Cross allergy (Cross-reactivity)

Cross allergy is caused by hypersensitivity to one or more substances. Cross-reactivity occurs when the proteins in one substance are like the proteins in another. As a result, the immune system sees them as the same and triggers an allergic reaction. 


Appotek can advise you on symptoms and refer you to a specialist for treatment.


Cross allergy symptoms vary depending on which allergy is triggered. It is common to get symptoms such as itching, swollen lips and throat irritation, but you can also get stomach upset, nausea, vomiting and diarrhea. Some also get hives, eczema, sneezing and itchy eyes.


Cross allergy is caused by the immune system reacting to substances that are similar to those you are already allergic to. Here are some common allergens and the cross allergies they can trigger:


Birch pollen


  • nuts
  • pear
  • plums and cherries


Grass pollen


  • peanut
  • cereals, such as oats and wheat
  • tomato


mugwort pollen


  • Curry
  • Carrot
  • pepper




  • different fruits
  • tomato
  • seafood

Prevention and Protection

Avoid foods that you notice cause a cross reaction. Be sure to check what different foods contain. Those with a pollen allergy will have more cross reactions during pollen season. Do not forget to take allergy medicine.


There are various prescription drugs that help with allergies at the pharmacy. Ask your doctor which medicine will help you best.


There are prescription drugs to treat allergies. A doctor will prescribe these after individual assessment.

When to consult a doctor

Seek care if you have major problems or if you have been treated with prescription drugs for two weeks without getting better.

How APPOTEK can help

  • Consulting
  • Individual assessment, prescriptions and referral if necessary

Vadym Diadiun, Doctor of Medicine, M.D.