Hidden contacts with penicillin.

There is much evidence to indicate that the most common cause of drug allergy in recent years has been penicillin, and sensitive patients are warned to avoid treatment with this antibiotic. There are, however, a number of less obvious ways in which the penicillin-sensitive person may be exposed to the risk of contact with this drug, even minute amounts of which have been shown to cause allergic reactions. Four of the main hidden sources of such contact are discussed in detail in this paper.