Dandruff is generally caused by fungi living on the scalp. The fungi eat up your skin and make it dry. The dry skin flakes off. Dandruff shampoos work by killi

Dandruff is generally caused by fungi living on the scalp. The fungi eat up your skin and make it dry. The dry skin flakes off. Dandruff shampoos work by killing the fungi. There are three main types of anti-fungals, zinc pyrithione is used in Head and Shoulders, selenium disulfide in Selson Blue. There is a third one not commonly used called ketoconazole that you may want to try. There is also coal tar shampoo, which is not an anti-fungal, instead it slows skin cell growth and sloughs off the dead skin. Selson Blue works well for me, I use it daily. If I go off of it for a few days the dandruff kicks into high gear. The thing about dandruff shampoos is you have to use them with a certain regularity because even if you kill the fungi, the condition takes a few days to clear up, the damage to your scalp is done. You need to create a hostile environment for the microorganisms, and that takes time. Your dandruff is probably caused by only one type of organism that thrives in particular climates. Next time you're there, you might get ahold of two or three shampoos and try them for a week each and see if it clears up. Then you know which is 'your' anti-fungal.