Seasonal variation in the occurrence of late adverse skin reactions to iodine-based contrast media.

PURPOSE: To study the possible seasonal effect in the occurrence of late adverse skin reactions to iodine-based contrast media (CM).

MATERIAL AND

METHODS

Data on 4,875 adult patients followed for late adverse reactions after i.v. injections of iohexol or iopamidol, or intra-arterial injection of ioxaglate were retrospectively investigated with respect to the amount of global radiation vs. the occurrence of reactions. The information on these reactions was collected from questionnaires that were filled out by the patients (out-patients) or by nurses (in-patients). The follow-up time was 24 h.

RESULTS

Fifty-two of 4,875 patients (1.07%) had experienced a late skin reaction (urticaria or rash); this number exceeds the reports on spontaneous occurrence of such reactions by a factor of 300. Most of the reactions in a known location occurred on sun-exposed areas of the body. A 2-month peak in the incidence of reactions (May to June) included 35% of all events (p<0.025) and a 3-month peak (April to June) 46% of all events (p<0.01). There was a significant rank correlation (r = 0.613, p<0.05) between the frequency of reactions and the mean amount of global radiation.

CONCLUSION

This study demonstrates a seasonal variation in skin reactions after intravascular injection of iodine-based CM. The possible photosensitising effect of these drugs should be further studied.