Contact urticaria and anaphylaxis to the fungicide chlorothalonil.

Chlorothalonil, a common fungicide used for agricultural and horticultural purposes is capable of eliciting contact urticaria. In our patient, an anaphylactoid reaction resulted from intact skin contact to diluted chlorothalonil (0.01 percent aqueous). Our patient also experienced immediate respiratory reactions such as a tight chest and throat after entering the nursery greenhouse, without direct skin contact with chlorothalonil.