Many of us are familiar with the idea of seasonal allergies to pollen or know of someone who’s allergic to pets, while food allergies have become increasingly more common over the years. However, another common source of allergies that often gets overlooked? Cosmetic products.
Applied directly to the skin and formulated with a variety of botanical ingredients and potential chemical irritants, cosmetics and other topical products represent a source of allergies for many—even worse, with the complexity of many modern formulations and the addition of new ingredients can make identifying the root cause of a potential allergy difficult to pin down. Let’s review the basics of allergies in cosmetic products, starting with the basic definitions, common sources of allergies, the history of allergic and toxic cosmetics, and a few tips to diagnose, manage, and avoid allergic reactions to everyday products.
What is an allergy?
Before we get into the weeds, let’s cover some common terminology first:
Antigens, allergens, and antibodies
An antigen can be any foreign substance that’s recognized by the immune system, usually a protein, peptide, polysaccharide, lipid, or nucleic acid. An allergen, on the other hand, is a specific antigen that prompts an allergic reaction.
Antigens are targets for antibodies and fall into four main superclasses: exogenous, endogenous, autoantigen, and neoantigen. In the case of cosmetic allergies, this means primarily focusing on exogenous antigens.
- Exogenous: A foreign substance from outside of the body, including a plant, animal, product, or chemical.
Getting more specific, an allergen is any antigen that’s capable of causing an allergic reaction by the body’s immune system. Common examples are:
- Seasonal pollen from plants like grass, trees, or ragweed.
- Foods like peanuts, shellfish, or eggs.
- Mold spores.
- Pet dander.
- Stings from insects like bees.
- Chemicals found in consumer products, like preservatives.
Antibodies—also known as immunoglobulins—are products of the immune system that bind to a foreign substance like an antigen. Antibodies are often specific for each antigen, or for antigens with common features. Antibodies fall into five different classes: IgG, IgM, IgA, IgD, and IgE. Each of these different classes of antibodies can be expressed in a different part of the body and perform a unique function—again, for simplicity and in the context of cosmetic allergies, we’ll highlight IgE, given its prevalence in allergic reactions.
- IgE: Present in low concentrations in the bloodstream, IgE is primarily responsible for the release of chemicals involved in allergic reactions. Binds to mast cells in tissues and basophils in the bloodstream allowing them to release compounds like cytokines and histamines, which dilate the blood vessels and allow them to “leak” antigen-fighting compounds into the affected areas of the body.
Image adapted from The Biologist using BioRender
What causes an allergic reaction?
In many cases, the chemical that causes the classic signs of an allergic reaction is histamine. While histamine has a variety of functions in different parts of the body, in the context of allergic reactions, histamine is the chemical released by mast cells in response to an antigen. Histamine is responsible for stimulating blood flow to tissues as part of the inflammatory response.
In most circumstances, this reaction is a good thing: Histamine secretion and the inflammatory response are important to get antibodies and other healing compounds to the site of irritation or infection in order to clear the foreign antigen from the body. However, once we’ve experienced an allergic reaction often enough to cognitively understand the cause, duration, and effects, the body’s overzealous immune response can become detrimental. In such cases, many allergy sufferers take an antihistamine to blunt the effects of the body’s immune response. In severe cases involving anaphylaxis, an injection of epinephrine—like an EpiPen—may be required in order to counteract the immune response.
How do we develop allergies?
Any substance that can produce an allergic reaction is known as an allergen. An allergy is caused by the body’s immune system reacting to an allergen that it’s been exposed to. Upon first exposure to an allergen, the body may not mount a full-throated immune response to the allergen; however, the body has now been sensitized to the substance in question, meaning that future exposures may result in a more severe allergic reaction than before.
Irritation vs. Allergy
When discussing cosmetic products, we’re dealing with topical solutions that are applied to the skin. Most compounds in modern cosmetics that trigger an immune response will lead to localized allergic reactions in the area they’ve been applied, rather than a systemic allergic reaction that involves the entire body. In some cases, a consumer might develop a rash when a particular product or ingredient is applied to the skin—this is a common condition known as contact dermatitis, or swelling and itching of the skin. There are two types of contact dermatitis:
Irritant contact dermatitis
More painful than itchy, irritant contact dermatitis is a rash that develops in response to exposure to a chemical substance like acids, cleaning products, or solvents. Separate from an allergic response because the immune system isn’t responsible for the observed symptoms.
Allergic contact dermatitis
More itchy than painful, allergic contact dermatitis may develop quickly after the initial exposure to the antigen, or take several days to manifest. Common causes include plants like poison ivy, latex, cosmetic fragrances, nickel metal, some preservatives, or antibiotic medications.
Irritants, allergens, and toxins in cosmetics
What are some examples of compounds in consumer products that could contribute to an allergic reaction? According to the FDA, common allergens in cosmetics fall into one of five major classes:
- Natural rubbers, like latex.
- Fragrances, like linalool (found in lavender, citrus, and rosewood), D-limonene (also found in citrus), or cinnamaldehyde (found in cinnamon). Fragrances are the most frequent cause of contact dermatitis from cosmetic products.
- Preservatives, like formaldehyde or parabens.
- Dyes or color additives, like paraphenylenediamine (PPD).
- Metals, like nickel and gold.
Retinol, a form of vitamin A and a compound that gets a lot of attention in skincare, is infamous for the initial reaction it generates when first adding it to a skincare regimen. Known as retinol burn or retinization, the body’s initial reaction to retinol includes inflammation, itchiness, and peeling of the skin where retinol has been applied. If you’ve recently started retinol, it may seem like an allergic reaction at first, but this response is normal and expected. As with any compound, a small number of cases may be genuine allergic reactions, though research has shown that retinoids like retinol behave more like an irritant than an allergen because the immune system isn’t activated in response.
Many of these compounds may seem like modern inventions or additions—surprisingly, however, the incorporation of harmful and toxic chemicals in cosmetics has a storied, tragic history.
History of toxic compounds in cosmetics
Though completely unintentional, human history is littered with stories of toxic compounds being trumpeted as miracle cures or salves for a variety of vanity concerns. Centuries ago, ancient Egyptians applied a multitude of toxic metallic compounds like malachite, galena, and kohl around their eyes. Containing heavy metals like lead, copper, or antimony, these early cosmetics posed a significant danger because of the area in which they were applied: The thin nature of the ocular skin, coupled with its proximity to mucosal membranes in the eyes and nose, made it far easier for the toxic compounds to absorb into the body. The ancient Greeks and Romans expanded upon the use of otherwise-toxic cosmetics, making use of white lead-based creams to even out skin tone and facial blemishes and red lead-based products for a hint of natural rouge.
Why the emphasis on whitening compounds to give the face a paler hue? In many cultures throughout history, pale skin was seen as a symbol of wealth, privilege, and luxury: Those with darker, tan skin often acquired it by being outside performing menial labor in the sun, while those with money could afford to stay indoors in comfort. Even after the Scientific Revolution, wealthy Europeans continued to apply toxic creams to accentuate their features. In 1760, a prominent Irish socialite, Maria Gunning, became one of the first recognized victims of cosmetics, killed at 28 by the lead and mercury that had accumulated in her body over the years. Her daily routine?
“For a whitener, she used ceruse, a combination of lead oxide, hydroxide and carbonate; for rouge, cinnabar, a scarlet form of mercury sulfide; and for lipstick, fucus, or seaweed extract, which also contained mercury.”
Hearing the numerous colors that lead compounds can produce, this use of lead-based ingredients may sound familiar: It was only in 1978 that the United States phased out the use of lead paint, while the EPA prohibited the use of tetraethyl lead in gasoline in 1986 before fully banning it in passenger cars in 1996. Besides exacerbating any skin blemishes that the white lead laden cream attempted to conceal, lead serves as a potent neurotoxin once it accumulates in the body by interrupting the normal function of calcium in the brain as a signaling molecule. Symptoms of lead poisoning in adults range from headache, abdominal pain, and high blood pressure to mood disorders, reduced sperm count, or an increased possibility of miscarriage. In children, lead poisoning is even more detrimental because of the disruptive effects the toxic metal has on neurological development. Symptoms of lead poisoning in children—notably seen in the water crisis impacting Flint, Michigan—can include developmental delay, learning disabilities, vomiting, and seizures.
As a more modern example of cosmetic contamination, a 1933 mascara branded as Lash Lure used the toxic chemical paraphenylenediamine—an irritant we mentioned earlier that commonly saw use as a dye—in order to darken and color both eyebrows and eyelashes. Upon contact with the skin, however, Lash Lure caused severe dermatitis, ulcers, and conjunctival edema, eventually leading to bacterial infections, blindness, and death. The horrors of Lash Lure contributed to the eventual passage of the 1938 federal Food, Drug and Cosmetic Act.
How to manage cosmetic allergies
Preventing an allergic response to cosmetic products can be a Sisyphean challenge due to the sheer number of chemicals and compounds in the products we interact with on a daily basis. When factoring in allergens from vaporized or aerosolized compounds, including fragrances or volatile solvents, it’s easy to see how little control we have over the chemicals that we’re exposed to.
Diagnosing a cosmetic allergy
Diagnosing an allergy to cosmetic products—or to any type of allergen—usually involves a skin test. If you haven’t had a severe allergic reaction or particular skin conditions like psoriasis or eczema, a skin test can be a useful way to evaluate how a variety of potential allergens may or may not trigger allergic contact dermatitis.
Skin prick test
An assay, usually conducted on the forearm or upper back, that can test the allergic response to as many as 50 allergens at once by adding a small amount of allergen extract to the surface of the skin, pricking the skin with a small needle to allow the allergen to penetrate, then measuring the size of any red mark that develops on the skin after a short period of time.
Skin injection test
Similar to a skin prick test, except the allergen in question is suspended in a liquid solution. A small volume of the allergen solution is then injected into the skin, creating a small bubble that is evaluated similarly to the skin prick test.
Patch test
Commonly done to evaluate delayed allergic reactions, a patch test involves taping a series of small discs containing different allergens to the surface of the skin. The patches are worn for 48 hours, removed, then evaluated to see which allergen (if any) produced a significant allergic response. If the patient suspects that a personal consumer product might be the source of any allergic contact dermititis that they’re suffering from, the patch test may incorporate a proper dilution of the product as one of the allergens in question.
Preventing a cosmetic allergy
If you’re concerned about a potential allergic reaction to a new cosmetic product, there are a few tips to minimizing the detrimental effects. If you’re already noticing symptoms of allergic contact dermititis and have an idea of which product could be to blame, trial-and-error can help to narrow down the list of potential culprits. Here are a few tips to keep in mind along the way:
- Manufacturers are still required to list the ingredients used in cosmetics on the product label, so consumers can evaluate the compounds for themselves to check if any incorporated ingredients may cause them allergies.
- When trying a new cosmetic product, mimic the procedure of the patch test. Apply a small sample of the product to a portion of the skin, like the inner forearm, and observe any response.
- You may be tempted to look for hypoallergenic products. It’s possible that these products may contain ingredients that are less likely to cause an allergic reaction in a majority of users; however, after the FDA attempted to regulate the use of the term “hypoallergenic” in cosmetics during the mid-1970s, the U.S. Court of Appeals for the District of Columbia struck down the regulation by the FDA.
Wrapping up
Allergies can be a nuisance, and few things can be more annoying than experiencing an allergic reaction to a product meant to improve our appearance, comfort, and confidence. While many products are tested to identify whether or not they elicit any allergic responses, because of how the FDA regulates cosmetic products, it can be difficult to pin down whether or not a particular item will cause an allergy. Making that process more difficult, predisposition to an allergen is highly variable from person to person, meaning that common allergens may not generate a reaction in some individuals, while other compounds may generate a reaction in others in rare circumstances.
The only solution? Constant vigilance on the part of the consumer. Always read the product label. If you’ve experienced any symptoms of an allergic reaction, try to narrow down what the cause may be. Have you incorporated any new products into your routine? Have you eaten any uncommon foods lately? Even transient bouts of stress can heighten the body’s immune response and make it more susceptible to overreact to otherwise inocuous allergens.
If you’re concerned enough to seek a diagnosis, talk to your doctor about a skin test for common allergens. If a particular product in your routine is a suspect, mention it to your doctor and make sure that they’re able to incorporate the product into the panel of allergens being screened for.
