– Not all honeys are created equal, Theodore Rosen, MD, said at the meeting provided by Global Academy for Medical Education.

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Kanuka (Kunzea ericoides) is shown in bloom.

“It seems that kanuka is the new manuka,” said Dr. Rosen, professor of dermatology at Baylor College of Medicine, Houston. These lesser-known New Zealand bush honeys may be something to watch because research and case reports continue to provide intriguing hints of how these honeys exert their immunomodulatory effects on skin, he commented, describing a recent case report describing the elimination of a large, long-standing actinic keratosis (AK) with application of kanuka honey.

Manuka (Leptospermum scoparium) is a large bush native to both Australia and New Zealand. Kanuka (Kunzea ericoides) is quite similar in size and appearance, but native only to New Zealand. Honey made from the flowers of these bushes possesses some unique properties that make it an attractive addition to wound healing regimens, according to a 2014 study (Int J Gen Med. 2014;7:149-58).

The study examined samples of manuka, kanuka, a manuka/kanuka blend, and clover honey. The investigators found that kanuka honey, and to a lesser extent manuka honey, exerted a potent anti-inflammatory effect in human embryonic kidney cells. The honeys interfered with toll-like receptor 1 and 2 signaling, which would reduce the production of proinflammatory cytokines.

Kanuka’s potency seems directly related to its unusually high level of arabinogalactan, according to Saras Mane, MD, primary author of the AK case report (Case Rep Dermatol Med. 2018 May 31;2018:4628971). Dr. Mane is with the Medical Research Institute of New Zealand in Wellington.

Saras Mane, MD

The actinic keratosis on the patient's hand at basline (left), before topical application of the kanuka honey ointment. The actinic keratosis on the patient's hand (right) after three months of applying a kanuka honey ointment.

“The immunomodulatory properties of kanuka honey in particular are thought to be more potent than other New Zealand honeys due to the relatively high concentrations of arabinogalactan proteins present,” Dr. Mane and his coauthors wrote in the case report. “These proteins have been shown to stimulate release of TNF-alpha from monocytic cell lines in vitro.”

The report involved a 66-year-old man who was enrolled in a randomized trial of a commercialized medical-grade kanuka honey ointment (Honevo, 90% kanuka honey, 10% glycerin; Honeylab NZ) for rosacea.

The patient also had multiple AKs, including a raised, crusted, scaly lesion measuring 20 mm by 21 mm with marginal erythema on the back of one hand. The lesion had been present and dormant for a number of years, but it had recently begun to grow.

Dr. Theodore Rosen

“This gentleman decided he’d just try the honey on his AK, too,” Dr. Rosen said. The man reported applying a small amount to the lesion and erythematous area once a day, leaving it on for about 30 to 60 minutes. After 5 days, he stopped because the lesion became tender. During the next two days, the patient reported “picking at” the lesion, which was softening. He repeated this cycle of treatment for 3 months with no other therapy to the lesion.

“The lesion gradually reduced in size with an initial rapid reduction in its dry, crusted nature,” the authors reported. “After 3 months, residual appearance of the lesion was a 20 mm by 17 mm area of pink skin with no elements of hypertrophy, crusting, or loss of skin integrity,” they noted. “At 6 months, there were no signs of recurrence. At 9 months, the appearance of the skin had fully returned to normal. A telephone follow-up was conducted at 2 years after treatment, and the patient reported that his skin in the area was still completely normal and that there were no signs of recurrence.”

Dr. Mane noted that they had only clinical evidence, and no histology of the lesion either before or after its change. “The AK was diagnosed and treated in primary care, where it is not usual for AKs to be biopsied, and the decision to write up the case was made after the course of treatment had finished,” they said.

“Immunomodulatory topical agents are already widely used in the treatment of AK as an immune component is evident in its etiology,” they wrote. “Immunocompromised patients have 250 times the risk of developing an AK than the general population.”

Dr. Rosen said that kanuka honey is also being investigated in psoriasis, eczema, acne, herpes simplex virus, and diaper dermatitis. It is also being studied for rosacea.

Dr. Mane declared no conflicts of interest. Some coauthors disclosed that they have previously received funding from HoneyLab NZ. Dr. Rosen has no commercial interest in HoneyLab.

The meeting was sponsored by Global Academy for Medical Education; Global Academy and this news organization are owned by the same parent company.