Fibreglass dermatitis is a common occupationally acquired irritant contact dermatitis, where small spicules of fibreglass lodging in the stratum corneum result in mechanical irritation. We present two patients, an air-conditioning ducting worker and an injection moulding machine operator, who both presented with generalized pruritus. In the first case, polarized microscopy of a skin biopsy specimen demonstrated rare small spicules, with a diameter of 1 µm, lodged in the stratum corneum. In the second case, skin tape stripping demonstrated fibreglass particles, not found on skin biopsy. Proper work practices, personal hygiene and use of impervious barrier materials were recommended. The first patient did not return for follow-up, and the second patient's dermatitis resolved after handling of fibreglass-containing material was eliminated from his job scope. In conclusion, we present two cases of fibreglass dermatitis to illustrate the challenges in diagnosis and highlight strategies for prevention.