Organophosphate poisoning is one of the most common toxicologic emergencies in Korea. Acute organophosphate poisoning and delayed polyneuropathy by ingestion are well published. There have been several reports about intermediate syndrome in organophosphate poisoning by ingestion but few about intermediate syndrome via dermal route.

We observed a 59-years-old male who had weakness of proximal limb muscles and respiratory muscles 2 days after dermal exposure by unidentified pesticide. The paralytic symptoms lasted up to 20 days but the delayed polyneuropathy did not develop. The patient needed mechanical ventilatory support for 2 weeks and had completely recovered from IMS 6 weeks later. Electrophysiological study was characterized by an axonal polyneuropathy pattern on the proximal limb muscles. Serum acetylcholinesterase level was below half of normal level. Clinical manifestations and electrophysiological study support the clinical diagnosis of intermediate syndrome.

Intermediate syndrome is commonly developed by ingestion of organophosphate but, as in this case, dermal absorption can also lead to intermediate syndrome. More detailed history taking and close observation is needed for about 3 or more days after intoxication because of the risk of respiratory failure.