Based on NIH | Can losartan cause a skin rash, and what should I do if I develop one?

Yes, losartan can cause skin rashes in some people. Rash, itching, hives, and photosensitivity (sun‑sensitive skin reactions) have been reported with losartan and similar angiotensin II receptor blockers (ARBs). ^[1] Rash and pruritus are listed among common skin side effects on consumer and professional labels for losartan. ^{[2] [3]} Photosensitivity reactions skin reactions triggered or worsened by sunlight have been described with losartan and may occur across the ARB class. ^[4]

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How common is a rash with losartan?

In clinical studies of the losartan/hydrochlorothiazide combination (Hyzaar), rash was reported in about 1.4% of users, though rates can vary by study and population. ^{[5] [6]} While most rashes are mild, more serious allergic-type reactions (like hives with swelling or angioedema) have been rarely reported. ^[1] Severe reactions such as anaphylaxis have been described in case reports, but they are uncommon. ^[7]

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What does a losartan-related rash look like?

• Typical rash: It may appear as red, flat or slightly raised patches (maculopapular) and can be itchy. ^[2]
• Hives (urticaria): Raised, itchy welts that can move around. ^[1]
• Photosensitivity: Redness, discoloration, or sunburn-like reactions on sun-exposed skin after light exposure. ^[4]
• Angioedema: Swelling of the face, lips, tongue, or throat, sometimes with hives this is an emergency. ^[8]

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What should you do if you develop a rash?

• Stop and call for medical advice promptly: Product guidance advises stopping the drug and contacting a clinician if any type of rash develops, especially if there are blisters, fever, or signs of hypersensitivity. ^{[9] [10]}
• Seek emergency care for serious signs: If there is swelling of the face, lips, tongue, or throat, trouble breathing, or widespread hives with dizziness, get emergency help and discontinue losartan right away. ^[8]
• Supportive care for mild rash: Mild rashes often improve within days after dose reduction, short-term antihistamines, and/or stopping the medication, under clinical guidance. ^[9]
• Sun protection for photosensitivity: Limit sun exposure, use broad-spectrum sunscreen, wear protective clothing, and discuss whether to hold or switch the medication. ^[4]

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Could it be something else?

Rashes have many possible causes other medicines, infections, contact allergens, or underlying skin conditions so it is important to review all current drugs and exposures with your clinician. A careful evaluation helps determine if losartan is the likely cause and whether a switch is needed. ^{[1] [2]}

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When to stop losartan versus continue

• Stop immediately and seek care if there are signs of an allergic reaction (facial/lip/throat swelling), extensive hives, blistering, fever, or mucous membrane involvement. These may signal angioedema or severe cutaneous reactions and need urgent assessment. ^{[8] [11]}
• Consider pausing and calling your clinician for new, mild, non-severe rash or itch; many cases resolve after stopping or adjusting therapy and using short-term antihistamines. ^[9]
• Do not restart if a clinician confirms a serious hypersensitivity reaction attributable to losartan. ^[8]

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What are the risks of severe skin reactions?

Serious skin reactions like Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare but life-threatening, characterized by blistering, peeling, and mucosal involvement; immediate drug withdrawal and hospital-level care are essential. While extremely uncommon with ARBs, awareness and early action are critical. ^{[11] [12]}

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Are there alternatives if rash occurs?

If losartan is suspected to cause a rash, clinicians can consider switching to another antihypertensive, such as a different ARB or another class (e.g., calcium channel blocker or thiazide diuretic), based on your medical profile. Photosensitivity appears possible across the ARB class, so your clinician will weigh risks and benefits when choosing alternatives. ^[4]

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Practical steps you can take

• Document the rash: Note when it started, what it looks like, whether it itches, and any new medications or sun exposure. Share photos if possible.
• Protect your skin from sun: Use SPF 30+ sunscreen, reapply frequently, and wear hats/long sleeves if you notice sun sensitivity. ^[4]
• Avoid self-restarting: If a rash resolved after stopping losartan, do not restart without medical guidance. ^[9]
• Follow up: Your clinician may recommend antihistamines, topical steroids for itch/inflammation, and lab checks if severe symptoms occur. ^[9]

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Key takeaways

• Losartan can cause rash, itch, hives, and sun-sensitive reactions; most are mild and reversible. ^{[1] [2] [4]}
• Stop the drug and get immediate help for swelling of the face/lips/tongue, breathing trouble, blistering, or fever. ^[8]
• Work with your clinician to confirm the cause and choose safe alternatives if needed. ^{[9] [4]}

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Quick reference: Skin reactions linked to losartan

Reaction type	Typical features	Urgency	Usual action
Mild maculopapular rash/itch	Red patches, mild itch	Prompt medical advice	Consider stopping/adjusting medication; short-term antihistamines; reassess BP plan. [9] [2]
Hives (urticaria)	Raised itchy welts	Prompt medical advice; urgent if widespread with swelling	Stop drug; antihistamines; evaluate for allergy; consider alternative therapy. [1]
Photosensitivity	Redness/discoloration on sun-exposed skin	Prompt medical advice	Sun protection; consider drug switch if persistent. [4]
Angioedema/anaphylaxis	Facial/lip/tongue/throat swelling, breathing issues	Emergency	Stop drug; emergency treatment; do not restart. [8] [7]
Severe blistering (SJS/TEN)	Blisters, peeling, mucosal ulcers, fever	Emergency	Immediate discontinuation; hospital care. [11] [12]

If you’re unsure whether your rash is related to losartan, contacting your clinician promptly is the safest approach. ^[9]