Cholinergic Urticaria: Triggers, Symptoms, and How Medications Can Help

When your body heats up—whether from exercise, a hot shower, or even stress—you break out in tiny, itchy bumps. That’s cholinergic urticaria, a type of hives triggered by an increase in body temperature and the release of acetylcholine. Also known as heat-induced hives, it’s not an allergy to sweat itself, but your immune system overreacting to the chemical signals that come with it. This condition affects young adults most often, and while it’s not dangerous, the burning, prickly rash can make daily activities like working out or walking in warm weather feel like a chore.

What happens inside your body is simple but messy. When your core temperature rises, your nervous system releases acetylcholine, a neurotransmitter that tells sweat glands to activate. In people with cholinergic urticaria, this same signal accidentally triggers nearby mast cells to dump histamine, a chemical that causes swelling, redness, and itching. The result? Hundreds of pinhead-sized bumps that show up within minutes, usually on the chest, neck, arms, and back. Some people also feel dizzy, nauseous, or even have trouble breathing during a bad flare-up.

Medications don’t cure cholinergic urticaria, but they can stop it from ruling your life. Antihistamines are the first line of defense—non-drowsy ones like cetirizine or loratadine taken daily can block the histamine response before it starts. For tougher cases, doctors sometimes prescribe higher doses or combine them with other drugs like leukotriene inhibitors. Avoiding triggers helps too: cooler showers, loose clothing, and pacing workouts can reduce flare-ups. But if you’re someone who breaks out every time you break a sweat, you need more than just avoidance—you need a plan.

The posts below cover real-world strategies used by patients and doctors alike. You’ll find advice on managing flare-ups with everyday meds, understanding why some antihistamines work better than others, and how other conditions like asthma or thyroid issues can make cholinergic urticaria worse. There’s no magic fix, but with the right approach, you can stop letting your body’s own heat turn your skin into a battlefield.