Urticaria

Urticaria, commonly known as hives, is a skin condition characterized by raised, itchy welts that can vary in size and appear anywhere on the body. It’s often accompanied by angioedema, swelling beneath the skin.

Causes

  • Allergic Reactions: To foods, medications, insect stings, or other allergens.
  • Infections: Viral infections, particularly in children, can trigger urticaria.
  • Physical Stimuli: Such as pressure, temperature changes, sunlight, or exercise.
  • Stress: Emotional stress can exacerbate or trigger hives.
  • Autoimmune Disorders: Where the body’s immune system attacks its own tissues.
  • Medications: Such as NSAIDs, antibiotics (especially penicillin and sulfa drugs), and ACE inhibitors.
  • Underlying Health Conditions: Thyroid disease, lupus, or other autoimmune diseases.
  • Idiopathic: In many cases, the exact cause of urticaria is not identified.

Diagnosis

  • Medical History: Assessment of symptoms, potential triggers, duration, and any associated symptoms (like difficulty breathing).
  • Physical Examination: Noting the appearance of the hives and any associated angioedema.
  • Allergy Testing: Skin prick tests or blood tests to identify potential allergens.
  • Blood Tests: To check for underlying conditions, especially if chronic urticaria is suspected.
    • Full Blood Count (FBC): To check for signs of infection, anemia or eosinophilia
    • Erythrocyte Sedimentation Rate (ESR) and
    • C-Reactive Protein (CRP): These are markers of inflammation in the body and can be elevated in chronic urticaria, especially if it’s autoimmune-related.
    • Thyroid Function Tests: Including TSH, Free T3, and Free T4, to rule out thyroid disorders, as autoimmune thyroid disease can be associated with chronic urticaria.
    • Autoimmune Antibodies:
      • Antinuclear Antibody (ANA): To check for autoimmune disorders like lupus or rheumatoid arthritis.
      • Thyroid Autoantibodies: Such as anti-thyroid peroxidase antibodies
    • Liver Function Tests: To evaluate liver health, as liver diseases can sometimes present with skin manifestations like urticaria.
    • Serum Immunoglobulin E (IgE): Elevated in allergic conditions.
    • Allergy Testing: Specific IgE blood tests for common allergens, if an allergic cause is suspected.
    • Complement Levels: Particularly C1 inhibitor levels, to rule out hereditary angioedema, especially if the urticaria is accompanied by recurrent angioedema.
    • Infectious Disease Serologies: Depending on the patient’s history and exposure risks, tests for infections like hepatitis, Helicobacter pylori, and HIV may be considered.
    • Stool Analysis: In cases where a parasitic infection is suspected.
    • Serum Tryptase: Elevated levels can be seen in systemic mastocytosis, a rare condition associated with urticaria.
    • Skin Autoantibodies: In cases of suspected autoimmune urticaria.
  • Challenge Tests: Occasionally used if a reaction to food or medication is suspected.

Differential Diagnosis

  • Contact Dermatitis: Reaction to skin contact with an allergen.
  • Drug Eruptions: Skin reactions to medications.
  • Insect Bites and Stings: Can cause localized swelling and itching.
  • Autoimmune Disorders: Such as systemic lupus erythematosus.
  • Mastocytosis: A disorder involving excessive mast cells, can mimic chronic urticaria.

Management

  • Acute Urticaria
    • Antihistamines: First-line treatment to relieve itching and swelling. Newer, non-sedating antihistamines are preferred.
    • Avoiding Triggers: If identified, avoiding known allergens or triggers.
    • Cool Compresses: To ease itching.
  • Chronic Urticaria
    • Higher Dose Antihistamines: Often required for effective control.
    • Leukotriene Modifiers: Such as montelukast, particularly if antihistamines are not fully effective.
    • Immunosuppressants: For severe cases unresponsive to other treatments, drugs like cyclosporine may be used.
    • Omalizumab (Xolair): An injectable medication used for chronic urticaria unresponsive to antihistamines.
  • Identifying and Managing Underlying Conditions: Especially in cases of suspected autoimmune or thyroid disorders.
  • Lifestyle and Home Remedies
    • Stress Management: Techniques like yoga, meditation, or counseling.
    • Dietary Considerations: Avoiding foods known to cause histamine release in some individuals, such as alcohol, aged cheeses, and processed meats.

Conclusion

Urticaria management primarily involves symptom relief through antihistamines and identifying and avoiding triggers. Chronic urticaria may require more extensive treatment, including higher-dose medications or immunosuppressants. It’s also important to investigate and manage any underlying conditions. Regular follow-up is recommended, especially in chronic cases, to adjust treatment strategies as needed.