To cope with sweaty feet, ventilated shoes and pure cotton socks are a must. [Shanghai Daily]

Being invited into a friend's house is a sign of closeness the world round. But an invitation can be a problem for some when they have to take off their shoes in the corridor and take their stockinged feet inside.

Sweaty smelly feet are not rare in China, especially in the south where there are long spells of high temperatures and humidity. Apart from inherited factors, damp and hot environments, or nervousness, depression and stress can all lead to overactive sweat glands.

TCM explains it as a reflection of pathogenic heat and dampness inside the human body. Eating foods that expel pathogenic heat and dampness, like pearl barley, and soaking feet in special herbal solutions at night, can bring relief.

The palms and soles are where sweat glands are the most concentrated in the human body. There are 620 sweat glands in every square centimeters on the soles but only between 140 and 340 in other parts of the body. It is natural that feet sweat after running, walking or other physical exercise.

But for those who are overweight, have hyperthyroidism, diabetes or simply have a constitution of sweating more than usual, the problem can cause concern.

"People with sweaty feet often have overactive yang (hot) energy and malfunctioning spleens," says Dr Li Yongmei, chief physician of Longhua Hospital attached to Shanghai University of TCM.

As the spleen is responsible for sending fluids to the urinary system for expelling, its failure can lead to accumulated pathogenic dampness inside body. Just as water always flows downwards, pathogenic dampness tends to do the same and can result in sweaty feet and eczema.

Just sweating more from the feet is not a big deal, according to Dr Li, yet sweaty feet can easily lead to eczema if there are also unhealthy habits such as not washing regularly or changing socks often enough.

"The hot and damp environment created by airtight shoes also makes an environment where eumycete or fungal mould grows and reproduces. And that's where the headaches start," says Dr Li. Inflammation or ulcers often occur because patients scratch the itchy outbreaks of eczema.