Clinical Question: Is tea tree oil shampoo effective in the treatment of dandruff?

Setting: Outpatient (specialty)

Study Design: Randomized controlled trial (single-blinded)

Synopsis: Tea tree oil has antifungal activity and, thus, may be useful in the treatment of dandruff. A total of 126 patients, 14 years or older, were randomized (allocation concealment uncertain) to receive 5 percent tea tree oil shampoo or the vehicle shampoo as a placebo. Patients washed their hair daily, leaving the shampoo in for three minutes before rinsing. Tea tree oil has a distinctive odor, so patients were likely to know their treatment group status. Outcomes were assessed by a scalp lesion scoring system. To blind the outcome assessment, patients were asked not to apply shampoo on the assessment days. Only one patient was lost to follow-up after four weeks.

Using intention-to-treat analysis, the whole scalp lesion score was significantly lower in patients using 5 percent tea tree oil shampoo compared with those using placebo (baseline score, 91.0; down to 53.0 after four weeks versus baseline score, 99.7; down to 88.2 after four weeks; P <.001). Patient self-assessment scores of itchiness improved by 23 percent in the subjects using tea tree oil shampoo compared with 12 percent in the group using placebo (P <.03). Greasiness and scaliness scores also were lower in the tea tree oil group, but only one patient in each group was completely free of dandruff at the end of four weeks. No serious adverse events were reported.

Bottom Line: Five percent tea tree oil shampoo is effective and well tolerated in the treatment of dandruff. (Level of Evidence: 1b)