Honey in Wound Care
The use of medical honey in wound care has regained increased attention worldwide. With the concerns about antibiotic resistance, there is much focus on antibacterial wound products like honey. The use of honey in wound care has a high "acceptance" in patients, probably because it is seen as a gentle and natural treatment.
Medical honey comes in many different variations - as gels, creams, ointments, contact layers, foams, or alginates impregnated with honey. You may ask yourself - is there a big difference between regular honey and medical honey? We will answer that question shortly.
The indication for using honey products in wound care is primarily when we suspect a high bacterial burden in the wound. We can also use it in a prophylactic manner- that is, to prevent bacteria from becoming a burden in the wound. However, honey performs also very well in wounds without any bacterial burden. The osmotic- and pH-lowering effect of honey positively stimulates the wound. Honey has, in many ways, all the attributes we are looking for in a wound care product. It is antimicrobial and provides an ideal moist environment with a suitable pH for cells to thrive. It appears to have an anti-inflammatory effect that can sometimes also lead to a reduction of pain. Honey often also reduces the smell in necrotic wounds. We have recently ( 2021) done an in-vitro trial at our clinic, where we compared the antibacterial effect of honey on three different bacterial strains ( Pseudomonas aeruginosa, staphylococcus aureus, and Enterococcus fecalis). The bacteria were incubated on blood agar plates, and the antibacterial products were tested on these heavily colonized plates. Medical honey outperformed all other products ( super-oxidized water, hyaluronic acid- iodine gel, vinegar hydrogel) regarding how long the antibacterial effect lasted. After three days, only the plates with honey still showed an antibacterial effect. These results are not published yet.
From our own experiences, we see that honey does a good job of initiating and supporting the autolytic debridement processes in many types of wounds. We also use it when we want to "kick-start" a wound where progress has stalled for one reason or another. We have seen wounds where honey has led to rapid improvements and at the same time other wounds where honey has not led to any significant change in the wound. This is the way it is with most other dressings we use. There are no single dressings that perform perfectly every time, and we do not always understand the mechanisms behind this phenomenon.
You can basically use honey in most wounds. There is little you can do wrong with this product group. Perhaps the most common mistake is to have too long dressing change intervals initially. Especially in the start when using honey products, many wounds will produce more exudate. This is due to the sugar content of honey that draws water from the wound bed. The look of the wound at the first dressing change can deter both the caregiver and the patient when using honey. The honey has usually turned into a grayish liquid, and there may be increased maceration of the wound edges. Instead of giving up on the honey, try changing the dressing more often, for example, daily. Use a barrier product around the skin edges when using honey. You may want to try another secondary dressing to see if that gives you better results. Our point is- when used correctly, honey can outperform many other dressing types.
We generally do not use honey dressing when we have wounds with much exudate, as honey can lead to even more exudate. For this reason, we seldomly use it in venous ulcers because these tend to have a fair amount of exudate. Of course, you can use honey in venous ulcers too, but preferably first after a while, when compression therapy has led to better exudate control.
We know that many studies show that honey can positively affect diabetic foot ulcers. We have had mixed results with honey in diabetic foot ulcers ourselves; sometimes, we have seen severe maceration even when protecting the peri-wound area and increasing dressing change frequency. This is not to say that you should not use honey in diabetic foot ulcers. We are saying that you have to be vigilant when using honey in these patients and perform frequent dressing changes at the start.
Did you know that some patients actually can have a honey allergy? According to a literature search, this is a rare phenomenon. If you suspect that your patient can have an allergic reaction to a honey product, you obviously have to stop using honey products. Where available, the patient should also be referred for dermatological testing (allergy tests) as this can have consequences for what type of wound care products the patient can tolerate. In most settings in Africa, dermatological testing is not a realistic alternative.
How does honey work in a wound?
Because of the high sugar content, honey exerts a strong osmotic effect on cells, which can stimulate healing processes. Since honey also has a high water content, it provides a perfect moist environment ideal for wound healing. This environment is ideal for autolytic processes that help break down necrotic tissues.
Honey has broad-spectrum antimicrobial properties, and it inhibits many types of pathogenic bacteria and fungi, protozoans, and even some viruses. When we use honey in a wound in a prophylactic manner, we may be able to reduce the use of antibiotics in wound care.
The primary antimicrobial effect is due to the high sugar concentration in honey. 95-99% of honey is sugar (mainly fructose and glucose). The sugar binds water from the wound, and this lack of "free" water inhibits bacterial growth.
Even though honey tastes sweet, it is actually an acidic product and has a pH of between 3,2-4,5. The low pH also inhibits many types of bacteria and is ideal for stimulating healing processes in the wound.
When honey comes into contact with wound exudate, hydrogen peroxide is produced via an enzymatic reaction (glucose oxidation). Hydrogen peroxide also has an antimicrobial effect. How much hydrogen peroxide is produced varies significantly between different types of honey.
Medical honey versus regular household honey
You may be aware that most types of medical honey are produced from a honey type called Manuka honey. What makes Manuka honey so unique? One thing is that medical honey is sterilized, but is the effect on the wound really better than honey from the highlands in Zimbabwe or Acacia honey from Ghana? Is it actually safe to use regular household honey in a wound?
Our literature search has not shown a single documented case of wound infection from the use of regular household honey. So yes, it is assumed to be safe to use regular honey in wounds. In theory, however, there can be a risk of infection. It sounds paradoxical, but some pathogenic microbes can actually survive in honey even though it has a high antibacterial effect. Contamination can come from the intestinal flora of the bees or their larvae, from pollen, and secondary after the harvesting ( dust, contaminated containers, contact with skin). Most bacteria cannot reproduce in honey, but bacteria and some other microorganisms can make spores and survive in honey in this form. Several bacteria like bacillus-, clostridium-, enterobacter-, e.coli- and Pseudomonas strains can produce such spores. Different types of fungus can also produce spores.
Some studies have shown bacteria like Clostridium ramosum and Staphylococcus warneri in regular household honey. These bacteria could, in theory, colonize a wound and cause an infection. Again, the chances of this happening are probably minimal.
As you probably know, honey may contain spores from Clostridium botulinum. It is, therefore, an international recommendation that honey should not be given to children as food before they are at least one year of age. It does not help to "sterilize" the honey by heating it. Firstly, the spores of most bacteria can withstand high temperatures. In addition, the heat will destroy the beneficial properties of the honey, which makes it attractive for use in wound care. For this reason, medical honey is sterilized using gamma radiation.
What about the antimicrobial effect of honey? Are there really any differences between different types of honey? We have to admit that we thought some years ago that honey is equivalent to honey, i.e., that any differences were probably not significant. We were wrong. Depending on the environment where the bees live, honey can vary quite a lot concerning sugar content, pH, how much hydrogen peroxide it produces in the wound, and whether it contains other antimicrobial substances. Many studies on honey are unfortunately paid for by companies producing medical honey, so we have to interpret the results with care. But even independent studies have shown some differences concerning the antimicrobial effect of various types of honey. Whether these differences translate into significant differences in an actual wound is uncertain. In a Norwegian study ( Merckol, 2009), the antibacterial effects of sterile medical honey from New Zealand and Norwegian Woodland Honey were compared. Both types of honey had comparable antibacterial properties, including methicillin-resistant staphylococcal strains (MRSA).
What is all the hype about Manuka honey? Without a doubt, honey derived from the pollen of certain plants contains substances that have antimicrobial properties on their own. In this way, they may give a synergistic effect to honeys own antimicrobial properties. Manuka honey is derived from the Manuka plant ( Leptospermum scoparium). It grows as a bush or little tree on the east coast of Australia, in New Zealand and Tasmania. The plant is used to make an essential oil with antibacterial properties. This oil is sometimes referred to as tea-tree oil. However, the true tea-tree oil is usually derived from another member of the myrtle family of shrubs (this was a digression just to get our facts right).
It wasn't until around the 90's that manuka honey started to be marketed as a wound care product. A lot has happened since then. Advertisement- and marketing campaigns have been, without a doubt, successful, and manuka honey has dominated the medical honey market ever since. Manuka honey is also sold as regular food honey, sometimes at hugely inflated prices. Yes, Manuka honey has some properties which differentiate it from other types of honey. Is the hype about Manuka honey justified? Probably not. One of the substances isolated in Manuka honey is called methylglyoxal. This substance is seen as crucial for the stable antimicrobial effect of Manuka honey. Methylglyoxal can be found in most types of honey but usually in lower concentrations.
Interestingly, methylglyoxal levels actually are not very high in fresh Manuka honey. Only when Manuka honey is stored for some time at around 37 °C does the amount of methylglyoxal increase. There are probably other types of honey worldwide that also have excellent antibacterial properties and high concentrations of methylglyoxal, but most types of honey have not been adequately studied. We have noticed that several companies now aim to compete for the honey market in wound care and are starting to perform studies on other honey from around the world. However, Manuka honey remains the medical-grade honey that has the most documentation.
There is no doubt that honey can be an excellent alternative to other dressings in wound care. Honey is used as traditional medicine in wound care in many countries worldwide. Even if most types of food-grade honey do not have any documentation about their individual antimicrobial properties, we can assume that they all inhibit bacteria to some degree and that the stimulating effect of wounds is similar to medical-grade honey.
Medical honey is expensive, and in most areas of Africa, it is not a realistic alternative because of the price. Therefore regular household honey is used here. Since there is no documentation that regular food-grade honey poses any real threat of infection, we can recommend this practice as long as there are no other alternatives. However, it is advised that honey for wound care is purchased in shops instead of from local gatherers. We are concerned that honey produced by individuals can be stored in contaminated containers. In most African countries, beekeepers selling to shops are usually registered and adhere to specific hygiene regulations.
In the western world, however, things are more complicated. For example, there are rigid regulations as to what products can be used in the public health sector. Also, honey products must be registered to be used in wound care, and formally only medical-grade honey is accepted. For example, at our clinic, we are not allowed to use food-grade honey in wound care. However, the patient can use food-grade honey if they wish to do so. In this situation, we are obliged to inform the patient that regular honey is non-sterile and that theoretically, spores could be transferred into the wound and that the patient does this at their own risk.
The following are general recommendations for the use of honey in wounds:
Honey is contraindicated when the patient has a known honey allergy
Rarely some patients may feel a stinging sensation when honey is applied to a wound. This is usually only temporary and passes after about half an hour.
Honey paste or cream is applied directly into the wound and covered with a secondary dressing. Often polyurethane foam dressing are used for this. If there is more exudate, a superabsorbent dressing may be appropriate. If you have few resources, regular cotton pads may have to be used as a secondary dressing. Be aware that these may absorb more of the honey and that honey may have to be applied more often.
Use appropriate barrier products to protect the peri-wound area from maceration.
We recommend changing the dressing once daily at the start, sometimes several times daily if there is much exudate. In the course of the treatment, the amount of exudate usually decreases, and longer shift intervals can be used, sometimes as long as five days.
Usually, within about 14 days, we expect to see a definite improvement in the wound. During the first week, the wound is typically busy cleaning up. After that, granulations slowly set in. Of course, this is a generalization and will depend greatly on what type of wound we are dealing with.
Honey is not a substitute for sharp debridement when there is much necrosis or if there are signs of serious infection.
Figure 1 The range of medical honey for wound care has become quite diverse and confusing. There are contact layers impregnated with honey, foams with honey, and alginates with honey. Some products contain 100% honey; others may contain, for example, only 30% honey. Some contain a mixture of honey and, for instance, cod-liver oil. If you are new to medical honey in wound care, we advise you to start using products containing 100% honey in a tube.
Video 1 Example of using one type of medical-grade honey, Medihoney Apinate. The video illustrates that it is wise to use some time to check how a particular product is to be used so that we can eliminate common mistakes.