Irritant contact dermatitis due to synthetic undercast padding is rare complication of plaster cast treatment which is underreported in orthopedic literature. Pruritis was the main symptom a few days following the application of the cast in our patient. However, the symptoms were underestimated by the treating physician. Severe irritant contact dermatitis can occur against the polyester undercast padding and should be kept in mind in patients whom complaining of pruritis under the treatment of casting