When most people think of a metal allergy, nickel is usually first in mind. A ubiquitous metal, like iron, is surely much safer and allergy-free, right? Otherwise why else would it be as common as it is if people had iron allergies?
Well, the science is in and that may not be the case for some people. In this post we’re diving deep into all forms of iron you might come into contact with and iron allergies that may develop as a result. From contact dermatitis to allergies from oral iron and iv iron allergies, we’re diving deep!
We’ll also go into iron allergy symptoms, causes, and treatments.
Keep in mind that if you are experiencing an allergic reaction to any form of iron, consult a medical practitioner immediately! The information shared in this article is general and does not replace personal medical advice offered by your doctor.
Causes of Iron Allergies
Mild causes of iron sensitivities are more common than you might realize. However, severe iron allergies and hypersensitivity reactions are generally quite rare and can present differently in different people. The various causes of a hypersensitivity reaction to iron can include:
- Oral iron supplementation
- Intravenous iron (also known as parenteral iron)
- Iron oxides used in products
- Loose iron particles that come in contact with the skin
- Iron absorbed in food through cast iron cookware
We will dive deep into each of these causes in the article below. Jump to any section using the quick links in the Table of Contents.
Iron Allergy Symptoms
If you have any of the following symptoms after taking iron supplements or coming into contact with iron, seek medical attention as soon as you can.
Common Symptoms
- Back, chest, or muscle pain
- Chills
- Dizzy spells
- Fainting
- Racing heartbeat
- Flushes
- Headache
- Metallic taste
- Hives, red skin, or rash
- Trouble breathing
- Gastrointestinal discomfort
- Swelling of mouth or throat
Less Common Symptoms
- Weakness without feeling dizzy
- General malaise
- Stool with signs of blood
- Double vision
Symptoms of Iron Overdose
- Diarrhea which may contain blood
- Nausea
- Vomiting, may contain blood
- Seizures
- Sharp cramping or stomach pain
- Blue-ish lips and hands
- Unusual tiredness or weakness
Symptoms Which May Not Need Further Treatment
As with any medication, there may be some harmless side effects of iron. These do not usually need medical attention and will usually subside reasonably soon.
Always check with your health care professional if any of the following symptoms last a while or are bothering you greatly after taking a supplement:
- Constipation
- Diarrhea
- Dark urine
- Heartburn
- Mild nausea and/or upset stomach
Allergies to Oral Iron Supplement and Multivitamins
Before we dive into iron supplements, did you know that iron deficiency and anemia have been linked to increased allergies(1)? Especially in women(2).
Iron deficiency also has other negative effects on health including extreme fatigue, weakness in the muscles, pale skin, and more. That’s why the benefits of iron supplementation have been found to greatly outweigh the risks(3).
Iron deficiency anemia, in particular, is a condition treated with oral iron and often with great success. However, allergies to oral iron supplements are also by far the more common forms of iron allergies people experience with up to 70% of patients noting mild gastrointestinal issues at the very least(4).
How to Know If You Are Allergic To Oral Iron
Some people are allergic to oral iron tablets and multivitamins containing iron, while others are allergic to IV iron.
Most people who report allergies to iron supplements usually experience the effects within half an hour. You may experience an iron allergy rash, a feeling of weakness, or extreme tiredness all of a sudden. If so, consult your doctor.
When it comes to such supplements, around 25% of reactions are a direct result of iron allergies(5). If you fall inside this bracket, it is likely your doctor will test for sensitivity to ferric and ferrous iron compounds to determine the extent of your allergy.
Common methods for testing iron allergies include skin prick tests and oral challenges performed with various iron preparations(6). It’s also possible to be desensitized to iron using altered types of oral iron preparations(7). This is a treatment your doctor may give you to avoid repeated iron transfusions and so you can get your iron levels back on track.
IV Iron Allergy: Hypersensitivity and Anaphylactic Reactions to Intravenous Iron
Much like other allergies to iron, IV iron allergies are rare. It’s estimated that 1 in every 5 million doses of IV iron leads to severe allergic reactions and the mortality rate is calculated at only 3 deaths per year in the US(5).
However, due to introducing the iron directly into the bloodstream, the allergy can be life threatening if it does occur.
Due to these risks, iron infusions are only given to patients in a hospital with appropriate equipment and fully trained staff to handle complications. In 2013, the European Medicines Agency Committee for Medicinal Products for Human Use (CHMP) did a thorough investigation of the risks of IV iron and allergies(3).
The report concluded that iron infusions provide more good than harm. It did also recognize that the rare case of hypersensitivity to IV iron was fatal and so new standards and best practices were put in place for proper treatment.
Major Risk Factors For IV Iron Allergies
There have also been more tests and research in this area in recent years and medical scientists have discovered the following major risk factors which may predispose someone to IV iron allergies(8) :
- Previous reactions to iron preparations
- Fast iron infusion rate administered
- Susceptible to other drug allergies
- Severe allergic tendencies
- Systemic inflammatory diseases
- Early pregnancy (as a contraindication)
Information to People
Undergoing IV Iron Injection
Intravenous iron medicines are a valuable treatment for iron deficiencies and anemia. Many patients who are undergoing this treatment are often worried about the risks or hypersensitivity. As mentioned above, it is an extremely rare occurrence.
If you are receiving an iron infusion, know that your doctor will closely monitor you during, and for at least 30 minutes after, the injection.
What To Tell Your Doctor BEFORE Taking Iron Tablets, Capsules or an Iron Infusion
If you have had any reactions to iron supplements or injections in the past, let your doctor know as soon as possible. You should also let your doctor know if you have conditions that affect your immune system like a history of asthma, allergies or inflammatory diseases.
If your doctor perceives you may be at risk, a more cautious approach will likely be taken to desensitize your body to iron. Usually, this involves smaller doses administered over longer periods of time to ensure your safety.
Iron Oxide Allergies
In terms of iron allergies, there’s more to consider! Frequently used to add color to skincare and makeup products, iron oxides provide another cause for concern to anyone with or without diagnosed iron allergies.
We wouldn’t consider it a pure iron allergy as compounds like nickel are a natural part of iron oxides and cannot be avoided. Nickel allergies account for the vast majority of allergies to metal.
With that being said, however, nickel allergy is not the only reason to be concerned about iron oxides. Exposure to iron oxide fumes and/or gas can cause several health issues which can spell all kinds of bad! From acute symptoms like metal fume fever to chronic health effects like discolored eyes and breathing difficulties, to name a few.
Iron oxide nanoparticles have also been linked to damage to neural tissue(9) through iron accumulation and oxidative stress.
All in all, if you are sensitive to iron or nickel and notice iron oxide listed as an ingredient in a product or if you come into contact with it at work in the form of gas or fumes, it may be wise take a wide berth and opt for a safer option. If you experience a reaction to iron oxides, seek medical help as soon as possible.
Iron Allergy Rash and Contact Dermatitis
Iron is famous for being the first metal human beings have worked with. So over the thousands of years iron has been used, we surely would have noticed if something was up when people would touch it. The good news for people with sensitive skin is that contact dermatitis from iron is rare. Like, incredibly rare.
Historically, iron allergies have also been phenomenally low – until supplements came into the picture.
Now, in the small number of cases where people have experienced skin irritation due to iron allergies, there are some things to note. First up, both instances of the first documented accounts of iron-induced contact dermatitis occurred in middle-aged men who were occupationally exposed to large amounts of iron particles in the 1960s and 1970s.
The first was a 44 year old steel welder and the other a 67 year old tool maker(10) who made tools by hand using a lathe and bench. In both instances, the irritation started at their feet because iron particles would settle in their socks and shoes. The irritation did move up and affect other areas of their bodies.
What is interesting to note is that in these cases of iron-induced contact dermatitis, their faces were unaffected. Even the eyelids, which are known for flaring up when an allergy is due to particulate matter, probably due to iron particles being fairly heavy and falling to the ground quite quickly.
Why Is Contact Dermatitis Not Usually Caused By An Iron Allergy?
There is no biomechanical characteristic that would make iron appear to be different to metals like chromate or nickel, the usual metals people are allergic to. However, if you’re reacting to something you have touched, it is likely going to be something other than iron.
Not only is iron highly prevalent in consumer products and generally safe for day to day use, it is also usually combined, or coated with, other metals such as chrome, manganese, copper or molybdenum. So it is likely you may be allergic to these other metal compounds instead of iron.
If you work with iron, like the above two cases, practicing proper hygiene can go a long way. Wash your work clothes daily to avoid long exposure to iron particles on your skin.
Is Iron Metal Hypoallergenic?
There is speculation among researchers that iron and iron-containing compounds are safe for most of us due to our exposure to them in early fetal life. Iron is also a basic constituent of the body and it is widely known that iron deficiencies predispose us to many other types of ailments. So it is speculated that due to the early contact with iron and iron-containing substances, most people’s bodies do not see it as a threat when touched and their skin will not react to it(10).
In other words, for most people, iron metal is considered to be hypoallergenic (posing a reduced risk) or even non-allergenic (posing no risk).
Even people who are allergic to iron supplements will often find that touching iron metal causes no issues.
The speculation for the rare instances of iron-related contact dermatitis is that the cause of the allergy is either due to a lack of iron sensitization during fetal life or it could be a loss of tolerance in adult life. In the case of the two men mentioned above, their constant exposure to iron particles due to their work is also seen as a factor.
Cast Iron Cookware and Allergies
Last but not least, iron allergies may be exacerbated through the use of cast iron cookware. Almost purely made of iron (~97.99%), cast iron pots and pans offer flavor like no other cookware material does. There’s definitely a distinctive flavor a slow meal boasts!
However, cooking with cast iron pots leads to iron being pulled into your meals. Especially more acidic types of meals will leach more iron from the cookware. This could result in you ingesting more iron without even knowing it!
Excess iron can cause toxicity and can be like having rust in your blood vessels, aka not good.
While menstruating women and young children can do with iron supplementation, men and older women may be at risk of overdoing it. So it’s worth getting your iron levels checked before investing in cast iron cookware!
Iron Allergy Treatments
If you have an iron allergy rash from touching iron, antihistamines may do the trick to reduce the inflammation and any symptoms of contact dermatitis. You should also consult your doctor for a proper prescription if you have a severe rash.
If you are diagnosed with an allergy to iron supplements, the most effective treatment is to avoid the use of oral and IV iron and, instead, increase your natural intake through foods.
However, if you suffer from iron deficiency anemia either due to malabsorption or other causes, you will need to take supplemental iron in order to help your body get back on track. Desensitization protocols are proving to be an effective method to assist people with iron deficiencies and iron allergies get back to health.
If your doctor prescribes such a protocol, it can be given either with oral or intravenous iron depending on the level of your sensitivity. In either case, you will be under complete medical supervision and these doses will be supplied in small amounts (about a tenth of a regular dose) over a long period of time.
It may take up to 9 months for your iron levels to return to normal following a desensitization protocol but you should find it easier to take iron supplements as needed from that point forward.
Final Thoughts
In general, true iron allergies are quite rare. Many people may experience gastrointestinal discomfort after taking oral iron. However, severe iron allergies, like anaphylaxis or severe contact dermatitis, are more rare than many people realise.
If you have iron deficiency anemia, the benefits of iron far outweigh the risks and can greatly help you get back to health!
All in all, it’s best to follow your prescription to the letter. Always consult your doctor if you notice any symptoms of allergies or discomfort or if you have any questions about the best protocol for you.
References
- Iron and Pollen Allergy in Women – Franziska Roth-Walter, Medical University of Vienna, July 2020
- Linking iron-deficiency with allergy: role of molecular allergens and the microbiome – Royal Society of Chemistry – Franziska Roth-Walter, Luis F. Pacios, Rodolfo Bianchini and Erika Jensen-Jarolim, November 2017
- New recommendations to manage risk of allergic reactions with intravenous iron-containing medicines – European Medicines Agency press release, June 2013
- Safety of Oral and Intravenous Iron – DeLoughery T.G – Acta Haematologica, May 2019
- Two case reports of desensitization in patients with hypersensitivity to iron – Edgardo Chapman, Drixie Leal, Leidy Alvarez, Mónica Duarte & Elizabeth GarcÃa – World Allergy Organization Journal, October 2017
- Oral iron cutaneous adverse reaction and successful desensitization – N Ortega, R Castillo, C Blanco, M Alvarez and T Carrillo – PubMed, January 2000
- Development of hypersensitivity reactions after using different oral iron preparations – Öner Özdemir and Mustafa Büyükavcı – Istanbul Med, 2018
- Hypersensitivity reactions to intravenous iron: guidance for risk minimization and management – David Rampton, Joergen Folkersen, Steven Fishbane, Michael Hedenus, Stefanie Howaldt, Francesco Locatelli, Shalini Patni, Janos Szebeni, and Guenter Weiss – The National Center for Biotechnology Information, November 2014
- Iron oxide nanoparticles may damage to the neural tissue through iron accumulation, oxidative stress, and protein aggregation – Zahra Yarjanli, Kamran Ghaedi, Abolghasem Esmaeili, Soheila Rahgozar and Ali Zarrabi – BMC Neuroscience, June 2017
- Allergic contact sensitization to iron – Rudolf L Baer, M.D – The Journal of Allergy and Clinical Immunology, January 1973
