Seborrheic dermatitis3% to 5% - The percentage of cases of seborrheic dermatitis observed across the world's population.
It mainly affected infants of less than 3 months and adults of 20 to 40 years.
Psoriasis1% to 3% - The percentage of the population affected by this disease, that affects generally the whole body (including the scalp).
90% - The percentage of cases where the form psoriasis called "plaque psoriasis" is diagnosed.
45% to 82% - The percentage of people infected by scalp psoriasis when it is diagnosed elsewhere on the body.
50% - The percentage of people with scalp psoriasis that can observe red plates or crusts on the most part of their head.