Cluster headaches are a rare form of headaches that are marked by a debilitating one-sided pain. Cluster headaches derive their name from their occurrence in groups (clusters). They are also known as “suicide headaches,” owing to their reputation of rendering the suffering individual drained and exhausted after an attack.
However, neurologists like who is also certified in Clinical Neurophysiology, and has been working in the field for nearly two decades, consider this condition to be largely “non-threatening” as it does not result in any long-term health complications.
Cluster headaches involve the trigeminal nerve of the face. The hallmark symptom of a cluster headache is a deep, burning pain around on eye (the site of the trigeminal nerve). This period of intense pain is the attack that can occur several times throughout the day/week(s)/month(s), hence the name cluster.
Cluster headaches tend to occur five to six times more in men than women and are most common between the ages of 20 and 40.
Cluster headaches affect approximately 0.1 percent of the population. These headaches can be familial and have an autosomal dominant genetic basis in some cases.
This claim is further supported by Dr. Bernheimer, who has served as Medical Director of the Stroke Program at Mercy Medical Center and Greater Baltimore Medical Center. According to Dr. Bernheimer, “There is a genetic component to cluster headache, and often there will be a family history of migraine as well.”
Cluster headaches are different than migraines both in the intensity of symptoms and frequency of occurrences.
In the words of Dr. Bernheimer, “I would not say cluster headaches are necessarily worse (or better) than migraine. Just different: different pattern of occurrence, slightly different treatment, and cluster headaches are less common in general and more common in men than women, whereas migraines are much more common in general but affect twice as many women as men.”
There is no concrete evidence regarding the exact cause of cluster headaches, making the complete treatment or prevention of a cluster headache all the more difficult. There is literature that suggests a role of a portion of the hypothalamus as a cause of cluster headaches. Certain substances, habits, and environments have also been known to trigger cluster headaches.
Although over-the-counter painkillers are often ineffective in ameliorating the intense pain of a cluster headache, one can avert or reduce its occurrence by using prescribed medications, abstaining from and avoiding predictable triggers, and trying alternative therapies.
Let’s take a look at the various aspects of a cluster headache.
Pattern of Attacks
Cluster headaches may follow one particular pattern in each individual. It may awaken a person in the middle of the night. Several people may experience more than a single attack a day, about the same times every day. These headaches may also occur at the same time every year, especially during the months of autumn and spring. The pattern differs from person to person.
Each attack may last for several days, weeks, or months before the symptoms may reduce or disappear. This period where the individual may experience no symptoms at all can extend from a few months to years prior to the onset of a cluster headache.
A small 10–20 percent of people may experience chronic cluster headaches that may last for a lifetime or may take a month or less for the symptoms to subside or resolve.
Dr. James Bernheimer throws further light on the pathology of cluster headaches. “Each headache usually lasts no more than 30-60 minutes, but they may recur several times over the course of a day, or commonly at night. However, a patient may have a cluster of multiple brief headaches a day, daily, for up to several weeks followed by intervals of being completely headache free”, as per the doctor.
What Can Trigger a Cluster Headache?
The primary reason behind a cluster headache is not yet known. It is suggested that it is an outcome of a sudden release of biochemical compounds such as serotonin and histamines that act as an irritant/trigger on the trigeminal nerve.
The common triggers include:
- Physical activity, especially exercising in hot weather
- Intense light, including sunlight accompanied by heat/high temperature
- High altitudes during air travel or trekking
- Certain foods such as shellfish, smoked fish, and canned meats
- Certain medications including nitroglycerin
Dr. Bernheimer dispels any doubts regarding the causative relation between eye strain and the onset of cluster headaches. According to him, “Eye strain is not recognized as a possible trigger for cluster headaches.”
Signs of a Cluster Headache
The signs and associated symptoms that are indicative of a cluster headache include:
- Severe excruciating pain around one eye, radiating to the forehead, cheeks, temples, and upper gum on the same side of the face.
- Nasal congestion and/or rhinorrhea.
- Agitation and restlessness.
- Unilateral sweating on the forehead.
- Drilling pain that may be prominent around one eye, which may become watery or bloodshot with drooping eyelids.
- The affected side of the face may be reddened or flushed.
- Steady painful attacks one to three times a day, lasting for 15–180 minutes. Attacks may occur consecutively for 6-8 weeks.
- Photophobia may occur.
Diagnosis of a Cluster Headache
Your doctor will diagnose your case based on the pain, pattern of attacks, and symptoms you have been experiencing during a headache. He will physically examine your pupils and eyelids to check if they appear to be different than normal.
Keeping a track of your triggers can help you identify them and steer clear of an attack in the future. It is advised to keep a log book and write down the details pertaining to the attacks you experience, including the severity, frequency, and type of pain and anything that might be a possible trigger to your headache episode.
Standard Treatment for a Cluster Headache
Cluster headaches cannot be resolved with over-the-counter painkillers.
You can considerably reduce your chances of having a cluster headache episode by avoiding triggers such as alcohol, stress, high altitude, and insufficient sleep.
Your doctor is likely to recommend the following medications or therapies for you to survive through a cluster headache:
- Sumatriptan injections – These work by constricting the blood vessels in the brain that help to block the transit of pain signals. Also used to treat migraines, sumatriptan injections are administered into the skin of the upper arm or thigh, but never into a muscle or vein. Always get these injections under the supervision of a doctor.
- Oxygen therapy – Inhaling pure oxygen can help bring down a cluster headache. A face mask is used to deliver at least 7–10 liters per minute of oxygen for a short period of 15 minutes. You and your doctor will have to sign a Home Oxygen Order Form (HOOF) if you want a small unit at your house. NOTE: Oxygen in such high concentrations is toxic to the lungs and can scar lung tissue. It must be used for short periods of time (<15 minutes) only once or twice in a day. In fact, Dr. Bernheimer is of the opinion, “The best treatment for quick relief from cluster headaches is oxygen, which is usually administered by a nasal cannula.”
- Nasal sprays – Nasal sprays such as lidocaine may provide relief from acute pain induced by a cluster headache.
- Biofeedback technique – Biofeedback has been used as a therapy to reduce the frequency and severity of headaches with a 45–60 percent positive outcome. Its efficacy is backed with evidence from researches for the past 25 years. This alternative therapy is targeted at controlling involuntary body functions such as blood pressure, heart rate, muscle tension, and brainwave activity.
- When combined with conventional medications, biofeedback can help control a headache.
- It includes relaxation techniques such as meditation, yoga, relaxation exercises, and focus and concentration imagery exercises.
- For most patients suffering from headaches, a combination of electromyographic (EMG) feedback and temperature feedback is preferred.
Tips to Manage a Cluster Headache
Besides the standard prescribed medications, you can incorporate certain changes in your lifestyle, diet, and daily routine to overcome a cluster headache.
1. Apply a Cold/Hot Compress
An easy solution to your cluster headache is a cold compress. The cold temperature of the ice has a numbing effect on the pain.
- Take a bag of frozen vegetables or wrap some ice cubes in a washcloth. Apply this on the back of your neck. Alternatively, you can dip a washcloth in cold water and place it over your head for 5 minutes. Repeat the application several times as needed.
Heat will help relax muscle tension and relieve you from the pain of a pulsating headache.
- Take a hot water shower and let the water drip on your neck. This will help relax your neck muscles.
- Keep a cotton cloth on the back of your neck and place a hot water bag over it. Keep it on for 10–15 minutes.
2. Consider Acupressure
Acupressure is a widely used technique in Chinese medicine.
Pressure is applied on specific points in the fingers and hands, called acupoints. Stimulating these points with pressure can help reduce pain and several other health ailments.
A 2014 study published in Pain Management Nursing corroborated the use of acupressure as an alternative therapy for people suffering from the pain of chronic headache and other traumatic pains.
Another 2010 study published in the American Journal of Chinese Medicine highlighted the effectiveness of acupressure treatment in reducing chronic headache compared with a muscle relaxant treatment. The study was conducted for a period of 1 month and the commonly used acupoints to relieve pressure were BL2, GV20, GB20, TH21, and GB5.
Make sure that acupressure is done by an expert or under the supervision of a professional.
3. Get a Massage
A gentle head massage can help relax your headache by promoting serotonin activity and triggering the serotonin receptors to curtail the frequency and symptoms of a headache.
It can also help relieve a headache by blocking the signals for the headache-induced pain sent to the brain.
- Using your first two fingers, massage your head gently in a circular motion. Properly pressing the pain-relieving pressure points lying at the base of the skull, in the corner of the eyes, and in between the eyebrows can help provide some relief from the pain.
- Alternatively, you can prepare a massage oil by mixing 2 tablespoons of hot sesame oil and ½ teaspoon each of cardamom powder and cinnamon powder. Use this mixture to massage your forehead. Leave the oil mixture on for a few hours.
4. Go for a Chiropractic Therapy
Cluster headaches can be relieved by chiropractic care by tending to the regions from where the headache is stemming from.
Chiropractic therapy is a treatment wherein a practitioner helps relieve the tension around the bones, joints, and muscles of the cervical area by making use of his hands.
The chiropractor will use different techniques to relieve the pain. These include:
- Stretching or pulling the muscles in varied directions
- Sharp short thrusting movements
- Moving the joints in different positions
- Applying force in the spinal region
5. Give Essential Oils a Thought
Essential oils are accredited with antispasmodic and anti-inflammatory properties that can have a soothing effect on your nerves and help calm your headache.
5.1. Marjoram Oil
The fresh and dried leaves of the marjoram plant (Origanum majorana) yield an essential oil that harbors analgesic properties. The oil, when massaged on to the temples, has an ability to recirculate the flow of blood.
It also relaxes and calms the mind and body and helps bust stress and anxiety.
- Add it to your bath water, or use it to massage your head.
5.2. Rosemary Oil
Rosemary oil contains soothing and anti-inflammatory properties owing to its primary bioactive ingredient – rosmarinic acid. These properties can help relieve a headache.
A 2013 study published in Food Chemistry stated that rosemary has anti-inflammatory and pain-relieving properties, making it a suitable choice to treat headaches.
- Mix a few drops of rosemary oil in 1 tablespoon of carrier oil and use the oil mixture to massage your temples.
5.3. Peppermint Oil
Peppermint oil boasts a rich composition of menthol that is known to have an analgesic effect on headaches. It works by opening up the blocked blood vessels that are known to cause a cluster headache.
A 2016 study highlighted that a solution of 10 percent peppermint oil in ethanol can effectively treat headache in children over 6 years old as well as in adults.
- Add 3 drops of peppermint essential oil in 1 tablespoon of almond oil or olive oil. Use this oil mixture to massage your temples.
- You can also put roughly ground peppermint leaves on your forehead.
- Alternatively, do steam inhalation. To a small pan of boiling water, add a few drops of peppermint essential oil. Inhale the vapors emanating from the pan for a few minutes.
5.4. Lavender Oil
Lavender essential oil is a soothing remedy to relax a cluster headache.
A 2013 study published in Evidence-Based Complementary and Alternative Medicine accredited lavender oil with pain-relieving properties.
- Smear a tissue with a few drops of lavender essential oil. Smell this tissue throughout the day.
- You can also do steam inhalation. To 2 cups of boiling water, add 2 drops of lavender essential oil. Inhale the vapors.
- In 1 tablespoon of a carrier oil such as almond oil or olive oil, add 2–3 drops of lavender essential oil. Use this oil mixture to massage your forehead.
5.5. CBD Oil
Applying CBD oil (Cannabidiol) can influence the vast network of an individual’s endogenous endocannabinoid system to ameliorate many types of headaches, including cluster headaches.
6. Lifestyle Changes
6.1 Drink Adequate Amounts of Water
Drinking little or inadequate amounts of water is associated with headaches. If you have a habit of not drinking an adequate amount of water a day, you might get dehydrated, which can result in a headache.
A 2015 study published in the Journal of Evaluation in Clinical Practice links the role of chronic mild dehydration as a possible trigger for headaches. Such headaches can be prevented by increasing a person’s water intake.
If you have a headache of any sort, be it migraine or a cluster headache, make sure to drink plenty of water.
- Aside from drinking the required 8 glasses of water a day, you can also consume coconut water, lemon water, and ORS to steer clear of dehydration.
- Eat fruits and vegetables that contain a huge percentage of water such as watermelon, spinach, and cucumber, to name a few.
6.2 Avoid Food Triggers
Certain individuals can get a headache by eating certain foods. Once you have identified these food triggers, you can easily avoid their consumption to prevent a headache. Such triggers include:
- Alcoholic drinks
- Artificial sweeteners
- Monosodium glutamate
- Nitrite rich foods in wine, cured meats, aged cheeses, and some medicines
- Caffeine-containing drinks such as tea, coffee, and cola
A lot of people resort to caffeine to tide over a bad episode of migraine, but Dr. Bernheimer says, “I am not sure if caffeine helps the way it can for migraine.”
Several other common foods that can engender a headache in susceptible individuals include dairy products, chocolates, meat, wheat, shellfish, nuts, peanuts, bananas, onions, eggs, and citrus fruits.
6.3. Do Yoga
Yoga is an alternative therapy that is being practiced since ages to manage chronic pain. It is a combination of various postures and deep-breathing exercises that promote the overall health of an individual.
A 2015 study published in the Journal of Physical Therapy Science corroborated that yoga should be used as an adjunct therapy to help provide relief from the frequency and intensity of headaches.
Yoga does not have any side effects as a treatment to relieve headaches. You can include the following simple yoga poses for a few minutes every day to relieve your headache and prevent it from happening:
- Marjariasana (Cat Stretch)
- Paschimottanasana (Two-Legged Forward Bend)
- Adho Mukha Svanasana (Downward-Facing Dog Pose)
- Setu Bandhasana (Bridge Pose)
- Shishuasana (Child’s Pose)
- Padmasana (Lotus Pose)
- Hastapadasana (Standing Forward Bend)
- Shavasana (Corpse Pose)
6.4 Quit Smoking
Smoking can trigger a headache.
Moreover, exposure to secondhand smoke is harmful and can have side effects such as the narrowing of blood vessels and triggering a headache.
Individuals suffering from a cluster headache must stay away from secondhand smoke or give up smoking altogether. Doing so can reduce the occurrence of headaches.
7. Dietary Additions
7.1 Include Magnesium in Your Diet
Magnesium is an essential nutrient that helps regulate various metabolic processes and the nervous system.
The recommended dosage of 300–400 mg/day of magnesium is sufficient for your daily intake.
Magnesium deficiency has been related to headaches and migraines.
According to a 2015 study published in Nutrients, declining magnesium levels can be related to several diseases.
- Enrich your diet with foods rich in magnesium such as sesame seeds, sunflower seeds, almonds, oatmeal, eggs, peanut butter, and milk.
- Magnesium supplements can have side effects on digestion; hence, consult your doctor for approval.
7.2 Take Melatonin
Melatonin is the hormone that helps regulate your sleep cycles and hormonal levels. Sleep hygiene and its disturbance are related to cluster headache initiation and recurrences.
Some studies have also reported that people experiencing cluster headache may have decreased melatonin levels. However, melatonin can help only when it is taken before the cluster headache episode starts.
Melatonin can improve the quality of your sleep. People who experience trouble sleeping are often recommended to take melatonin supplements. It may be useful as an adjuvant treatment for cluster headaches.
As cluster headaches tend to occur at night, a peaceful sleep may help avoid their occurrence.
7.3. Consider Cayenne Pepper/Capsaicin Cream
Cayenne pepper contains a compound called capsaicin that can stimulate the flow of blood and relieve the pain of a headache.
The bioactive capsaicin can also help alleviate cluster headaches by reducing the related inflammation.
- Consider taking capsaicin supplements upon your doctor’s approval.
- Alternatively, you can make a cayenne pepper drink by mixing ½–1 teaspoon of cayenne pepper powder, a few drops of lemon juice, and ½ teaspoon of honey to 1 cup of warm water. Drink this solution to reduce the pain of a cluster headache.
7.4 Consult Your Doctor for Vitamin Supplements
Around 80 percent of people with an existing cluster headache condition experience an increased incidence of cluster headaches as a result of seasonal changes.
Weather changes with decreased sunlight availability can result in decreased synthesis of vitamin D. Researchers have proposed that depleted levels of vitamin D may play a role in inducing chronic headache, including a cluster headache.
Incorporating a high dose of vitamin B2 in the diet has been reported to reduce the incidence of headaches. Administering 500 mg of vitamin B2 every day for a month has been reported to keep away headaches.
- Include foods that are rich in vitamin D including milk, eggs, and fish such as tuna, salmon, and mackerel.
- Eat foods rich in vitamin B2, including beans, seeds, nuts, organ meats, legumes, and green leafy vegetables.
- Alternatively, keep a check on your vitamin D and vitamin B levels. Low levels of these vitamins can be tended to with supplements approved by your doctor.
7.5 Consume Psilocybin Mushrooms
Psilocybin mushrooms can help lessen the intensity and even wipe a cluster headache for weeks to months.
The positive effect of psychedelics, such as psilocybin mushrooms, on people suffering from a cluster headache is quite clear.
Psilocybin mushrooms act as a hallucinogen and it may help treat a cluster headache. However, do not consume them in excessive amounts and avoid them if you suffer from a mushroom allergy.
There are several remedies that have not been researched enough to be backed by evidence but do require a mention because of their popularity among people as a solution to their health conditions.
Although medical doctors do not appreciate the use of the below-listed options very much, they have been used immensely as an old wives’ remedy to calm an existing headache and stop a cluster headache in its tracks.
1. Inhale the Steam of Apple Cider Vinegar
Apple cider vinegar has been used for centuries for its varied health benefits.
You can calm your throbbing headache by inhaling the vapors of apple cider vinegar.
- Fill half a bowl with boiling water and add ¼ cup of apple cider vinegar to it.
- Use a towel to cover your head, lean over the bowl, and inhale the vapors by taking deep breaths. Make sure to keep your face at a safe distance to prevent burns.
- Do this for 5–10 minutes.
2. Apply a Paste of Sandalwood
Sandalwood paste has been used as an age-old remedy to help calm a cluster headache. It can help lessen headache pain by soothing the tensed nerve endings in the optical region.
- Using a little water and ½ teaspoon of sandalwood powder, make a paste. Apply a thin layer of this paste on your forehead. Keep it on for 20 minutes before rinsing it off with cold water.
3. Drink a Cup of Herbal Tea
Chamomile has anti-inflammatory, antispasmodic, and soothing properties that help relieve a headache. Regularly drinking chamomile tea can also help prevent the problem.
- Steep 2–3 teaspoons of dried chamomile flowers in 1 cup of hot water for a few minutes. You can also add some lemon juice and honey. Strain the liquid and drink this tea three or four times a day for relief from migraine symptoms.
- Another option is to steep equal quantities of chamomile, horehound, and meadowsweet in 1 cup of hot water for at least 5 minutes. Strain the liquid and drink it. Repeat as needed.
Ginger contains bioactive compounds called gingerols. These have potential anti-inflammatory and antioxidant properties that have a therapeutic effect on pain.
Ginger can help alleviate pain and nausea, which are the signs of an impending cluster headache.
- Drink ginger tea two times a day to help reduce the symptoms of a cluster headache.
Types of Cluster Headaches
Cluster headaches can be categorized into two distinct types depending on the pattern:
- Episodic cluster headaches – These are marked by sudden attacks that last for short periods of time, ranging from 15 minutes to 3 hours. Although these attacks have a short duration, the frequency might range from 1–8 attacks a day, lasting for weeks to months. The headaches can be predicted by keeping in mind the time when the headache usually strikes. Each attack may be separated by a symptom-free period.
- Chronic cluster headaches – These headaches are chronic and are marked by long durations of severe headache. The individual suffers from a continuous blow of cluster headaches without any symptom-free periods in most cases. In some cases, the symptom-free periods are very short, lasting for less than 1 month in a 1-year time span.
When to See a Doctor
Seek immediate medical help when you experience the following warning signs:
- Changes in vision
- Numbness or inability to move
- Protracted nausea or vomiting
- Increased frequency, duration, and severity of the cluster headaches
Although cluster headaches are incurable per se, you can take measures to reduce the associated discomfort and prevent their recurrence.
It is advised to keep tabs on the triggers and be mindful of the symptoms.
Aside from the conventional medications prescribed by your doctor, develop healthy habits, follow alternative therapies, get a massage, and incorporate changes in your diet to curtail the discomfort and severity of a cluster headache.
Expert Answers (Q&A)
Answered by Dr. Ajeet Sodhi, MD (Neurologist)
How long does a cluster headache normally last?
Cluster headache is one of the most painfully severe form of headaches, which can last for anywhere between 10 minutes to several hours.
What are the most common triggers for cluster headaches?
Common triggers for cluster headaches include alcohol, certain vasodilating medications such as nitroglycerin, and exposure to tobacco smoke.
Can cluster headaches lead to brain damage?
Cluster headaches are not damaging to the brain. However, they are typically among the worst headache pain syndromes that exist, and for this reason, are often referred to as “suicide headaches.”
Can caffeine help relieve a cluster headache?
Caffeine can be helpful for migraines but is generally not useful for cluster headaches.
Please provide some important tips to remember when suffering from cluster headaches.
Cluster headaches do have some treatments available. It is important to seek a neurologist skilled in headache treatments. Cluster headache sufferers often go for extended periods without a confirmed diagnosis, which can lead to needless suffering. Avoiding triggers is also important.
About Dr. Ajeet Sodhi, MD: Dr. Sodhi is the Director of Neuro Critical Care at California Institute of Neuroscience. He trained in Neurology after graduating from the Medical College of Virginia and further specialized in Stroke and Vascular disease, Neurocritical Care, and Neurointerventional Endovascular Surgery.
In addition to his neurologic subspeciality training, Dr. Sodhi has a significant interest in the new field of neuroregeneration and unorthodox therapies, especially for conditions in which current treatments are limited.
- Wei DY-T, Ong JJY. Cluster headache: Epidemiology, pathophysiology, clinical features, and diagnosis. annals of indian academy of neurology. http://www.annalsofian.org/article.asp?issn=0972-2327;year=2018;volume=21;issue=5;spage=3;epage=8;aulast=Wei. Published 2018.
- Chen Y-W, Wang H-H. The effectiveness of acupressure on relieving pain: a systematic review. Pain management nursing : official journal of the American Society of Pain Management Nurses. https://www.ncbi.nlm.nih.gov/pubmed/23415783. Published June 2014.
- Hsieh LL-C, Liou H-H, Lee L-H, Chen TH-H, Yen AM-F. Effect of acupressure and trigger points in treating headache: a randomized controlled trial. The American journal of Chinese medicine. https://www.ncbi.nlm.nih.gov/pubmed/20128040. Published 2010.
- Calandre EP, Hidalgo J, Garcia-Leiva JM, Rico-Villademoros F, Delgado-Rodriguez A. Myofascial trigger points in cluster headache patients: a case series. Head & face medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2631448/.
- West J, Phillips RB. Chiropractic management of a patient with persistent headache. Journal of chiropractic medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3838720/. Published December 2013.
- Barloese M, Jennum P, Knudsen S, Jensen R. Cluster headache and sleep, is there a connection? A review. Cephalalgia: an international journal of headache. https://www.ncbi.nlm.nih.gov/pubmed/22407656. Published April 2012.
- Kim S-D. Effects of yoga exercises for headaches: a systematic review of randomized controlled trials. Journal of physical therapy science. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4540885/. Published July 2015.
- Rossi P, Whelan J, Craven A, Ruiz De La Torre E. What is cluster headache? Fact sheet for patients and their families. A publication to mark Cluster Headache Day 2016. Functional neurology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5115234/.
- Yablon LA. Magnesium in headache. Magnesium in the Central Nervous System [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK507271
- Gelfand AA, Goadsby PJ. The Role of Melatonin in the Treatment of Primary Headache Disorders. Headache. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5012937/. Published September 2016.
- Gooriah R, Buture A, Ahmed F. Evidence-based treatments for cluster headache. Therapeutics and clinical risk management. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646474/. Published November 9, 2015.
- Suppression of LPS-induced inflammatory activities by Rosmarinus officinalis L. Food Chemistry. https://www.sciencedirect.com/science/article/pii/S0308814612013817. Published September 12, 2012.
- Lakhan SE, Sheafer H, Tepper D. The Effectiveness of Aromatherapy in Reducing Pain: A Systematic Review and Meta-Analysis. Pain research and treatment. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5192342/. Published 2016
- Suppression of LPS-induced inflammatory activities by Rosmarinus officinalis L. Food Chemistry. https://www.sciencedirect.com/science/article/pii/S0308814612013817. Published September 12, 2012.
- Göbel H, Heinze A, Heinze-Kuhn K, Göbel A, Göbel C. Peppermint oil in the acute treatment of tension-type headache. Schmerz (Berlin, Germany). https://www.ncbi.nlm.nih.gov/pubmed/27106030. Published June 2016.
- Koulivand PH, Khaleghi Ghadiri M, Gorji A. Lavender and the nervous system. Evidence-based complementary and alternative medicine: eCAM. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3612440/. Published 2013.
- Jong-Hee Sohn M-KC. Vitamin D deficiency in patients with cluster headache: a preliminary study. The Journal of Headache and Pain. https://thejournalofheadacheandpain.biomedcentral.com/articles/10.1186/s10194-018-0886-7. Published July 17, 2018.
- Andeon M, Peon M, Kjellgren A. Psychoactive substances as a last resort-a qualitative study of self-treatment of migraine and cluster headaches. Harm reduction journal. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5584001/. Published September 5, 2017.
- Bhargava A, Pujar GS, Banakar BF, Shubhakaran K, Kasundra G, Bhushan B. Study of cluster headache: A hospital-based study. Journal of neurosciences in rural practice. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4173234/. Published 2014.
- Lochte BC, Beletsky A, Samuel NK, Grant I. The Use of Cannabis for Headache Disorders. Cannabis and cannabinoid research. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5436334/. Published April 1, 2017.