Contact dermatitis is the inflammation of the skin due to contact with any thing which can cause allergy leading to itching burning conditions. It is always non infected when it starts but continuous scratching can destroy skin of the affected area which is good medium for the opportunistic bacteria to grow. This can lead to infection and condition is called infected dermatitis.
I have oozing rash (burns and itches ) scaley behind my ear. Had hair dyed a couple of days ago