Telling them apart
Dry scalp flakes are small, white and dusty, and the skin feels tight. Dandruff flakes are larger, oilier and often yellowish. Scalp eczema comes with red, sore patches you can feel with your fingertips.
Washing more helps one and worsens another, which is why generic advice fails so often.
What to do about each
Dry scalp wants less washing and more oil. Dandruff wants regular clarifying and less oil sitting on the skin. Scalp eczema wants gentleness above all else and often takes the longest to settle.