Losartan rash: how to spot it and what to do

Took losartan and noticed an itchy patch or red bumps? A skin reaction can happen with many meds, including losartan. Most of the time it's mild and fixable, but some signs mean you need quick medical help. Here’s a plain, practical guide to recognize a losartan rash, decide what to do next, and talk to your doctor without panic.

What a losartan rash looks like and when it shows up

Rashes from losartan usually appear as red bumps, raised patches, or widespread itching. They can start anywhere—torso, arms, legs, even the face. Timing varies: some people notice symptoms within days of starting the drug; others only after a few weeks. If the rash comes with fever, mouth sores, or peeling skin, that’s a red flag for a serious reaction and needs immediate care.

There’s also angioedema to be aware of. While more common with ACE inhibitors, angioedema (swelling of the face, lips, tongue, or throat) has been reported with ARBs like losartan. If you have any swelling that affects breathing or swallowing, call emergency services right away.

Simple steps to take if you get a rash

1) Don’t stop medication silently if your doctor hasn’t told you to—unless the rash is severe or you have breathing trouble. Mild rashes can be managed while you contact your prescriber. 2) For mild itching or small patches, try over-the-counter antihistamines (like cetirizine or loratadine) and a fragrance-free moisturizer. A short course of a topical steroid cream can help but check with your pharmacist or doctor first. 3) Take photos of the rash so you can show your clinician how it looked and whether it changed.

If the rash is spreading fast, causing fever, painful blisters, or involves mucous membranes (mouth, eyes, genitals), stop losartan immediately and seek emergency care—these could be signs of Stevens-Johnson syndrome or another severe reaction.

When you contact your doctor, they may advise stopping losartan and switching to another blood-pressure drug. Alternatives include calcium-channel blockers (like amlodipine), thiazide diuretics, or beta blockers, depending on your health needs. Don’t switch on your own—decisions should be made with a clinician.

Allergic testing for losartan is rarely done, but your doctor may refer you to an allergist if the reaction was unclear or serious. Note: cross-reaction between ACE inhibitors and ARBs is uncommon, but your doctor will choose a safe alternative based on your history.

Bottom line: most losartan rashes are mild and manageable, but any sign of swelling, breathing trouble, blistering, or fever needs urgent care. Keep records (photos and timing), tell your prescriber, and follow their plan for stopping or switching medication.