Why do some stretch marks itch?

Some stretch marks itch because the skin is inflamed after stretching out unexpectedly. Inflammation, which is the body’s immune system trying to take care of itself, can itch in the same way that inflamed pimples, cuts, and burns can itch.1 Stretch marks itch as a biological response to an injury, like it’s trying to tell you hello out there, I’m hurt!

“The collagen is trying to form but the body’s not making enough collagen,” says Dr. Shirley Chi, a board-certified dermatologist at the Center for Advanced Dermatology in Arcadia, CA. “That’s what causes the itch.” If there had been enough collagen to support the expanding skin, it wouldn’t have torn. Dr. Chi might suggest a heavy moisturizer for itchy stretch marks, or an oral antihistamine allergy medicine for more severe cases.

References:
1Understanding the pathophysiology of itch by Lilit Garibyan et al. Dermatol Ther.