Pruning by itself is generally harmless and goes away on its own. Extended pruning or pruning that doesn’t occur as a result of water, however, can be a symptom of an underlying medical issue.

If you’ve ever taken a long bath or spent time in a pool, you’ve probably noticed your fingers pruning. The tips of your fingers, and sometimes the fingers as a whole, develop wrinkles and creases that resemble those on a prune.

Water can have this effect, but there are other causes as well. For instance, the pruning can happen due to fluid or nerve damage, both of which can signal an underlying medical condition.

The medical community used to believe that pruning was caused by your fingers absorbing water. It is now known that pruney fingers are the result of blood vessels that constrict below the surface of the skin. The condition is tied to the function of the nervous system.

While pruney fingers due to immersion in water is not a problem and will resolve quickly once the fingers are dry, other conditions can cause pruning without water.

Dehydration

When you don’t drink enough water, your skin loses some of its elasticity. This can result in pruney fingers and other parts of your body.

Adults should drink six to eight glasses of water per day, especially during or after exercise, or in hot weather.

Other drinks, such as juice, soft drinks, and even tea, can make you more dehydrated. For this reason, don’t include these types of drinks when measuring your water intake. Other symptoms of dehydration include:

fatigue

dry mouth

dark yellow urine

dizziness

headaches

increased thirst

Learn more about dehydration.

Diabetes

High blood glucose levels from any type of diabetes can cause pruney fingers. Diabetes can damage the sweat glands, and the lack of sweat can cause dryness. There are three types of diabetes: type 1, type 2, and gestational. Many of the symptoms overlap between the three variations and include:

frequent urination

increased thirst

extreme hunger

fatigue

high ketones in urine

blurred vision

unexplained weight loss

frequent infections

Learn more about type 1 and type 2 diabetes.

Thyroid disorder

The thyroid gland — which is inside the neck and shaped like a butterfly — is responsible for body temperature and metabolism regulation.

Your thyroid regulates how you break down food and whether that food is used for immediate energy or is stored away.

Those with a thyroid disorder can have pruney fingers, as well as a skin rash, which can also cause prune-like wrinkles. Thyroid disorders have other symptoms as well, depending on the type:

Hypothyroidism

puffy face

fatigue

constipation

weight gain

increased sensitivity to cold

pain and stiffness in the joints

thinning hair

Hyperthyroidism

sudden weight loss

sweating

increased appetite

tremor

increased sensitivity to heat

fine, brittle hair

menstrual changes

Learn more about hypothyroidism and hyperthyroidism.

Lymphedema

Swelling in the arms and legs is referred to as lymphedema. In most cases, just one limb is affected. But sometimes it can affect both arms or both legs. The swelling is caused by a blockage in the lymphatic system, usually as a result of the removal of or damage to your lymph nodes during cancer treatment. The lymph fluid isn’t able to drain properly and the fluid buildup causes swelling. When the swelling occurs in the arm, it can affect the fingers and cause pruney fingers. Other symptoms of lymphedema include:

a sensation of tightness or heaviness

aches or discomfort

decreased range of motion

hard or thick skin (fibrosis)

frequent infections

Learn more about lymphedema.

Lupus

Systematic lupus erythematosus, often referred to as “lupus,” is an autoimmune disease in which the immune system unnecessarily attacks itself, causing chronic inflammation.

When the inflammation occurs in the fingers, they might become red and pruney due to the swollen glands. Other symptoms of lupus vary widely, and many are present in other conditions not associated with lupus. Symptoms can include:

fatigue

rash

hair loss

fever

kidney problems

gastrointestinal problems

dry eyes and mouth

Learn more about lupus.

Vitamin B-12 deficiency

Vitamin B-12 is just one of the vitamins that can keep you from developing pruney fingers. It is responsible for blood formation, nerve function, cell metabolism, and DNA production. Most people aren’t deficient in this vitamin because it can be stored in the body for several years.

However, if you are vegan or vegetarian, you have an increased chance of being deficient in vitamin B-12, since it is present in meat, poultry, fish, and dairy. Symptoms of vitamin B-12 deficiency include:

anemia

poor balance

fatigue

shortness of breath

tingly feet

memory loss

Learn more about vitamin B-12 deficiency.