The first step in diagnosing a food allergy involves the careful review of the child’s medical history, as well as the medical histories of the parents. Children who are born into families that have a history of allergies are more likely to develop a food allergy themselves. 

The physician will also perform a physical examination to help identify or exclude medical problems that may be causing the child's symptoms. By gathering this basic information, a physician can get a better idea of where to proceed with further evaluations. This may include attempts to identify the specific allergen to which the patient is sensitive. Such procedures are not definitive, but can provide information that is relevant to the patient’s condition and useful in designing treatment plans. These measures may include:

• Skin test. This test involves pricking the child’s skin with food extracts. The tested area will react with redness or swelling to indicate an allergic reaction to the extract.
  
  

  

• RAST (radioallergosorbent test). This type of blood test allows a laboratory to directly test a blood sample from a child in an attempt to detect antibodies that correspond to specific foods.
  
  
• Oral food challenge. Different foods are placed within capsules to hide their identity. The patient consumes the capsules and the physician looks for signs of an allergic reaction. This is considered the most effective way of determining the cause of a food allergy because it supplies the most convincing results.
  
  
• Elimination diet. This diet involves removing suspect foods from a child’s diet to see if allergic reactions persist. This trial-and-error approach can take weeks before it achieves results, but it is effective at removing a problem food.

When identifying a food allergy in children or even recognizing that there is a problem, it is important to understand that a child may describe an allergic reaction in different terms than an adult. Very young children may react by placing their hands in their mouths or scratching at their tongues. Children may also slur their speech when experiencing an allergic reaction, or begin to sound hoarse or squeaky. Some specific symptoms a child might describe during an allergic reaction include:

• Hot or burning tongue
• Tingling in the mouth or tongue
• Itchiness in the tongue
• Sensation that something is stuck in the throat (or throat feels thick)
• Tongue feels heavy
• Tongue feels as if there is hair on it
• Tongue feels as if there is a bump on the back of it
• Lips feel tight
• Ears feel itchy inside
• Food is too spicy