What allergies should skin prick testing be indicated for in a patient with a family history of food and drug allergy and a sibling with a bee sting allergy?

Skin Prick Testing Indication for Stinging Insect (Bee/Wasp) Allergy

Skin prick testing is indicated for stinging insect hypersensitivity (bee stings, wasp stings, hornets, yellow jackets) when there is a history of systemic allergic reactions, regardless of family history alone. 1

When to Perform Skin Testing

Immediate hypersensitivity skin tests with stinging insect venoms are indicated for subjects who are candidates for venom immunotherapy (VIT). 1 This means:

• Testing should be performed when the patient has personally experienced a systemic reaction to an insect sting (not just because a sibling has bee sting allergy). 1
• Systemic reactions include respiratory symptoms, cardiovascular symptoms, or widespread urticaria/angioedema beyond the sting site. 1
• Testing is recommended even if the systemic reaction occurred years or decades earlier, as the risk of reaction persists for long periods. 1

Family History Alone Does Not Indicate Testing

• A family history of allergies (food, drug, or bee sting allergy in siblings) without the patient's own history of systemic reaction does NOT constitute an indication for skin prick testing. 1
• Allergy is not reliably inherited in a pattern that would justify testing asymptomatic family members. 2, 3

Testing Methodology for Insect Venom

When testing IS indicated based on personal history:

• Skin prick tests at concentrations up to 100 μg/mL should be performed before intracutaneous tests. 1
• Initial intracutaneous tests are done with venom concentrations of 0.001 to 0.01 μg/mL, increasing by 10-fold increments until positive or reaching maximum 1.0 μg/mL. 1
• Test all commercially available venoms (honeybee, yellow jacket, wasp, hornet) because the culprit insect often cannot be identified and cross-sensitization exists. 1
• Timing matters: Testing performed within 3-6 weeks after a sting reaction may yield false negatives; 79% sensitivity at 1 week increases to 100% when repeated at 4-6 weeks. 1

Food and Drug Allergy Testing Indications

For the family history of food and drug allergies mentioned:

• Skin prick testing for food allergens is indicated when there is a personal history of IgE-mediated reactions (urticaria, angioedema, anaphylaxis) occurring within minutes to 2 hours of ingestion. 2, 3, 4
• Drug allergy skin testing has limited utility and is primarily validated only for penicillin allergy; most drug reactions are not IgE-mediated and cannot be diagnosed by skin testing. 4, 5
• Family history of food or drug allergy alone does not indicate testing in an asymptomatic individual. 2, 3

Critical Pitfall to Avoid

Do not perform skin testing based solely on family history without the patient having experienced personal allergic reactions. 2, 3 This leads to:

• Unnecessary anxiety and altered lifestyle 1
• False-positive results (40-60% positive predictive value even with positive tests) 3
• Inappropriate dietary restrictions or medication avoidance 3

The diagnosis of allergy requires both positive skin testing AND correlation with clinical symptoms. 4, 5 Sensitization (positive test) does not equal clinical allergy. 4, 6, 5