An itchy scalp can vary from being a bit of a pain to feeling like its taking over and even feel a little embarrassing. There is a wide spectrum of conditions that can cause a troublesome scalp, from cradle cap to psoriasis to dandruff. These conditions can be treated with lots of different shampoos or lotions. It is very important to find out what is causing the problem so you can treat your scalp accordingly. A lot of these conditions can be caused by a reaction to Malassezia yeasts, this reaction causes the sebaceous gland (your oil gland) to produce too much sebum as a sort of defence mechanism and it is the dry sebum that is the scales and flakes "dandruff". These yeasts can cause reactions on the scalp, face, chest and back causing erythema patches which can be incredibly itchy.
Everyones trigger is different; stress is a major trigger, diet - eating too much sugar & bread, weather conditions - damp autumn time, and products!! I hear it a lot, "I have a really itchy scalp so I've been treating it with ....... " also a lot of homemade treatments like olive oil or coconut oil. These treatments may actually trigger outbreaks, the yeasts thrive on these fatty acids and see the oils as food. Infact in lab conditions this is what they would feed the Malassezia species to help them thrive for experiments.
So selecting the correct products is essential in controlling your condition and being consistent.