ABSTRACT
Hair shaft breakage is a common condition frequently caused by physical or chemical trauma as well as intrinsic diseases. The hair can be modified both externally and internally through the cosmetically-used chemicals. Use of these products causes a decrease in the hair shaft's elastic properties, allowing increased hair breakage. Herein we report four cases of hair shaft breakage presented with features of alopecia caused by hair care cosmetics. Microscopic examination revealed abnormal hair shaft endings such as weathering, trichoptilosis and trichoclasis. Through these cases, we remind the fact that the dermatologist can better aid the patient with hair difficulties if he or she has an understanding of the formulation and the effects of products designed to modify the hair.