Physical triggers

A physical factor other than an allergen can cause hives.

Here are some possible triggers:

• sunlight exposure
• scratching or rubbing the skin
• pressure, from a tight belt, for example
• extreme temperatures or changes in temperature
• a high body temperature, due to sweating, exercise, anxiety, or a hot shower
• adrenalin, which the body releases during exercise and exposure to heat or stress
• UV light from a tanning bed
• water on the skin, in rare cases
• vibration, in rare cases