These are signs that your child may have an allergy:

 
• Irritated, red, itchy eyes;  
• Repeated sneezing: Children also sneeze when they have colds, but is more commonly associated with allergies;  
• A runny nose, with clear, watery discharge, not thick, yellow and green;  
• So-called allergic shiners, or dark rings under the eyes;  
• So-called clucking - kids with allergies often click on the roofs of their mouths with their tongues;  
• The so-called allergic salute: Kids with allergies develop a habit of frequent, upward rubs with their mouths. This causes the development of an allergic crease, or a line across the bridge of the nose.

In summary, the differences are:

A cold:

 
• Usually begins with or is accompanied by a sore throat;  
• Generally doesn’t last more than ten days;  
• Usually occurs during winter months;  
• The child usually complains about the symptoms;  
• Can include a fever;  
• Family members may also be ill;

A seasonal allergy:

 
• The symptoms disappear when the child moves from one environment to another, signaling that they’ve moved away from the allergy trigger;  
• The symptoms can be ongoing;  
• Is more serious during spring and summer;  
• There is usually no fever;  
• The child might not complain abut feeling unwell, even though the symptoms are present;  
• Symptoms such as itchy, watery eyes, ticklish throat and sneezing are present.