Whitening or blanching of the skin is caused by

• A. Thermolysis
• B. Cold therapy
• C. Ultrasound
• D. Laser

Answer: (A)

Understanding how heat-based hair removal affects skin color is key here. In thermolysis, the high-frequency current rapidly heats the hair follicle and surrounding tissue. This sudden heating coagulates tissue and can momentarily disrupt tiny blood vessels, reducing blood flow in the immediate area and causing the skin to look pale or blanch. This whiteness is a sign that energy is being deposited and the follicle is being treated. Cold therapy would blanch from vasoconstriction, but that’s a different mechanism and not the primary effect described during thermolysis. Ultrasound and laser involve different tissue interactions and don’t produce the same immediate blanching pattern in this context.