A drug rash, sometimes called a drug eruption, is a reaction your skin can have to certain drugs.

Almost any drug can cause a rash. But antibiotics (especially penicillins and sulfa drugs), NSAIDs, and anti-seizure drugs are the most common drugs to cause a rash.

Read on to learn more about the different kinds of drug rashes and how to manage them.

Most drug rashes are symmetric. This means they appear the same on both parts of your body.

Drug rashes also don’t tend to cause any other symptoms besides their appearance, though some are accompanied by itching or tenderness.

You can usually separate a drug rash from other rashes since they tend to coincide with starting a new drug. But in some cases, it can take a drug up to two weeks to cause a rash.

The rash usually disappears once you stop taking the drug.

Here’s a look at some of the more common drug rashes.

Exanthematous rashes

This is the most common type of drug rash, making up about 90 percent of cases. It’s marked by small lesions on reddened skin. These lesions can be either raised or flat. Sometimes, you might also notice blisters and pus-filled lesions.

Common causes of exanthematous drug rashes include:

  • penicillins
  • sulfa drugs
  • cephalosporins
  • anti-seizure drugs
  • allopurinol

Urticarial rashes

Urticaria is another word for hives. Hives are the second most common type of drug rash. They’re small, pale red bumps that can form larger patches. Hives are usually also very itchy.

Common causes of urticarial drug rashes include:

  • non-steroidal anti-inflammatory drugs (NSAIDs)
  • ACE inhibitors
  • antibiotics, especially penicillin
  • general anesthetics

Photosensitivity reactions

Some drugs can make your skin extra sensitive to ultraviolet light. This can result in an itchy sunburn if you go outside without proper protection.

Drugs that tend to cause photosensitivity include:

  • certain antibiotics, including tetracycline
  • sulfa drugs
  • antifungals
  • antihistamines
  • retinoids, such as isotretinoin
  • statins
  • diuretics
  • some NSAIDs

Erythroderma

This type causes nearly all of the skin to become itchy and red. The skin may also grow scaly and feel hot to the touch. Fever might also occur.

Many drugs can cause erythroderma, including:

  • sulfa drugs
  • penicillins
  • anti-seizure drugs
  • chloroquine
  • allopurinol
  • isoniazid

An underlying health condition can also cause erythroderma.

Warning

Erythroderma can become serious and life-threatening. Seek immediate medical attention if you think this is the type of rash you have.

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

SJS and TEN are considered the same condition, but there’s a slight difference between the two:

  • SJS involves less than 10 percent of the body.
  • TEN involves more than 30 percent of the body.

SJS and TEN are marked by large, painful blisters. They can also cause large areas of the top layer of your skin to come off, leaving raw, open sores.

Common drug-related causes include:

  • sulfa drugs
  • anti-seizure drugs
  • some NSAIDs
  • allopurinol
  • nevirapine
Warning

SJS and TEN are serious reactions that can be life-threatening. They both require immediate medical attention.

Anticoagulant-induced skin necrosis

Some blood thinners, such as warfarin, can cause anticoagulant-induced skin necrosis. This causes the skin to become red and painful.

Eventually, the tissues beneath the skin die. It usually only happens at the start of taking a very high dose of a blood thinner.

Warning

Anticoagulant-induced skin necrosis is a serious reaction that requires immediate medical attention.

Drug reaction with eosinophilia and systemic symptoms (DRESS)

DRESS is a rare type of drug rash that can be life-threatening. It can take two to six weeks for symptoms to appear after starting a new drug.

A DRESS rash looks red and often begins on the face and upper body. Accompanying symptoms are severe and can involve the internal organs. They include:

  • fever
  • swollen lymph nodes
  • facial swelling
  • burning pain and itchy skin
  • flu-like symptoms
  • organ damage

Drugs that can cause DRESS include:

  • anticonvulsants
  • allopurinol
  • abacavir
  • minocycline
  • sulfasalazine
  • proton pump inhibitors
Warning

DRESS is a very serious reaction that requires immediate medical attention.

Drug rashes and reactions happen for several reasons, including:

  • an allergic reaction
  • a buildup of the drug that causes toxicity to the skin
  • a drug makes the skin more sensitive to sunlight
  • interaction of two or more drugs

Sometimes drug rashes can be spontaneous and develop without a cause.

Certain factors can also increase your risk for developing a drug rash, such as being older and female.

Other risk factors include having:

  • a viral infection and taking an antibiotic
  • a weakened immune system due to an underlying condition or other drug
  • cancer

In many cases, drug rashes go away on their own once you stop taking the drug that caused your rash.

If the rash is very itchy, an antihistamine or oral steroid can help manage the itching until the rash clears up.

Always talk to your doctor first before discontinuing a drug. This is especially important it you take multiple drugs. In this case, your doctor will have you follow a specific plan of discontinuing each drug until you figure out what’s causing the reaction.

If you have severe urticaria, erythroderma, SJS/TEN, anticoagulant-induced skin necrosis, or DRESS, you’ll need more intensive treatment. This might include intravenous steroids and hydration.

In many cases, a drug rash isn’t anything to worry about. They usually clear up once you stop taking the drug. Just make sure to talk to your doctor before discontinuing any prescribed drug.

For symptoms of a more severe drug rash, head to urgent care or a hospital as soon as possible to avoid complications.