Food Allergy and Cow Milk Allergy Patient History
With the patient history, the physician is attempting to determine the likelihood that the patient has a
food allergy, especially a
cow milk allergy, on the basis of the symptoms, the timing of the reaction, and the food suspected of causing the reaction.
A comprehensive patient history should
include:
- Suspected allergenic foods
- Time interval from ingestion of the suspected allergenic food to onset of symptoms
- Quantity of food needed to elicit the reaction
- The most recent occurrence
- The number of occasions on which the reactions have occurred
- Association of additional factors such as exercise and concurrent medication ingestion
- Family history of food allergy or other allergic diseases
- Whether they were breast or formula fed
- Age of introduction of solids / weaning
- Any infections at the time of the reaction
It is important for the clinician to gather the following:
- Time interval from ingestion of the suspected allergenic food to onset of symptoms
This can be a valuable indication of whether the food allergy mechanism might involve IgE antibodies. IgE-mediated allergic reactions often occur within five minutes and mostly within an hour. Allergic reactions that are not mediated by IgE usually take a longer period to develop, up to 24 hours or more in some cases.
- Quantity of food required to elicit the reaction
Another indication of whether IgE may be involved in the food allergy mechanism is provided by the amount of food eliciting a reaction. Typically IgE-mediated allergic reactions can be provoked by very minimal amounts of food. In the non-IgE allergic reactions a larger amount of food (perhaps 100-200ml of cow milk) is usually ingested before a reaction is provoked.
- Number of occasions on which the reaction has occurred
It is important to find out whether the reaction was an isolated incident or whether food allergy related symptoms have been reproduced on multiple occasions.
- Association of additional factors
Sometimes other factors can influence an allergic reaction to a particular food, for example exercise. This is seen in other disorders such as food-induced anaphylaxis. Other patients will experience the food allergy symptoms only when taking certain medications such as aspirin or non-steroidal anti-inflammatory agents.
During the consultation it is also important to gather several other pieces of information such as:
- Whether the child was breast or bottle-fed
Certain conditions are more or less likely depending on the feeding method used. A child who first displayed allergy symptoms whilst being exclusively breastfed is more likely to be very sensitive / multiply allergic.
- Are medications being taken
Certain medications, such as antihistamines, can interfere with diagnostic tests. Some medicines may contain ingredients, either actives or excipients, which are causing or may contribute to allergy symptoms
- Past and current treatments
Informs the physician about which treatments have proved to be effective in the past and might allow certain diagnoses to be ruled out.
- Family history of food allergy or other allergic diseases
This is the single most important predictor of whether a child has a food allergy. 30% of food allergic infants have a parent with atopic disease, whereas 60% of infants will have a food allergy if both parents are atopic.