Reducing Symptoms Of Seasonal Allergies With Peppermint

Allergies are common, affecting 1 in 4 people in the UK, and can cause frustrating symptoms.¹ Peppermint oil is derived from the peppermint plant, Mentha piperita, and has long been used for its medicinal properties, dating back to the Ancient Egyptians, Romans and Greeks.² Is peppermint oil a potential option for relieving allergic symptoms and providing some relief?

What are allergies?

An allergy occurs when our body encounters a substance that it deems harmful and triggers a response by our immune system. These substances, called allergens, are usually harmless but in certain people can prompt symptoms that range from minor inconveniences to life-threatening conditions.

Allergies can be further classified as either seasonal or perennial. Seasonal allergies tend to occur in certain months of the year, as the prevalence of the allergen increases in the environment. The most common seasonal allergens are:³

• Tree pollen (March/April)
• Grass pollen (June/July)
• Ragweed (Autumn)
• Mould (Autumn)

Perennial allergies occur throughout the year, as the prevalence of the causative allergens is not dependent on the seasons.³ These allergens include:

• Food, e.g. milk, nuts, eggs
• House dust mites
• Animal fur
• Insect bites, e.g. bees, wasps
• Medications

Symptoms of allergies

The symptoms of allergies vary and include:

• Nasal symptoms (allergic rhinitis), e.g. nasal congestion, runny nose, sneezing
• Chest symptoms (asthma), e.g. coughing, wheezing, shortness of breath
• Skin symptoms, e.g. itching, rashes
• Diarrhoea
• Nausea
• Itchy and/or watery eyes

Which allergic symptoms a person experiences depends on the mode of transmission of the causative allergen. Because of the nature of seasonal allergens, their route of transmission is through inhalation and thus inflammation within the nasal tissues leads to the symptoms typically characterised by allergic rhinitis.

A small subset of individuals who suffer from allergies may develop a severe allergic reaction called anaphylaxis. It can be life-threatening, marked by rapidly developing airway and/or breathing and/or circulatory compromise. It is a medical emergency and requires immediate medical attention.⁴ 

It is therefore really important to be familiar with the signs and symptoms of an anaphylactic reaction. Remember ABC:

• Airway problems
  • Do they feel like their tongue or throat is swelling up?
  • Are they having difficulty breathing or swallowing?
  • Does their voice sound hoarse?
  • Is there a high-pitched noise when they breathe in?
• Breathing problems
  • Do they look short of breath?
  • Do they sound wheezy?
  • Is their skin turning pale and blue?
• Circulatory problems
  • Are they pale and clammy?
  • Do they feel faint, dizzy or near collapse?

Any of the above symptoms should be acted on immediately. If the person is known to have severe allergies, they may carry an adrenaline auto-injector that can be used as soon as any of these signs are identified.

The mechanism of an allergic reaction

Our body encounters an allergen in different ways: through inhalation, ingestion or a break in our skin. Regardless of the method, once the allergen enters our body it is met by dendritic cells. These cells form the first line of defence against all potential threats to our body by presenting foreign substances to our immune system. In the event that a substance is not recognised, it is deemed to be a threat and the immune system becomes activated to protect our body from the invasion. This culminates in the production of specialised antibodies, called IgE antibodies, which circulate in our bloodstream. This process is known as sensitisation and ensures the body is primed for its next encounter with the same allergen.

The next time the allergen enters our body, it is detected by the circulating IgE antibodies, which quickly activate mast cells to release inflammatory mediators that trigger allergic symptoms.⁵ This is why symptoms tend to develop quickly following exposure to an allergen.

Histamine is one of the key allergic inflammatory mediators that act on blood vessels in the affected area, causing them to vasodilate, i.e. become leaky. This results in the release of fluid and localised tissue swelling, which is perceived as a runny nose and nasal congestion. Histamine can also act on the surrounding sensory nerves to cause pain and itching.⁶

Conventional allergy treatments

The main strategy, therefore, in treating allergic symptoms is to target the inflammation process that occurs. The National Institute for Health and Care Excellence (NICE) recommends intranasal corticosteroids and antihistamines (oral or intranasal), either alone or in combination.⁷

Steroids have long since been known for their role as an anti-inflammatory medication, and are the most effective at treating allergy symptoms. However, their speed of onset leaves a lot to be desired, ranging from hours to days, with a maximal effect of up to 2 weeks.⁷ Most clinicians will offer intranasal steroids, to avoid the systemic side effects that come with oral preparations. However, both modalities have been proven to be effective in the treatment of allergies.

Antihistamines, on the other hand, whilst not as effective as steroids, work quicker when administered intranasally; with a speed of onset of minutes.⁷

As with most medications, both steroids and antihistamines will have side effects; particularly when taken orally. The persistent use of intranasal steroids can also lead to an increased risk of systemic absorption, such that systemic side effects should also be considered.

Peppermint oil and its potential to treat allergies

Peppermint oil contains several active components, including menthol, menthone and limonene; which in addition to having other beneficial roles, are thought to have antiallergenic properties. Whilst its use, and advocacy for treating allergies, are widespread in the complementary medicine field;² there are limited clinical studies looking into the association between peppermint oil and allergies. What studies there are, are confined to preliminary animal studies. Instead, up until now, the research focus has been on the use of peppermint oil for the treatment of stomach cramps.

One such animal study, involving mice, demonstrated the ability of peppermint to reduce the level of mast cells within the nasal tissues, reduce the production of IgE antibodies and reduce the level of mucus secretion.⁸ Another preliminary study, again in mice, demonstrated that menthone has the potential to reduce allergic airway inflammation.⁹

However, it seems that these promising effects may not extend to humans.

One of the key components of peppermint oil, menthol, has been researched extensively in its role as a decongestant. Many studies have demonstrated that menthol activates a cold receptor found in the skin and mucous membranes, including the nose, to mediate a sensation of increased airflow and tissue cooling; without any tangible structural changes.^10,11 But limonene, another component of peppermint oil, has been associated with anti-inflammatory properties¹². Peppermint oil is also known to be an expectorant that can be used to clear excess mucus from the airways.¹³

Collating all of the above information leads to the conclusion that the jury may still be out on the absolute efficacy of peppermint oil in treating allergies. However, when it comes to symptomatic relief, it may very well be worth a try. Although the evidence shows that it may not effectively tackle the underlying physiology behind the symptoms, some of its key components have been positively associated with alleviating the symptoms themselves. And for a person suffering from allergies, the distinction between the two may be fruitlessly academic.

How to use peppermint oil?

If you do decide to try peppermint oil as a means of reducing your allergic symptoms, the best way to do so is through inhalation. Place 3-4 drops of oil into a bowl of hot water.¹⁴

Is peppermint oil safe?

Whilst rare, side effects of peppermint oil can occur. Its inhalation can cause apnoea and airway spasms in susceptible individuals. Its use is also contraindicated in children under 2 years of age for this very reason.¹⁴

Peppermint oil has also, again rarely, been linked to allergies and anaphylaxis due to some of its active components; most notably menthol and limonene.^15,16

Summary

Allergies are the outcome of exaggerated responses by our body’s immune system to usually harmless substances. The severity of these reactions will vary between individuals, but in some people, can be life-threatening. Seasonal allergies can occur due to environmental triggers such as tree and grass pollen and mould.

Antihistamines and steroids are effective medications that can be used to treat allergies, but as with most medications, they come with side effects. 

Therefore, some people may choose to opt for alternative treatment methods. One such option is peppermint oil, a naturally occurring substance that has the potential to reduce the annoying symptoms of allergies. Whilst more research is needed, preliminary studies are promising. However, it should be noted that peppermint oil can cause allergic responses in susceptible individuals.