Pili Annulati and Trichorrhexis Nodosa in the Same Patient: Cause or Coincidence?

PURPOSE To determine the relationship between pili annulati (PA) and acquired trichorrhexis nodosa (TN) seen in the same patient, considering the two main theories evoked by previous studies: greater stiffness of darker PA bands or associated cuticular damage. PROCEDURES Light microscopy of hair shafts from different regions of the patient's scalp. RESULTS TN was not superimposed to dark bands of PA. CONCLUSIONS Greater stiffness of darker PA bands was excluded as the cause of hair breakage. Hair breakage in PA patients might be related to cuticular abnormalities, as previously reported. Because weathering of long thin chemically treated hairs is extremely common, coincidence cannot be completely ruled out in this case.