What Is DRESS Syndrome and What Causes It?

Hives, rashes, and trouble breathing are all potential signs of an allergic reaction. One potential trigger for allergic reactions is starting a new medication. In very rare cases, medication allergies can be dangerous or life-threatening.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome is one example of a serious medication allergy. It’s a type of severe allergic reaction to a medication that occurs anywhere from 2 to 8 weeks after starting a medication. DRESS syndrome is characterized by fever, rash, abnormal blood tests, and swollen lymph nodes (small glands that filter foreign substances and contain cells that help the body fight infection). The condition also affects at least one internal organ — most often the liver.

DRESS syndrome is rare — estimated to affect between 1 in 1,000 to 1 in 10,000 people exposed to a medication. However, it’s a life-threatening condition with about a 10% mortality rate — meaning 10% of those who develop it die.

Below, we’ll discuss medications that are closely linked with DRESS syndrome, potential signs of this condition, and people who may have a greater chance of developing this severe allergic reaction.

What causes DRESS syndrome? 

The precise cause of DRESS syndrome isn’t well understood, but it’s thought that some cases may be caused by a defect in the way the liver metabolizes (breaks down) certain medications. Reactivation of a virus — when a virus that is inactive (dormant) in your body becomes active again — may also play a role by triggering the immune system to overreact.

The viruses typically associated with DRESS syndrome are human herpesvirus 6 (HHV-6, a virus that causes roseola), human herpesvirus 7 (HHV-7, another cause of roseola), and human herpesvirus 4 (HHV-4 or Epstein-Barr virus, the virus that causes mononucleosis).

Many people may have had one or more of these infections during childhood or early adulthood. They often remain dormant for a lifetime, causing no problems. It’s unclear why these viruses become active again for some people.

What medications can cause DRESS syndrome?

There’s a delay between the moment a person starts a medication and when DRESS syndrome symptoms begin. This is quite different from many common medication reactions, which often occur within hours or days of taking a medication. With DRESS syndrome, the reaction can occur anywhere between 2 to 8 weeks after starting a medication and continue even after stopping it.

The medications most frequently associated with DRESS syndrome are:

• Anti-seizure medications, especially lamotrigine (Lamictal), carbamazepine (Tegretol), and phenobarbital 

• Allopurinol (Zyloprim), a gout medication

• Antibiotics, especially minocycline (Minocin), vancomycin (Vancocin), and those that are sulfa-based 

• Sulfasalazine (Azulfidine), a medication used to treat autoimmune diseases like rheumatoid arthritis and ulcerative colitis

• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin) and celecoxib (Celebrex)

• HIV medications, most commonly nevirapine (Viramune)

• Certain cancer medications, such as vemurafenib (Zelboraf)

This isn’t an all-inclusive list of medications that can cause DRESS syndrome. Please speak with your healthcare provider or pharmacist to ask if any of your medications are known to cause this condition.

Is DRESS syndrome a medical emergency?

Yes. People with this condition may require a hospital stay to manage and treat the condition. An intensive care unit (ICU) setting may also be necessary because DRESS syndrome can seriously affect internal organs. 

Because DRESS syndrome is fatal for about 10% of those who develop it, early diagnosis and treatment are essential. A delay in treatment could have grave consequences.

What are the symptoms of DRESS syndrome?

There isn’t one test that can confirm if a person has DRESS syndrome. Rather, healthcare providers use criteria to help them diagnose the condition.

These criteria state that at least three of the following should be present to consider a DRESS syndrome diagnosis:

• A person is in the hospital

• A fever greater than 100.4℉ (38℃)

• A sudden rash develops — usually redness involving the entire body, followed by peeling

• Enlarged lymph nodes in at least two different areas of the body

• Problems with at least one internal organ, such as the liver, thyroid, kidney, lung, or heart

• Abnormal blood levels of lymphocytes (a type of white blood cell), eosinophils (another type of white blood cell), or platelets (a blood component necessary for forming blood clots)

• Suspicion that these symptoms may be related to a medication

Most of these criteria would be discovered by a healthcare provider, but there are two you can watch for at home. If you ever develop a sudden, severe rash along with a fever, seek medical attention right away.

How do you treat DRESS syndrome?

First, it’s crucial to stop the triggering medication. This can pose a challenge if the person takes multiple medications. Be sure to give your healthcare provider a complete list of all medications — including over-the-counter and herbal products.

Because internal organs — such as the liver, kidney, heart, and lung — are often affected, almost all people affected will need supportive care in an ICU or a burn unit setting. Supportive care can include dialysis for kidney problems and medications to help relieve heart, lung, and thyroid symptoms.

Oral or intravenous (IV) corticosteroids — such as prednisone or methylprednisolone — are often given to calm down the immune system’s reaction and prevent organ damage. Typically, oral steroid doses are slowly decreased over a period of 6 to 8 weeks after the initial treatment is complete. Corticosteroid creams can help control rash symptoms.

Antiviral medications may be useful in some cases — such as when DRESS syndrome is thought to be linked to virus reactivation. Ganciclovir (Cytovene) is the antiviral medication that’s been most studied for treating DRESS syndrome.

What is the outlook for someone with DRESS syndrome?

As previously mentioned, approximately 10% of people with DRESS syndrome don’t survive. But, with prompt diagnosis and removal of the triggering medication, most people will recover completely.

Even so, long-term problems due to DRESS syndrome are still possible. A small study showed complications occurred in roughly 11% of people who developed the condition. Younger people in the study were more likely to develop autoimmune diseases, such as type 1 diabetes or Graves’ disease (an autoimmune thyroid condition). Older study participants were more vulnerable to permanent organ damage such as kidney failure. 

Other long-term complications include lupus, alopecia areata (a condition that causes hair loss), and vitiligo (a condition where patches of skin lose their color). The reasoning for these long-term problems isn’t fully understood.

What factors raise your risk of getting DRESS syndrome?

While risk factors still aren’t completely understood, certain genetic traits or changes may raise the risk of a person developing DRESS syndrome. Some genes play a role in how certain medications are metabolized in the body. If the body isn’t breaking down medications properly, there is concern DRESS syndrome could occur.

Rapidly raising the dose when first starting certain medications may also be linked to DRESS syndrome. The anti-seizure medications lamotrigine and carbamazepine have boxed warnings (the FDA’s strictest medication warning), which state that this condition has been reported in people who started with higher doses than what’s recommended.

Two of the viruses associated with DRESS syndrome — HHV-6 and -7 — are common infections that usually become inactive after the initial infection resolves. However, people with DRESS syndrome who test positive for reactivation of these viruses tend to have longer hospital stays and worse outcomes.

What can you do to lower your chances of getting DRESS syndrome?

If anyone in your family has experienced DRESS syndrome, speak with your healthcare provider. As discussed above, there are some genetic markers that may raise your chance of developing a reaction to certain medications. Your healthcare provider may be able to screen you for these genetic markers and advise you if you should be cautious with certain medications.

If you’re prescribed a medication where the dose is raised slowly in the beginning, this is most likely done to lower your risk of complications, quite possibly for DRESS syndrome. Be sure to follow your healthcare provider’s instructions carefully, and always double check with them if you are unsure of your dose.

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Written by:

Valerie Hanft, MD

Valerie Hanft, MD, has practiced general medical and pediatric dermatology for 20 years. She has served on the FDA Task Force, participated in many clinical trials, and authored multiple peer-reviewed publications.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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