Natural coniferous resin lacquer in treatment of toenail onychomycosis: an observational study

Abstract

In in vitro tests, natural coniferous resin from the Norway spruce (Picea abies) is strongly antifungal. In this observational study, we tested the clinical effectiveness of a lacquer composed of spruce resin for topical treatment of onychomycosis. Thirty-seven patients with clinical diagnosis of onychomycosis were enrolled into the study. All patients used topical resin lacquer treatment daily for 9 months. A mycological culture and potassium hydroxide (KOH) stain were done from nail samples in the beginning and in the end of the study. Treatment was considered effective, if a mycological culture was negative and there was an apparent clinical cure. At study entry, 20 patients (20/37; 54%; 95% CI: 38-70) had a positive mycological culture and/or positive KOH stain for dermatophytes. At study end, the result of 13 patients was negative (13/19; 68%; 95% CI: 48-89). In one case (1/14; 7%; 95% CI: 0-21) the mycological culture was initially negative, but it turned positive during the study period. By 14 compliant patients (14/32; 44%; 95% CI: 27-61), resin lacquer treatment was considered clinically effective: complete healing took place in three cases (9%) and partial healing in 11 cases (85%). The results indicate some evidence of clinical efficacy of the natural coniferous resin used for topical treatment of onychomycosis.

Figure 1

Flow chart of the trial: data of the patients who had positive or negative mycological culture in the beginning of the study. ¹Trichophyton rubrum in 11 cases and Trichophyton mentagrophytes in four cases. ²Trichophyton rubrum in three cases and Trichophyton mentagrophytes in two cases. ³Trichophyton rubrum in one case and Trichophyton mentagrophytes in one case.

Figure 2

(a) Data of the patients who had positive and negative mycology (culture and/or KOH stain) in the beginning of the study. ¹Trichophyton rubrum in 11 cases and Trichophyton mentagrophytes in four cases. ²Trichophyton rubrum in four cases and Trichophyton mentagrophytes in two cases. ³Trichophyton mentagrophytes in one case. (b) Complete and partial healing rate among the 33 compliant patients. One patient was dropped due to missing photograph at the end of the study.

Figure 3

Photographs, mycological culture, KOH stain and the treatment result of 10 patients before (left panel) and after (right panel) resin lacquer treatment (a–t). Non-healed TDO (a, b) and partially healed DLSO (c, d). Partially healed WSO (e, f) and completely healed WSO (g, h). Two completely healed DLSO (i–l). Two partially healed DLSO (m–p). Two partially healed DLSO (q–t).