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07/19/2024 | Press release | Distributed by Public on 07/19/2024 11:02

Drug Rashes: 7 Medications That Can Cause Skin Reactions

Key takeaways:

  • Antibiotics, anti-seizure medications, and nonsteroidal anti-inflammatory drugs (NSAIDs) can cause a variety of skin reactions. Warfarin, furosemide, and allopurinol can too.

  • Skin reactions from medications range from mild rashes to severe, life-threatening conditions such as Stevens-Johnson syndrome and toxic epidermal necrolysis.

  • Reach out to your healthcare team any time you develop a rash while taking medication. They can help you prevent the rash from potentially turning into something more serious.

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Between multistep skin care routines, body scrubs, and face masks, we spend a lot of time caring for our skin. And rightly so: Our skin is our first line of defense against germs, and it allows us to sense the world around us.

So, developing a skin reaction to something we consume or touch can be particularly frustrating. Bumps, splotches, and itching are uncomfortable and often seen as unattractive.

Skin reactions have many causes, one of which is medications. But the types of skin reactions caused by medications are quite varied. They can range from a little redness to full-blown skin blistering.

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Below, we'll discuss seven of the most common medications that can cause skin reactions and the types of rashes they cause.

What is a drug rash?

A drug rash is any skin breakout caused by a medication, including over-the-counter (OTC) drugs and supplements. It's usually caused by some type of allergic reaction, but it doesn't have to be. A drug rash can develop immediately after starting a new medication, or it can take days or weeks.

Drug rashes cause changes in the color or texture of your skin, including things like:

  • Discoloration (like red or brown blotches)

  • Bumps

  • Peeling

  • Blistering

Drug rashes are often itchy, but they can also be painful or have no sensation-related symptoms at all.

Common types of drug rashes

Medication-related rashes are grouped in many ways. But it's easiest to classify them as either common and mild, or rare and life-threatening.

Most (almost 90%) of all skin drug reactions are what are called exanthematous maculopapular rashes. These terms mean the rash:

  • Is widespread all over the body (exanthematous)

  • Consists of flat (macules) and raised (papules) patches of skin that are typically red or violet-brown, depending on your skin tone.

Hives and other allergic reactions are the next most common.

This isn't a comprehensive list. But here are some of the more well-known drug rashes, starting with the most common.

Type of drug rash

Description

Common cause

Exanthematous (maculopapular) reaction

This typically starts as small bumps on the chest, stomach, or back, and spreads to the arms and legs.

In white skin, the bumps are red or pink.

In darker skin tones, they can look purple, brown, or even skin-colored.

Antibiotics (like cephalosporins)

Anti-seizure medications (like carbamazepine)

Hives, angioedema, and anaphylaxis

Hives are itchy, raised patches on the skin.

Angioedema is related to hives, but the swelling happens under the skin.

Both of these conditions can turn into a more life-threatening reaction called anaphylaxis.

Antibiotics (like penicillin)

NSAIDs (like ibuprofen)

Fixed drug eruption

This appears as a single round, red, violet, or brown skin patch.

Occasionally, there are several patches, and sometimes they can blister.

It's called "fixed" because if you restart the same medication, the reaction will reappear on the same spot on your body.

NSAIDs

Antibiotics (like ciprofloxacin)

Drug-induced vasculitis

This is caused by blood vessel inflammation. The inflammation allows blood to leak into the skin.

The resulting rash looks like tiny purple or brown spots that can turn into bumps or blisters.

Antibiotics (like penicillin)

Allopurinol

Drug rash pictures

Here are some skin rash pictures of common drug rashes.

Skin rash photo of a maculopapular rash on the chest.
Close-up of a leg with hives from a drug rash.
Close-up of a typical fixed drug eruption.
Close-up of a leg with a vasculitis rash.

Less common types of drug rashes

Other medication-related rashes are more rare, but they can be life-threatening. They represent about 2% of medication-related skin rashes.

Type of drug rash

Description

Common causes

Erythroderma

This intense rash causes skin redness on more than 90% of the body.

It can progress to more serious problems, like peeling, swelling, and loss of body temperature regulation.

Antibiotics (like sulfonamides)

Anti-seizure medications (like carbamazepine)

Allopurinol

Drug rash with eosinophilia and systemic symptoms (DRESS)

This reaction typically starts as itchy patches or bumps that can appear red (in white skin) or brown/purple (in darker skin tones).

It can also come with bodywide symptoms, such as swelling and fever, and can cause damage to organs like the liver.

Allopurinol

Anti-seizure medications (like carbamazepine)

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)

These two related conditions commonly start with flat, dark-red, purple, or brown patches that can be painful. These can rapidly progress to skin peeling and painful sores in the mouth, eyes, or genitals.

Other symptoms include flu-like symptoms, such as fever and body aches.

They're different only in how much of the skin they affect: SJS affects less than 10% of your body, whereas TEN affects 30% or more.

Antibiotics (like sulfonamides)

Anti-seizure medications (like carbamazepine)

Allopurinol

Acute generalized exanthematous pustulosis (AGEP)

This rapidly spreading rash looks like small, pimple-like white heads.

It becomes life-threatening when organs like the liver, kidney, or lymph nodes get involved.

Antibiotics (like sulfonamides)

Terbinafine

Serum sickness-like reaction (SSLR)

This rash can have many different appearances, including red or violet bumps, hives, or tiny purple or brown spots.

The other symptoms that make it a SSLR include joint aches, fever, and itching.

While this condition is rare, it's typically not life-threatening.

Antibiotics (like penicillins)

Bupropion

Now, let's look at the various types of medications that could cause these skin reactions.

1. Antibiotics like Bactrim

Antibiotics are notorious for a risk of causing skin rashes, allergic reactions, and sensitivity to the sun. Sulfa and penicillin antibiotics are common culprits.

Bactrim

Bactrim (sulfamethoxazole / trimethoprim) is part of a group of medications called sulfonamides. People with "sulfa" allergies are allergic to these types of medications.

It can also cause a range of skin reactions - the most common being an exanthematous rash. It typically happens 1 to 2 weeks after starting Bactrim, and it resolves soon after stopping it. Bactrim has also been linked to skin reactions like SJS/TEN, DRESS, and AGEP.

Keflex

Keflex (cephalexin) is a cephalosporin antibiotic. Compared to other medications in the same class, it has the highest risk of causing a skin reaction.

Like Bactrim, it's been connected to a few possible reactions, including exanthematous rash, hives, and serum sickness.

Penicillin

Penicillin is related to medications like Keflex. They have the same basic chemical structure. This means that if you have a serious reaction to Keflex (or another cephalosporin), you shouldn't take penicillin.

Skin reactions to penicillin range from mild to serious.

2. Hydralazine

Hydralazine (Apresoline) is a blood pressure medication that can cause drug-induced lupus erythematosus (DILE). This is the same as the autoimmune condition systemic lupus erythematosus.

DILE can cause several different rashes, including a red, butterfly-shaped rash across the nose and cheeks and other sun-exposed skin. It can also lead to joint aches, fever, and organ inflammation.

Another well-known cause of DILE is a heart medication called procainamide.

3. NSAIDs like aspirin

Aspirin is a pain and fever reducer. It's a type of nonsteroidal anti-inflammatory drug (NSAID), alongside medications like ibuprofen (Advil, Motrin) and naproxen (Aleve).

Skin reactions to these medications are rare, but possible. They can range anywhere from mild hives to angioedema and anaphylaxis. The following reactions have been reported in people at least 24 hours after taking an NSAID:

  • Exanthematous rashes

  • Fixed drug eruptions

  • Severe reactions like DRESS and AGEP

If you have a reaction to aspirin, it's likely that you'll have a reaction to other NSAIDs too.

4. Furosemide

Furosemide (Lasix) is a diuretic, commonly known as a "water pill." Like Bactrim, it's part of the sulfonamide family. So, if you have an allergy to sulfa antibiotics, it's possible you could react to furosemide too.

Reported skin reactions to furosemide include rash, itching, and hives. More rare and severe reactions have included DRESS, SJS/TEN, and erythroderma.

5. Anti-seizure medications like carbamazepine

Anti-seizure medications cause rash and hypersensitivity reactions in roughly 1 in 10 people who take them. The most common medications to cause rash include:

Mild exanthematous rashes are the most common. The risk of these rashes can be minimized by avoiding high starting doses and increasing your dose slowly over time.

Anti-seizure medications are also associated with DRESS and SJS/TEN. Carbamazepine has a boxed warning for SJS/TEN in people with a specific genetic mutation (HLA-B*1502). There's a strong connection between having this mutation and developing SJS/TEN. This mutation is more common in people of Asian ancestry, so screening in this group before starting carbamazepine is recommended.

6. Warfarin

Warfarin (Coumadin, Jantoven) is a blood thinner that treats and prevents blood clots. Unusual or enlarged bruises can occur if your dose is too high. If this happens, you should call your healthcare team. They'll likely want to do a quick blood draw to test your international normalized ratio (INR), which tells them how much your blood is clotting.

Another rare but serious side effect is warfarin-induced skin necrosis. These are red, violet, or brown plaques that can develop into blisters, ulcers, and skin death (necrosis). The risk is higher in those with certain genetic conditions who have a higher risk for blood clots.

7. Allopurinol

Allopurinol (Zyloprim) is a medication used for decreasing high uric acid levels, most commonly in cancer and gout. The most common side effect that it causes is an itchy, flat, or bumpy rash. This can sometimes progress to severe conditions like DRESS or SJS/TEN.

The risk for developing a more serious skin condition is higher when you're first starting allopurinol. It's also higher in people with impaired kidney health and who're starting at a high dose, and in those with a genetic mutation called HLA-B*58:01.

As a precaution, contact your doctor's office right away if you develop a rash while taking allopurinol.

What should you do if you're having a skin reaction to a medication?

It's easy to ignore a rash and hope it goes away on its own. But rashes can progress to more serious conditions if left untreated.

If you develop a rash after starting a new medication, contact your healthcare team to discuss your symptoms and see if you should continue taking the medication.

If you have a rash, plus any of the following symptoms, it could mean a more serious rash. You should seek immediate medical attention if you have a rash in addition to:

  • Blistering or peeling (on skin or lining of mouth, nose, or genitals)

  • Fever

  • Open sores

  • Pain

  • Shortness of breath

  • Swelling of the face or throat

  • A fast-spreading rash

Frequently asked questions

How do doctors diagnose drug rashes?
expand_more

To diagnose a drug rash, a medical professional will start by looking at your skin and reviewing your medications (including supplements).

In some situations, the diagnosis is pretty straightforward. For example, if you developed a classic rash a week after starting one new medication. But if you take many medications, it can be harder to identify a cause. In this case, a little more detective work may be required.

You may need to stop taking certain medications for a short time, or substitute a certain medication for another to see if your rash clears. Sometimes, a skin biopsy can help diagnose a drug rash.

Keep in mind: Don't stop or change medications without discussing it with your prescriber first. It can be unsafe to stop or change some medications suddenly.

Can you use Benadryl to treat an allergic drug rash?
expand_more

Benadryl (diphenhydramine) is a type of antihistamine. It can help relieve symptoms from some types of drug rashes, like hives or an exanthematous rash. Benadryl works by blocking histamine, a chemical in the body that leads to itching and skin swelling.

But benadryl can also cause drowsiness, so it's best taken at night. If you have a drug rash, your prescriber or other healthcare professional may recommend that you take Benadryl. Or they may prescribe a stronger antihistamine.

The bottom line

Most drug rashes are mild and cause an itchy rash that's red or pink (in fair skin) or purple or skin-colored (in darker skin tones). More severe rashes are much less common. They lead to widespread blisters and are life-threatening.

The most common medications that cause skin reactions are antibiotics, anti-seizure medications, and NSAIDs. There are also well-known individual medications that cause more unique rashes, such as hydralazine, warfarin, and allopurinol.

If you think you have a drug rash, notify your healthcare professional. They can help identify the offending agent and recommend an alternative treatment.

Images used with permission from VisualDx (www.visualdx.com).

References

Al Aboud, D. M., et al. (2022). Cutaneous adverse drug reaction. StatPearls.

American Academy of Allergy, Asthma & Immunology. (2024). Hives (urticaria) and angioedema overview.

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American Academy of Dermatology Association. (n.d.). Rash 101 in adults: When to seek medical treatment.

American Academy of Dermatology Association. (2023). Is it possible to be allergic to aspirin?

Benedetti, J. (2022). Drug rashes. Merck Manual Consumer Version.

Dean, L., et al. (2020). Allopurinol therapy and HLA-B*58:01 genotype. Medical Genetics Summaries.

Fang, H., et al. (2019). A screening test for HLA-B*15:02 ina large United States patient cohort identifies broader risk of carbamazepine-induced adverse events. Frontiers in Pharmacology.

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HF Acquisition Co LLC. (2022). Procainamide HCl injection, solution [package insert]. DailyMed.

Jhaj, R., et al. (2018). Fixed-drug eruptions: What can we learn from a case series?Indian Journal of Dermatology.

Kakagia, D. D., et al. (2014). Warfarin-induced skin necrosis. Annals of Dermatology.

Khan, D. A., et al. (2019). Cephalosporin allergy: Current understanding and future challenges. Journal of Allergy and Clinical Immunology.

Kowalski, M. L., et al. (2015). Seven steps to the diagnosis of NSAIDs hypersensitivity: How to apply a new classification in real practice?Allergy, Asthma & Immunology Research.

Ludmann, P. (2024). Hives: FAQs. American Academy of Dermatology Association.

Mani, R., et al. (2019). Rashes and other hypersensitivity reactions associated with antiepileptic drugs: A review of current literature. Seizure: European Journal of Epilepsy.

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PD-Rx Pharmaceuticals, Inc. (2023). Furosemide tablet [package insert]. DailyMed.

PD-Rx Pharmaceuticals, Inc. (2023). Penicillin v potassium [package insert]. DailyMed.

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GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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