For acute (duration less
than 6 weeks) urticaria, the main possible precipitating agents are:

·        
Recent illness

·        
Medication use

·        
IV radiocontrast media

·        
Travel

·        
Foods

·        
New perfumes, hair dyes,
detergents, lotions, creams, or clothes

·        
Exposure to new pets
(dander), dust, mold, chemicals, or plants

·        
Contact with nickel,
rubber, latex, industrial chemicals, and nail polish

·        
Sun or cold exposure

·        
Exercise

·        
Alcohol ingestion

 Symptoms of urticaria can last from
minutes to months - or even years, in case it becomes chronic, but it is
usually a self-limited condition.

Urticaria has the appearance of large bug bites that are
characterized by the following:

They
can appear on any area of the body; their shape may change and jump from one area to another, disappear and reappear over short periods of time.

The
bumps - red or skin-colored “wheals” with clear edges - usually appear suddenly
and go away just as quickly.

Pressing
the center of a red hive makes it turn white - a process called “blanching.”

Even with treatment, this
rash may still persist for a few days before it resolves.