Dandruff is when dead skin cells fall off the scalp. This is normal, as our skin is always being renewed. About half the population of the world suffers from an excessive amount of this shedding, which can be triggered by things like temperature or the increased activity of a microorganism that normally lives in everyone’s skin known as Malassezia globosa. Fortunately, dandruff is not contagious and there are many different treatments available, like specialised shampoo.