Wheals: Causes, Symptoms and Treatment

What Are Wheals?

Wheals are transient, raised, and typically intensely itchy swellings of the skin. They are a hallmark feature of urticaria (commonly known as hives) and allergic reactions. The skin develops reddish or pale, slightly elevated areas that can form within minutes and usually resolve within 24 hours without leaving a mark.

Wheals may appear as single lesions or in large numbers across the body. They are a common presentation in dermatology and allergology.

Causes

Wheals form as a result of histamine and other mediators being released from mast cells in the skin. Common triggers include:

• Allergic reactions: Insect stings, foods (e.g., nuts, fish, strawberries), or medications (e.g., penicillin, aspirin)
• Physical stimuli: Pressure, cold, heat, sunlight, or friction on the skin
• Infections: Viral or bacterial infections can trigger wheals
• Chronic conditions: Thyroid disorders, autoimmune diseases
• Stress and psychological factors
• Idiopathic causes: In many cases no clear trigger is identified (idiopathic urticaria)

Symptoms

The characteristic features of wheals include:

• Raised, well-defined skin swellings (papules or plaques)
• Redness (erythema) or a pale center with a red surrounding halo
• Intense itching, sometimes accompanied by a burning sensation
• Transient nature: individual wheals typically resolve within 24 hours but may reappear elsewhere
• Possible associated reaction: angioedema (deeper swelling beneath the skin, e.g., of the lips, eyelids, or tongue)

Diagnosis

Diagnosis of wheals is primarily clinical, based on visual assessment of the skin. Additional investigations may include:

• Medical history: Detailed questioning about triggers, duration, and associated symptoms
• Allergy testing: Skin prick test, intradermal test, or specific IgE blood tests
• Blood tests: Inflammatory markers, thyroid function tests, autoantibodies
• Provocation tests: For suspected physical urticaria (e.g., cold challenge test)

Treatment

Treatment depends on the underlying cause and severity of the condition:

Acute Management

• Antihistamines (e.g., cetirizine, loratadine) are the first-line treatment to relieve itching and swelling
• For severe reactions: Corticosteroids (e.g., prednisolone) to suppress the inflammatory response
• In cases of anaphylaxis with angioedema: Immediate administration of adrenaline (epinephrine)

Long-Term Management and Prevention

• Identification and consistent avoidance of known triggers
• For chronic urticaria: Regular use of antihistamines or the biologic agent omalizumab
• Stress reduction and lifestyle adjustments
• Allergy identification card and emergency kit (adrenaline auto-injector) for those at risk of severe reactions

When to See a Doctor

If wheals are accompanied by difficulty breathing, swallowing problems, swelling of the face or throat, or a sudden drop in blood pressure, immediate medical attention is required, as these may indicate a life-threatening anaphylactic reaction. Persistent or frequently recurring wheals lasting more than 6 weeks should also be evaluated by a healthcare professional.

References

1. Zuberbier T. et al. - The EAACI/GA2LEN/EDF/WAO Guideline for the Definition, Classification, Diagnosis and Management of Urticaria. Allergy, 2022.
2. Deutsche Dermatologische Gesellschaft (DDG) - Guideline on Urticaria, AWMF Register No. 013-028, 2022.
3. Kaplan AP - Chronic Urticaria: Pathogenesis and Treatment. Journal of Allergy and Clinical Immunology, 2004.