Bubble Hair: Never use a hair dyer on wet hair
Bubble hair is an acquired (you’re not born with it) hair shaft abnormality/dysplasia where hair bubbles (multiple air-filled spaces) form within the hair shaft.
It was first reported in literature in 1986.
It is a form of thermal (caused by heat) injury caused by direct application of high heat from a hair dryer or heating/curling tongs (and any other hair care equipment that overheats) to damp or wet hair.
Hair dryers operating at 175°C or more, and hair curling tongs operating at 125°C or more, and applied to the hair for one minute or more can cause bubble hair.
The hair shaft then looks like a sponge. It can have a single cavity/bubble or have a swiss cheese appearance.
Clinically, the hair will feel dry, brittle and it appears to be kinked. It also may break off over time, due to excessive fragility, and the condition may develop into a localized alopecia(hair loss).
The hair may appear to come out in clumps, and there have been reports of the overall texture of the hair changing from soft and naturally curly to straight and stiff in some cases.
On light microscopy and scanning electron microscopy you can visualise the bubbles and cavitations respectively.
How does this happen?
All hair fibers normally contain air-filled spaces called vacuoles. These spaces can also become filled with water when the hair is wet.
Too much heat makes the water in the hair fibre evaporate into steam. This vaporization of the water may force the spaces in the hair to expand, turning the hair into a sponge-like structure. The damaged hairs are weak and brittle as the bubbles destroy the integrity of the fiber.
It is also precipitated by concurrent chemical use.
How do you prevent and treat it?
Avoid intense or prolonged application of local heat to damp or wet hair. Overall, avoid using excessive heat and chemicals on the hair. Cutting off the old damaged hair will also help.