Losartan Rash: Signs, What to Do, and When to Seek Help

Losartan is a common blood pressure medicine. It helps protect the heart and kidneys, and most people tolerate it well. A skin rash from losartan is not common, but it can happen. Knowing what a losartan rash looks like, when it appears, and what to do makes a big difference if it happens to you.

How a losartan rash usually looks and when it appears

Most losartan rashes are mild. You may see small red bumps, patches of itchy skin, or hives that come and go. The rash often starts days to weeks after starting the drug, but an allergic reaction can sometimes show up after longer use. Mild rashes usually stay on the skin without blistering or hurting the mouth or eyes. If the rash is widespread, rapidly spreading, or has blisters or peeling skin, that’s a red flag.

Watch for serious signs. There are rare but dangerous reactions to watch for. Angioedema causes sudden swelling of the face, lips, tongue, or throat and can block breathing. Stevens-Johnson syndrome and toxic epidermal necrolysis are severe conditions that cause widespread peeling, painful blisters, and mucous membrane damage. If you get trouble breathing, swollen face or throat, high fever with skin peeling, or painful blisters, get emergency care right away.

Quick steps if you get a rash from losartan

If you notice a mild, new rash, stop any new lotions or soaps first and take pictures of the skin. Call your doctor and describe the rash, when it started, and any other symptoms. Your doctor may ask you to stop losartan temporarily and may recommend an oral antihistamine or a short course of topical steroid cream. For mild rashes that are not worsening, some doctors may continue the medicine while treating symptoms, but only follow that if your provider agrees.

What about switching medicines? If the rash is clearly linked to losartan, your doctor will suggest an alternative. ARBs are a drug family, and some people tolerate a different ARB, while others prefer switching to a different class. If you had angioedema on losartan, your provider will pick safer options and monitor you closely.

Reporting and keeping records helps. Save photos and write down when the rash appeared and what other products or drugs you used. Report serious reactions to your health team and local adverse event system, like FDA MedWatch if you are in the United States. That helps track rare but important side effects.

Simple prevention tips: tell your doctor about past drug allergies, avoid starting several new products at once, wear sunscreen if rash is photosensitive, read labels, and check for drug interactions. If your skin reacts repeatedly, ask about referral to a dermatologist or allergy specialist for testing. Keep a short diary of medications and skin changes—this makes it easier to find the cause and prevents repeat reactions. Get help early.