I notice that my scalp itches more when the relative humidity outside is high. On cold winter days when the relative humidity is lower than usual and we rely on artificial heating, I have no scalp itch. Since relative humidity is a measure of the amount of water/moisture in the air, this correlation would make sense in that the extra moisture is a catalyst for bacteria and other organisms that cause itchiness. Can you explain doc?? Thank you very much for your time.
While your theory is certainly plausible, I doubt bacteria are causing your scalp to itch. Maybe your skin type does not agree with the higher humidity. Conversely, others may find lower humidity may cause more scalp itching and skin drying. Get a dermatologist to examine you, as a starter.