Urticaria is caused due to various factors:

• Foods: such as shellfish, peanuts, tree nuts, eggs, fish, and milk are the most common culprits.
• Medications: Most common medicines that can cause hives are penicillin, aspirin, ibuprofen, naproxen, and blood pressure medications.
• Allergens: Substances that commonly cause hives are pollen, latex, animal dander, and insect stings.
• Environmental factors: Physical factors such as heat, cold, water, sunlight, pressure, exercise, and emotional stress.
• Underlying medical conditions: Certain illnesses such as thyroid conditions, bacterial and viral infections such as hepatitis, HIV, Cytomegalovirus, or Epstein-Barr virus; cancers such as lymphoma, blood transfusions, etc are also known to trigger hives.
• Psychological causes: Above all the physical causes, the most common factor we have seen in our patients is the link between major emotional disturbances with urticaria. When a patient is undergoing a major emotional setback, stress, fear, anxiety, sadness, and insecurities, the immunological state is altered which leads to hypersensitivity and urticaria.