allergy. Sensitivity to nickel is one of the most common causes of allergic contact dermatitis, according to the American Academy of Dermatology.
Lots of objects that touch your skin contain nickel: bracelets, watches, rings, even cell phones. But did you know you can also develop a hand rash from ingesting foods containing nickel?
“Nickel is especially high in beans, chocolate, peanuts, soy, oatmeal, and granola,” says Salma Faghri de la Feld, MD, assistant professor in the department of dermatology at Emory University in Atlanta. “You can determine if this applies to you by doing a trial of avoiding foods with nickel,” she says.
The symptom: Numb or tingly hands
Pins and needles in your hands? If you’re a young, healthy person, it’s likely carpal tunnel syndrome.
Many people experience nighttime tingling or numbness because they sleep with their wrists bent. That bend compresses the median nerve leading from the wrist to the hand, explains the American Academy of Orthopedic Surgeons.
Your doctor may order an EMG (electromyogram) to look for nerve or muscle damage, says Matthew Barrett, MD, assistant professor of neurology at the University of Virginia Health System in Charlottesville. Carpal tunnel treatments range from splints to surgery, he says.
But there are lots of other reasons for hand numbness and tingling. For example, you might experience temporary tingling in your fingers if you’re hyperventilating because you’re anxious, he says.
One cautionary note: “Any sudden onset of numbness or weakness (of the arms or hands) should always make someone worried about potential stroke,” Dr. Barrett adds. In that event, call 911.
The symptom: Trigger finger
Yes, trigger finger (also called stenosing tenosynovitis) is a real thing. It means you have a finger that pops, catches, or gets stuck when you try to bend and straighten it. Triggering is more common in women than men and most often affects the ring finger or thumb.
What happens is that a tendon (a rope-like structure connecting bone to muscle) or the tunnel it runs through becomes inflamed, making it harder for the tendon to move.
Anyone can get trigger finger. But you see it more often in people with inflammatory forms of arthritis, thyroid disease, and diabetes, as well as people who use their hands a lot, Dr. Weselman observes.
The symptom: Red scales or pus-filled bumps
Psoriasis is a chronic autoimmune condition that causes scaling on the skin’s surface and can show up on the hands or nails.
“Psoriasis on the hands can look like red, scaly, raised plaques and can sometimes include pustules—white pus bumps—on the palms,” Dr. de la Feld says.
Nail changes, like pitting, yellowish staining under the nail, or separation of the nail from the nail bed, also can occur, she adds.
If you think you have psoriasis, it’s important to get diagnosed. As Dr. de la Feld points out, “Psoriasis may be associated with many comorbidities, including arthritis and cardiovascular disease.”
The symptom: White, blue, or red fingers
If your fingers blanch (meaning they lose their color) and then turn blue (or purple or black) when it’s cold or you’re stressed, it’s a good bet you have Raynaud’s.
A sudden change in temperature or emotional state can trigger this condition, which results in a temporary loss of blood flow to the fingers or toes. Raynaud’s can make your fingers feel numb, cold, or painful, according to the National Heart, Lung, and Blood Institute. As blood flow resumes, your digits may throb or tingle and turn red.
“We see a lot of Raynaud’s,” especially in young women, Dr. Weselman says. “It can be something that stands alone … and is not dangerous. It’s just irritating,” she explains. “Or, it could be something that’s related to an underlying autoimmune disease, most often lupus or scleroderma.”
The symptom: Hand tremor
Sometimes hand shakiness is no big deal, and other times it can be a sign of neurologic disease.
Everyone has a little bit of shakiness in their hands (think about the last time you did something very precise, like threading a needle). This is a called a physiologic tremor, Dr. Barrett explains, and when you’re sleep deprived, over-caffeinated, taking certain medicines, or going through alcohol withdrawal, it becomes more noticeable.
Another type of tremor, called essential tremor, causes hand and arm shakiness on both sides of the body. It often runs in families and is present with action, whenever someone is performing a manual task like eating, Dr. Barrett says.
And then there are various disease-related tremors. Parkinsonian tremor, for example, usually involves one hand, or is more prominent in one hand. The tremor occurs when the hand is at rest.
“If combined with slowness of movement and stiffness in the limb affected by the tremor, it could be consistent with Parkinson’s disease,” he says.
The symptom: Purple finger nodules
When Dr. Albers sees patients with painful, red or purple bumps on their fingertips (called Osler nodes), the diagnosis is almost a given: “It’s very specific to endocarditis,” she says, a bacterial infection of the heart valves.
Endocarditis can also cause bleeding under the skin of the palms, leaving purple or brown spots, as well as bleeding under the nail or in the skin near the nail.
Skin symptoms can come and go, but “usually someone has signs of infection,” like a fever and sweats, she explains. “So it’s part of a whole picture that can suggest endocarditis.”
The symptom: Hand pain, stiffness, and swelling
When rheumatologists see women whose hands are hurting and inflamed, they think of various inflammatory diseases that could be causing the symptoms.
Possible culprits include rheumatoid arthritis, psoriatic arthritis, lupus, vasculitis (inflammation of the blood vessels), scleroderma (a connective tissue disease), and dermatomyositis (a skin and muscle disease).
Swollen hands may even suggest inflammatory bowel disease, Dr. Weselman says. “It’s more commonly going to affect the knees and the ankles,” she says. “But it’s not out of the question that it could affect the hands.”
The symptom: Long ring fingers
Scientists consider digit ratio—the length of the second (pointer or index) finger compared to the length of the fourth (ring) finger—a marker of testosterone exposure in the womb. In women, the pointer and ring fingers are usually about the same length. Men tend to have longer ring fingers and shorter pointers, or “low” digit ratios.
Could finger length predict a person’s athletic prowess? No one knows for sure, but there’s some research linking low digit ratios to better performance in sports like rugby, surfing, rowing, and sprinting.
What about cognitive abilities or disease risk? Again, no one has proved a cause-and-effect relationship. But a UK research team found people with ALS (amyotrophic lateral sclerosis) had lower digit ratios than a control group. And a Norwegian study found women with higher levels of prenatal testosterone exposure (as measured by digit ratio) did better on spatial tasks than women with low levels.