There are some common assumptions about it, that probably arent correct, says Brian S. Kim, M.D., co-director at the Center for the Study of Itch at Washington University School of Medicine. A classic is that people are less distracted at night and all of a sudden tune into the itch. I dont think its that simple, says Dr. Kim.

But its not clear exactly what the more complicated answer is yet, but one newer theory is that nighttime itching could be a result of end-of-day changing circadian rhythms, Dr. Kim says. At night, your anti-inflammatory chemicals are lower, which could regulate the sensitivity of itching. You may get a cleaner kind of signal from a nighttime itch, he says.

Evolutionarily, that might have served us well. Im getting really speculative here, but if you dont move at all at night, you may be more susceptible to getting infestations with mites, or even getting bitten by mosquitoes, says Dr. Kim.

Ask why peoples feet itch and dermatologists take a deep breath, because there can be a huge number of drivers. Some simple, others not so much. Causes can include:

When a patient comes in and complains of itchy feet, the first thing a dermatologist usually does is look between the toes to see if theres redness, cracking, flaking, or scaling, says Shawn Kwatra, M.D., assistant professor of dermatology at Johns Hopkins Medicine. Those often indicate athletes foot, and remedies include keeping your feet as dry as possible and using an over-the-counter anti-fungal product.

As you get older, you have less of an ability to retain water in the outer layer of skin, says Dr. Kwatra. On top of that, since youre walking on your feet all day, they can be thickened and dry, anyway. All of which adds up to extra itch on your feet. Help stop it by applying moisturizing cream-the kind that comes in a jar-on your feet at night. Cream is more moisturizing than lotion, Dr. Kwatra points out. The more gooey it is, the more moisturizing it is.

These usually make the rest of your body itchy, and the feet arent exempt from feeling it.

Nerve damage caused by unchecked diabetes can cause itching in the feet, as can liver disease. Sometimes, Dr. Kwatra says, itch on the body can be a harbinger of underlying illness. Most of the time, itch that hints at an underlying illness wont just be in your feet. Take it in context with the rest of your health, he says. In other words, not every itchy foot is going to be the sign of a big issue like these, but if itchy feet are a consistent and long-standing problem for you, get yourself checked out, says Dr. Kwatra.

Itching may be a result of multiple system failures, says Dr. Kim. Itch may not just be one symptom, there may be many forms of itch. Itch is almost a field of medicine onto itself, he says. And only the surface has been scratched, so to speak.

The toolbox is pretty straightforward: