Headaches from chemical exposures.

Headaches are a common complaint after work place or environmental exposures. A striking index case led to a literature review which uncovered only limited information. We then performed a retrospective descriptive study of 50 subjects referred to University Clinics with the complaint of headaches associated with chemical exposures at their work place. Our data suggest a different headache may exist depending on whether the chemical exposure is routine and limited versus accidental and extensive. Low level work place chemical exposures appear to cause headaches that abate soon after cessation of the exposure. A single accidental and extensive exposure may lead to patient complaints of a new headache syndrome that may last from several months to years. The characteristics associated with the onset of a new headache syndrome from accidental chemical exposures includes: 1) An acute large quantity of exposure. 2) A short latency of onset of the heralding headache. 3) A severe intensity and long duration of the heralding headache. 4) New recurring headaches that were not experienced before the acute exposure. We suggest a possible term for this high exposure syndrome i.e. Chemical Headache Exposure Syndrome (CHES).