"Flushing occurs because the vasomotor system - the part of the brain that controls temperature in the body - dilates your vessels, veins and arteries to give the blood a bigger surface area and therefore cool it down," The Daily Mail quoted Angela Chalmers, pharmacist for Boots, as saying.
"It's called vasodilation and that's why you go red. There's a bigger blood flow around the body.
"You flush if you're embarrassed because neurotransmitters in your brain signal this emotion and that causes the central nervous system to produce chemicals which make the vessels dilate," she added.
During warmer months, flushing can simply be caused by the heat. Yet in women, flushing can also be associated with the menopause.
"The hormone oestrogen regulates the hypothalamus which is the heat stabilisation centre in the brain, so when your oestrogen is low, it can cause hot flushes," Chalmers said.
"There's some evidence that the herb black cohosh is very effective at treating hormonal flushing because it mimics oestrogen.
"There's also anecdotal evidence that sepia tablets - a homeopathic remedy - can help flushes. I have had many patients who found that it helped," she added.
A cause of flushing can be a skin condition called rosacea, which flares up in heat and also causes redness and broken veins, mainly in the face.
"I see four or five patients a week with rosacea," says consultant dermatologist John Lear from BMI The Alexandra Hospital in Cheadle, Cheshire.
"We think it's probably an inflammatory reaction to organisms on the skin but it can usually be treated with oral or topical antibiotics," Lear added.
Although rare, flushing can also be a symptom of carcinoid syndrome, caused by hormone-releasing tumours in the small intestine, colon, bronchial tubes or appendix.