Answer:

Hives lasting over 6 weeks are considered chronic. Several factors can contribute to this, including allergies, individual constitution, hormones, stress, or an unusual activation of the immune system. This activation typically involves spontaneous stimulation of mast cells or the presence of autoantibodies against the high-affinity IgE receptor (FcεRI).

Some cases of chronic hives are linked to underlying conditions such as autoimmune thyroid diseases (Graves' or Hashimoto's disease), systemic lupus erythematosus, viral hepatitis, or other autoimmune disorders. However, in about 50% of cases, no specific cause can be identified even after thorough examination. These cases are classified as chronic idiopathic urticaria.

Doctor Tan consults with a patient. Photo illustration: Tam Anh General Hospital

Doctor Tan consults with a patient. Photo illustration: Tam Anh General Hospital

To determine the specific cause, you should visit a medical facility with a Clinical Immunology department for specialized tests. These may include IgE quantification (a blood test measuring IgE antibodies related to allergic reactions), allergy skin tests, thyroid function tests, or autoimmune tests.

Discontinuing previous medication or not following a doctor's instructions can mask symptoms without addressing the underlying cause. Prolonged overuse of medication can lead to dependence, reduced effectiveness, and even side effects. Self-treatment also risks overlooking more serious issues like anaphylaxis, angioedema, or autoimmune diseases.

Dr. Nguyen Phuc Tan

Clinical Immunology Department

Tam Anh General Hospital, TP HCM