Many are confused between Dandruff and White Piedra. Both are fungal infections and caused by different reasons.
White Piedra is an infection of the hair shaft which is caused by a fungus variety known as Trichosporon, which is found in soil and dirty water. This spreads to bad habits like not washing hair regularly, sharing combs or pillows, using dirty water to wash hair etc.
Also dandruff is different from dry skin. Everyone experiences dry skin which can be seen on scalp, face, nose, ears, fingers, feet (dead skin) etc. This can be controlled by taking less oily food, reducing cheese/butter, avoiding pickles, by doing oil pulling in morning (mouth, nostrils and ears with sesame seeds oil).