If you've ever experienced a rash, painful, or itchy skin after using a skin-care product, you may have an allergy to one of its ingredients.

While the irritation may be obvious, determining what led to your reaction might be unclear. Everyday products like fragrances, sunscreens, and cosmetics can sometimes lead to contact dermatitis — an itchy rash triggered by exposure to allergens.

Fragrances, preservatives like parabens, and seemingly benign ingredients like essential oils are often the culprits. Part of what makes it challenging to find the source of the irritation is that some ingredients aren't fully disclosed on product labels. For example, fragrance compounds like limonene, also called balsam of Peru, are frequent offenders but may be simply listed as “fragrance” or “perfume” on the product's label. 

Below, we'll explore some common skin-care ingredients that cause allergic reactions and how you can spot them on the labels of your products. However, if you negatively react to a skin-care product, you should consult your healthcare provider for guidance. If you experience swelling and itchiness, you should seek medical care promptly. 

An allergic skin reaction happens when your skin comes in direct contact with something that triggers an immune response. This can lead to redness, itching, swelling, and sometimes blisters or scaly patches, says Austin Ambur, DO, a dermatologist with Sharp Community Medical Group in San Diego.

Several different types of allergic skin reactions can occur. These include:

• Allergic Contact Dermatitis Occurs when an allergen triggers the immune system after direct contact with the skin. Symptoms include redness, itchiness, swelling, and, in severe cases, blisters or scaly patches.

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• Irritant Contact Dermatitis This is caused by damage to the skin barrier from harsh chemicals or irritants, such as soaps and detergents. It isn’t an allergic reaction. Symptoms include burning or stinging, redness, dry and cracked skin, and sometimes swelling.

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• Periorificial Dermatitis This is often seen around the mouth, nose, or eyes. It can look like small, red, itchy bumps or a rash and may be mistaken for acne. However, there won't be blackheads or whiteheads. It is often itchy. While its exact cause isn't fully understood, it may be triggered by topical steroids, certain skin-care products, sunscreen, hormonal changes, and fluoride.

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• Angular Cheilitis This shows up in the corners of the mouth and causes redness, cracking, inflamed skin, and sores. Though it can be confused with a cold sore, it is not contagious. It is often triggered by saliva, drooling, or allergens in oral hygiene or lip products.

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Certain skin-care ingredients can trigger allergic reactions, leading to irritation, redness, and itching. Here is a list of common culprits that you should be aware of when choosing skin-care products:

Fragrance

Description They can be synthetic or natural compounds used to give products a pleasant smell. You can find fragrances in many cosmetics and skin-care products. “Fragrance is [a] huge cause [of] allergies,” says Dr. Ambur. “The thing that [is] very difficult with fragrances is that there's nothing that these companies have to do to show all of their ingredients. So that's typically how they're able to hide a little bit is because they say, ‘Oh, this is a protected ingredient so that nobody can get our same fragrance.’”

How to I.D. Look for the terms “fragrance,” “parfum,” “perfume,” or even “essential oils” on the label. Some products may also contain specific fragrance chemicals like limonene or linalool. “Fragrance doesn’t just mean perfume — it’s used in almost every beauty product under the sun,” says Siobhan O’Connor, coauthor of No More Dirty Looks: The Truth About Your Beauty Products and the Ultimate Guide to Clean and Safe Cosmetics. Fragrance ingredients can even crop up in products labeled “unscented” because companies use special fragrance chemicals known as masking agents to create that nonscent.

Parabens

How to I.D. Look for ingredients ending in “-paraben,” such as methylparaben, propylparaben, or butylparaben.

Formaldehyde Releasing Agents

Description These preservatives release small amounts of formaldehyde over time to prevent microbial growth. For some people, formaldehyde can cause allergic contact dermatitis.

Nickel

How to I.D. Nickel may not always be clearly labeled, but it can be in metallic, shimmery products, or look for items labeled “nickel-tested” or “hypoallergenic.”

PPD (p-Phenylenediamine)

Description PPD is a chemical found in hair dyes and sometimes in dark-toned cosmetics.

Oxybenzone

Description Oxybenzone is a chemical sunscreen ingredient that can cause allergic reactions.

How to I.D. Look for “oxybenzone” or other “-benzone” compounds on the ingredient list, especially in chemical sunscreens.

Lanolin

How to I.D. Look for “lanolin” or products labeled as containing “wool wax” or “wool grease” on the label.

Methylisothiazolinone (MIT)

How to I.D. Look for “methylisothiazolinone” or "MIT" on product labels, especially wet wipes and liquid products.

Propolis

How to I.D. Look for “propolis” or “beeswax” in lip balms and other skin-care products.

FD&C Red 40

Description FD&C dyes are synthetic colorants used in cosmetics, especially in lipsticks and blushes. Red 40, in particular, is known to cause allergic reactions.

How to I.D. Look for “FD&C Red 40” or other FD&C dyes on the label, especially in brightly colored makeup products.

Aluminum

Description Armpits that get red or start to peel after using antiperspirant could be a sign of an allergy to aluminum compounds, says Joshua Zeichner, MD, director of cosmetic and clinical research in the dermatology department at Mount Sinai Medical Center in New York City. Unfortunately, the more powerful your wetness protection is, the more likely you react.

How to I.D. Look for aluminum in the ingredients list.

If you believe you’ve had an allergic reaction, there are several steps to take. Those include:

• Discontinue use. Stop using any skin-care or cosmetic products that you think might be causing the reaction, including makeup, lip balms, and hair dye.
• Streamline your routine. Opt for gentle skin-care products that are fragrance-free and hypoallergenic, even if they say they are for sensitive skin.
• Avoid irritants. Limit your use of harsh cleansers and use lukewarm water or cool water for washing. Do not use hot water, which can worsen the irritation.
• Keep it cool. Use a cold compress to soothe the skin and reduce inflammation if the itching or swelling is severe.
• Don’t scratch. Even though it feels so good, resist the urge to scratch, Ambur says. It will just make things worse.
• Use antihistamines. Over-the-counter allergy meds like Benadryl or Claritin, Allegra, and Zyrtec contain antihistamines that help reduce itching and swelling. Follow manufacturer labels for best results.
• Use moisturizers with ceramides. Apply fragrance-free moisturizers that contain ceramides after cleansing to help restore and protect the skin barrier.
• Use topical steroids. Over-the-counter hydrocortisone creams can help with itching and reduce inflammation. Your healthcare provider can also prescribe stronger topical steroids if necessary.
• Seek medical intervention. If the reaction lasts over a week or you experience severe symptoms like difficulty breathing, facial swelling, or throat swelling, seek immediate medical attention.
• Consult a dermatologist. If the reaction won’t go away, or you don’t know what’s causing it, consult a dermatologist for diagnosis, treatment, and potentially patch testing to identify specific allergens.

There are times when you should consult with a healthcare provider. “If you've tried simplifying your skin-care routine and using gentle, fragrance-free products for more than a week without improvement, you should see a doctor,” says Ambur.

Also, you should seek immediate medical attention if you experience severe symptoms, such as difficulty breathing, facial swelling, throat swelling, or high fevers. These could be signs of a more serious allergic or life-threatening reaction like anaphylaxis.

It's usually best to see a dermatologist for skin reactions, but an allergist can also help with testing and treatment.

• If you're experiencing an allergic skin reaction, stop using anything you think might be causing it.
• Over-the-counter remedies like antihistamines and cold compresses can provide relief.
• Consult a dermatologist if your symptoms continue for over a week or worsen.
• Severe symptoms like difficulty breathing and facial or throat swelling could be signs of a serious allergic reaction and should be seen by a healthcare professional immediately.
• Your healthcare provider can help you identify the source of your reactions through patch tests and other methods.