Ahead, 10 itches you should never scratch. Get The Healthy by Reader's Digest newsletter  Itches you shouldn't scratch 1.

Medically reviewed by William Truswell, MD Dandruff is a mild form of seborrheic dermatitis caused by an overgrowth of the yeast (fungus) Malassezia. It causes oiliness, dryness, white or yellow ...

That flaky stuff on your head isn't just irritating and unsightly — it can lead to hair loss too, experts caution.