There are two possibilities for this.
Scalp Eczema: this is a chronic condition of the skin where there is recurrent eczematous reactions. You will need prescription antimicrobicidials and steroids.
Scalp Psoriasis: Psoriasis, a condition which can affect any part of the body, can also affect the scalp. You need to use treatments like coal tar shampoos.
You should consult a dermatologist for this. You need to get this checked up to determine the cause. Once the diagnosis is made, you can be treated for this.
If you do not get an early appointment with a dermatologist and you are having a lot of symptoms, you can apply 1% Hydrocortisone ointment for this. This will help greatly. But if you are going to the dermatologist soon you should not apply as it will make the lesion subside and cause problems in diagnosis.
Take care - wish you good health and a quick recovery. Stay safe.
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Dr. P. Jyoti, MD