Effect of pine-tar bath on disease severity in moderate-to-severe childhood eczema: an investigator-blinded, crossover, randomized clinical trial

Abstract

Background Atopic dermatitis (AD) is a chronic inflammatory disease associated with pruritus and sleep loss. Pine-tar has long been used for various chronic skin conditions in which its polycyclic aromatic hydrocarbon (PAH) component is anti-inflammatory and its resin acids antiseptic. The null hypothesis of this trial is that there is no difference in clinical efficacy between a pine-tar product and its vehicle for AD. Methods A 3-month, investigator-blinded, crossover, randomized control trial (RCT) was conducted in which each patient was assigned to bathing with pine-tar bath oil for one month and vehicle bath oil for another, with a washout period of 1-month in-between. Acceptability and efficacy of the bath products were measured. Disease severity scores (scoring atopic dermatitis (SCORAD) and patient-oriented eczema measure (POEM), quality of life questionnaires, noninvasive skin biophysiological measurements, blood IgE levels, and Staphylococcus aureus (SA) colonization status were assessed before and following bathing. Results Significant improvements were found in total SCORAD (p = .030), POEM (p = .004), SA colonization status (p = .002), and log-transformed IgE level (p = .009) among patients who bathed with pine-tar in the overall RCT study using intention-to-treat analysis. For per protocol analysis, significant improvements were found in total SCORAD (p = .024), objective SCORAD (p = .011), extent (p = .014), intensity (p = .032), pruritus (p = .047), POEM (p = .044), SA colonization status (p = .035), and log-transformed IgE level (p = .028). Acceptability to both bath-oils was good, and no product-related serious adverse events were recorded. Conclusions Bathing with pine-tar is an efficacious and recommendable adjuvant practice for AD patients. Disease improvement is associated with reduction of SA and IgE.