Drug-Induced Eruptions
Skin rashes and reactions caused by medications
Quick Facts
- Type: Skin (dermatologic) drug reaction
- Common triggers: Antibiotics, anti-seizure drugs, many others
- Usual feature: Rash appearing after starting a new medicine
- Seek emergency care: Blistering, skin peeling, facial swelling, fever
Overview
Drug-induced eruptions are rashes and other skin reactions that occur as a side effect of medications. They are one of the most common types of adverse drug reaction and can be caused by prescription drugs, over-the-counter medicines, and herbal products. Most drug eruptions are mild and resolve once the responsible medication is stopped.
However, a small number of drug reactions are severe and can be dangerous, involving blistering, peeling of the skin, swelling, internal organ involvement, or a serious allergic response. Recognizing the difference between a mild rash and the warning signs of a serious reaction is important, because severe drug eruptions are medical emergencies. Almost any medication can cause a reaction, and the rash may appear days or even weeks after starting the drug.
Symptoms
The appearance varies widely depending on the type of reaction.
- A widespread red, spotty, or measles-like rash, often the most common type
- Hives (raised, itchy welts) that may come and go
- Itching, which can be intense
- Red or purple patches, sometimes with blistering or peeling skin
- Swelling of the face, lips, or tongue
- Fever, feeling unwell, and swollen glands in more serious reactions
Warning signs of a serious reaction include painful skin, blisters, peeling, sores in the mouth or eyes, widespread swelling, difficulty breathing, and fever. These need emergency care.
Causes
Drug eruptions occur when the immune system reacts to a medication or when a drug irritates the skin directly. The reaction may be a true allergy or a non-allergic response.
- Immune (allergic) reactions: the immune system identifies a drug as a threat and mounts a response that affects the skin.
- Common culprit medications: antibiotics (especially penicillins and sulfa drugs), anti-seizure medicines, gout medications, certain pain relievers, and water pills, among many others.
- Non-allergic mechanisms: some drugs cause rashes through direct effects on the skin or by increasing sensitivity to sunlight.
Almost any drug can trigger a reaction, and a person can react to a medication they have tolerated before.
Risk Factors
- Taking many different medications
- A previous drug allergy or reaction
- Certain viral infections, which can increase the chance of a rash with some antibiotics
- A weakened immune system or certain genetic factors
- Female sex, which is associated with some drug reactions
- Recently started or newly added medications
Diagnosis
Diagnosis relies mainly on the history and the appearance and timing of the rash.
- Medication history: identifying any new drugs started in the days to weeks before the rash appeared is the most important step.
- Skin examination: the pattern and features of the rash help distinguish mild from serious reactions.
- Blood tests: may check for signs of organ involvement or a severe reaction.
- Skin biopsy: occasionally used to clarify the type of reaction.
- Allergy evaluation: in some cases, testing helps confirm which drug is responsible after recovery.
Treatment
The most important treatment is to stop the medication that caused the reaction, under medical guidance, and to provide relief while the skin recovers.
- Stopping the culprit drug: the responsible medicine is discontinued and a safer alternative is chosen if needed.
- Antihistamines: help relieve itching and hives.
- Topical corticosteroids: creams or ointments to calm inflammation and itching.
- Oral or intravenous corticosteroids: for more widespread or severe reactions.
- Emergency treatment: severe reactions such as blistering skin disease or anaphylaxis require hospital care and intensive support.
- Allergy documentation: recording the drug allergy so it is avoided in the future.
Prevention
- Tell every healthcare provider and pharmacist about past drug reactions
- Keep an up-to-date list of medications and known allergies
- Wear a medical alert bracelet if you have had a serious drug reaction
- Avoid the specific drug that caused a reaction and closely related medicines as advised
- Start new medications one at a time when possible so a reaction can be traced
- Report any new rash after starting a medicine to your doctor
When to See a Doctor
Contact a doctor if you develop a rash after starting a new medication, even if it seems mild, so it can be assessed. Stop the suspected drug only as directed. Call emergency services or go to the emergency department immediately for:
- Blistering, peeling, or painful skin, or sores in the mouth, eyes, or genitals
- Swelling of the face, lips, tongue, or throat, or difficulty breathing
- A widespread rash with high fever and feeling very unwell
- Dizziness, fainting, or a rapid pulse after taking a medication
Frequently Asked Questions
What is a drug-induced eruption?
It is a skin reaction caused by a medication, ranging from a mild, itchy rash to rare but serious reactions with blistering and peeling. Almost any drug can cause one, and the rash may appear days or weeks after the medicine is started.
Which medications most often cause drug rashes?
Common culprits include antibiotics such as penicillins and sulfa drugs, anti-seizure medications, gout medicines, certain pain relievers, and water pills. However, virtually any medication, including over-the-counter and herbal products, can cause a reaction.
How do I know if my drug rash is serious?
Warning signs of a serious reaction include painful or blistering skin, peeling, sores in the mouth or eyes, facial or throat swelling, difficulty breathing, and a high fever with feeling very unwell. These are emergencies and need immediate care.
What should I do if I get a rash after starting a new medicine?
Contact your doctor promptly so the rash can be assessed, and stop the suspected drug only as directed. If you have blistering, peeling, swelling of the face or throat, or trouble breathing, seek emergency care right away.
Can I take the same medication again after a drug reaction?
Usually not. Once a drug has caused a reaction, it is generally avoided in the future, along with closely related medicines. Tell all your healthcare providers about the reaction and keep a record of it to prevent it happening again.
References
- MedlinePlus, U.S. National Library of Medicine. Drug reactions.
- American Academy of Dermatology. Drug eruptions.
- Mayo Clinic. Drug allergy — Symptoms and causes.
- American Academy of Allergy, Asthma & Immunology. Drug Allergies.