April 2003 / Vol. 52, No. 4
Patient Oriented Evidence that Matters
Practice Recommendations from Key Studies
Does 5% tea tree oil shampoo reduce dandruff?
Richard Prensner, MD
Harrisburg Family Practice Residency
Daily shampooing with 5% tea tree oil reduces the severity and extent of dandruff. Overall improvement is similar to topical treatment with ketoconazole or terbinafine.1,2 Tea tree oil is a good alternative for patients who prefer a natural product, don’t mind daily hair washing, and can tolerate the distinctive tea tree oil fragrance.
BACKGROUND: Since dandruff control requires long-term management, treatment choice will depend on ease and frequency of administration, costs, and side effect profiles of the therapeutic agents. Tea tree oil, a natural product, has antifungal activity against Pityrosporum ovale, which is thought to be the causative agent of dandruff.
POPULATION STUDIED: A total of 126 patients with chronic dandruff, 14 years of age or older, were recruited by advertising in Australia. Baseline severity was assessed by whole-scalp lesion scores. Exclusion criteria were very mild or very severe dandruff, significant change in severity during a 2-week washout period, or concomitant impacting clinical conditions.
STUDY DESIGN AND VALIDITY: Patients were randomized and matched for sex, race, dandruff severity, severity of symptoms, and medical history. The authors could not be contacted for specific information on randomization or allocation concealment. Since tea tree oil has a distinctive odor, patients were asked not to apply the test product the day of assessment to maintain blinding by those assessing outcomes. Subjects self-reported scaliness, itchiness, and greasiness. Only 1 patient was lost to follow-up after 4 weeks.
Recruiting through advertising may have influenced the type of patient and dandruff studied. The 4-week study period did not assure the absence of long-term problems. Since subjects could detect the smell of the active ingredient and were thus not blinded, self-assessments of scaliness, itchiness, and greasiness were prone to reporting bias. The severity scale criteria seem subjective, and there was no mention of intra- or interexaminer reliability. Analysis was intention-to-treat.
OUTCOMES MEASURED: Examiners evaluated subjects at 0, 2, and 4 weeks and measured the total dandruff area and severity score. Both scores multiplied together provided the whole-scalp lesion score.
RESULTS: The whole-scalp lesion score in the tea tree oil treatment group fell from 91.0 at baseline to 53.0 at 4 weeks (a 41.2% improvement) compared with an 11.2% improvement in the control group (mean change, 30%; 95% confidence interval, 15.9%–44.2%, P<.001). Patient self-assessment scores of itchiness improved by 23% in the tea tree oil group vs 12% in the placebo group (P=.03). Greasiness and scaliness scores were also less in the tea tree oil group compared to placebo.
Only 1 patient in each group was completely free of dandruff at the end of 4 weeks. No serious adverse events were reported.
- Johnson BA.
Treatment of seborrheic dermatitis. Am Fam Physician 2000;61:2703–2714.
- Bulmer AC.
The antifungal action of dandruff shampoos. Mycopathologia 1999;147:63–65.
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