© 2017, Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.Casting application is one of the essential aspects with respect to conservative treatment of fractures in Orthopaedics and it may be applied after surgical treatment when needed. In the recent years, common use of synthetic cast (45% polyurethane resin and 55% fiberglass) and also undercast cotton padding (synthetic fiber) caused an increased incidence of allergic contact dermatitis. It may develop an allergic reaction progressing accompanied by eruptions and itching as commonly experienced in our daily orthopaedic practice. We have presented a case of allergic contact dermatitis which mimics an unusual manifestation of cellulitis in routine clinical practice.