Immediate and delayed allergic contact reactions to polyethylene glycol.

The lower molecular weight liquid polyethylene glycols (PEG) varying from 200 to 700 are extensively used as solvent vehicles in topical medicaments. Four patients showed allergic reactions to these liquid polyethylene glycols in topical medications. Two had immediate urticarial reactions to PEG 400. Two other patients had delayed allergic eczematous reactions, one to PEG 200, and one to PEG 300. Cross reactions occurred between PEG 200, 300 and 400, but not between these liquid polyethylenes and the higher molecular weight solid polyethylenes from 1000 to 6000.