Actinic Keratosis (AK) is that scaly, red, and occasionally itchy patch of skin, resembling a mole, that usually appears on patients over 50 years old, but can manifest in younger adults particularly with prolonged sun exposure. The percentage risk of an AK developing into an SCC (Squamous Cell Carcinoma) is unknown and it can’t be predicted which ones will progress and patients often have many lesions.
Often referred to as sunspots, or solar keratosis, the potential for these to morph into a melanoma is real and early treatment is the best option.
Current treatments include photodynamic therapy, topical diclofenac (Solaraze), topical imiquimod (Aldara and Zyclara) and topical fluorouracil (Efudex). All of these tropical remedies require several weeks of application for treatment to work and they tend to cause a huge inflammatory skin response — meaning compliance becomes an issue and patients do not continue through with the treatments, as the side effects are often worse than the original lesion.
But in 2010 some new research out of Australia highlighted a new topical option with huge promise. At the University of Western Australia a team of scientists studied the anti-tumour effects of Tea Tree Oil when applied sub cutaneous and in mouse models the Tea Tree Oil was found to be able to regress melanoma
In 2017 a further review of Tea Tree Oil (TTO) by Rashana Singh and Tanya Gupta at Jaypee Institute of technology in India highlights the vast array of medicinal properties of Tea Tree Oil, including the anti-cancer activity of the active ingredient in TTO, known as Terpinene-4-ol.
From 2012 to 2017 a series of studies were also undertaken at the University of Kentucky (USA), headed by Professor Don Cohen, which further validated the earlier work undertaken in Australia and also tested a fully formulated product utilising Tea Tree Oil to regress Actinic Keratosis.
The product, marketed under the brand name of ZenaDerm, is a topical cream utilising the active ingredient found in Tea Tree Oil, known as terpinen-4-ol.
Although the exact mode of action is unknown for Tea Tree Oil, one study showed that TTO appeared to stimulate an immune response (i.e. neutrophils, dendritic, and T Cells) and anti-tumor efficacy is facilitated by a direct effect on subcutaneous AE17 tumor cells in vivo Ireland et al. (2012)
Whatever the mode of action, several clinical trials support the efficacy of Tea Tree Oil and its active components, including terpinen-4-ol, for the treatment of AK lesions. While most lab models used a solvent called DMSO to improve penetration of the Tea Tree Oil, this causes irritation similar to other topical treatments, such as Efudex and Aldara, but the manufacturers of ZenaDerm have been able to overcome those laboratory issues by the clever use of Vanilla extracts as the coupling agent in their formula. Vanilla is a natural vasodilator and carries the Tea Tree Oil below the skin, where it needs to be, to penetrate the lesion and work quickly to regress it.
Interestingly the dermal irritation scores on the ZenaDerm product were extremely low, showing no irritation to human skin under normal use conditions. Further work on AK continues but ZenaDerm has been released commercially in 2019 and is available online in Australia and in the USA is sold online and through dermatologists.