Almond allergy works through two different pathways that require different management. The first is linked to birch pollen allergy — the immune system confuses an almond protein with birch pollen, causing tingling or itching in the mouth. Since this protein is destroyed by heat, people with this pathway can usually eat roasted almonds, almond butter, and baked goods containing almonds without problems.

The second pathway involves a heat-stable protein called LTP (lipid transfer protein) that survives roasting, baking, and digestion — people with this pathway react to all forms of almond and can experience systemic reactions. A skin prick test or component testing can distinguish between the two pathways. Almond flour and almond milk are commonly used as wheat and dairy alternatives, so hidden exposure is a real risk for people following elimination diets.