Hives

Also known as urticaria, hives is a skin rash usually occurring as an allergic reaction that is marked by itching, and small pale or red swellings. It can last several hours up to several weeks.

Symptoms include:

Welt or hive formation
Blister formation
Raised heartbeat and emotional stress
Headache
Red or brown spots on the skin, typically around the chest or forehead
Diarrhoea
Itching or flushing