I am a registered and certified orthopaedic technologist working in an out-patient setting for many years. Over the years I have noticed that sometimes my patients acquire contact dermatitis underneath their casts, both plaster and fiberglass. I have researched this phenomena but have been unable to really gain an answer as to why this happens. Most of the articles I find about it just state simply that contact dermatitis is a side-effect of casting. But it doesn't seem to make sense, especially if the cast material itself does not come into contact with the skin. The answer seems to lie somewhere between the stockinette or webril. Anyone else working this field have any thoughts?