We report here a 14-year-old girl with diffuse partial woolly hair. The patient presented mild hair loss associated with the presence of fine, short and kinky hairs closely interspersed with the normal hair throughout the scalp. The pathology of the scalp revealed the presence of intermediate-sized hair follicles regularly intermingled with normal follicles in each follicular unit. The possibility that diffuse partial woolly hair may result from a progressive miniaturization of the hair follicles may explain the presence of evident hair thinning in several adult patients affected by this rare abnormality.