Putting substances where it is known you will come in contact with them (could be anywhere, desk, door handle, your bed, your clothes) that will irritate your skin, causing rashes or lesions.
Putting additives that do this in your personal hygine or skin care products. It seeks as though during a Break in, Vaseline or some oily substance was put in my body and face lotions.
Could also be from exposure to DEWs