Sesame Allergy

Sesame allergy is an IgE-mediated reaction to sesame seed proteins. It has become more frequent, often causes severe reactions, and persists in most patients.

Pathophysiology. Major allergens are the 2S albumin Ses i 1, the 7S globulin Ses i 3 and the 11S globulin Ses i 6, which are heat stable. Sesame sensitisation may follow skin exposure through sesame oil in eczematous skin.

It affects roughly 0.2 to 0.5% of the population in some countries. Only a minority outgrow it, and children with high specific IgE are least likely to.

Sesame is present in many processed foods, such as bread, burger buns, hummus (tahini), halva, falafel, dressings and spice blends, and its presence may not be obvious.

• Urticaria, angio oedema, flushing
• Vomiting, abdominal pain, diarrhoea
• Wheeze, cough, throat tightness
• Anaphylaxis, which is relatively common
• Contact reactions from skin products with sesame oil
• Frequent coexistence with peanut and tree nut allergy

• History: food, hidden sources, amount, timing and severity.
• Skin prick test and specific IgE to sesame and Ses i 1: a wheal of 8 mm or more, or specific IgE over 7 kU/L, makes a clinical reaction likely, but sensitisation without reaction is also common.
• Supervised oral food challenge to confirm allergy or resolution, and especially in sensitised patients with no clear history.
• Assessment of coexisting peanut and tree nut sensitisation.

Differential diagnosis.

• Peanut allergy and tree nut allergy
• Other seed allergy (poppy, sunflower, mustard)
• Pollen food allergy syndrome
• Food intolerance
• Idiopathic anaphylaxis
• Contact dermatitis from sesame oil

• Strict avoidance of sesame seed, tahini and sesame oil. Read labels for sesame, tahini, benne seed, gingelly and til.
• Adrenaline auto injector: 150 microgram for 7.5 to 25 kg, 300 microgram for 25 to 50 kg, 500 microgram for over 50 kg, with a written action plan and training of carers and school.
• Anaphylaxis: adrenaline 0.01 mg/kg intramuscularly (maximum 0.5 mg; 0.5 mg in adults) into the anterolateral thigh, repeated after 5 minutes if no improvement, plus oxygen and intravenous fluids, and observation for at least 6 hours.
• Mild reactions: cetirizine (children 1 to 5 years 2.5 mg twice daily; 6 to 11 years 5 mg twice daily; over 12 years and adults 10 mg once daily).
• Asthma control is optimised, since asthma raises the risk of severe reactions.
• Early introduction of well cooked sesame (tahini paste mixed in food) is considered in infants at risk of food allergy.
• Sesame oral immunotherapy is experimental and performed only in specialist centres.
• Skin products: avoid creams and cosmetics containing sesame oil in eczematous skin.

Special groups.

• Children with peanut or tree nut allergy: check sesame sensitisation, since coexisting allergy is frequent.

Monitoring. Review every 6 to 12 months. Repeat skin prick or specific IgE every 1 to 2 years in children. Check auto injector dose and expiry.

Referral and escalation. Refer to allergy for any suspected sesame reaction. Emergency for anaphylaxis.