Hot Combs and Thermal Pressing
Heat has a wonderful ability to modify the structure of hair. The application of heat to hair can break hydrogen bonds (chemical bonds) that were responsible for the original shape of the hair. Unless the hair comes into contact with water, the hair will maintain the new shape.
Hot combing involves application of temperatures 300-450 F. A pressing oil may be applied prior to the hot combing. The practice is safe for many individuals and can provide remarkable straightening effects. It is not however without side effects.
Damage to the hair shaft and scalp burns are among the potential risks. The temperate settings can be adjusted depending on a patient's specific hair qualities. This does not however completely eliminate risk.
Hair shaft damage (called trichorrhexis nodosa) is commonly seen no matter how careful one is. The combination of heat styling to “chemically relaxed” hair is more likely to lead to hair damage.
In general, limiting heat to 350 F and application once per week or less is a recommended starting routine for those who do wish to use heat. It does not eliminate risk but reduces it considerably. The safest way to treat hair is to do absolutely nothing to it. But we are only human and simply being practical goes a long way.
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Vancouver office at 604.283.9299