An urticarial rash, also known as hives, is characterized by swelling of the skin's surface into red or skin-colored welts (wheals) with clearly defined edges. These wheals are a hallmark of the condition.
Understanding Wheals
Wheals are raised, itchy bumps or patches of skin that are typically:
- Red or skin-colored: The color can vary based on skin tone and the underlying cause.
- Well-defined: They have clear, distinct borders.
- Transient: Individual wheals often change shape, disappear, and reappear within minutes or hours in different locations on the skin.
- Variable in size: They can range from small spots to large, confluent areas.
Characteristics of an Urticarial Rash
Beyond the presence of wheals, an urticarial rash exhibits the following features:
- Itchiness (Pruritus): Intense itching is a common symptom.
- Changing Pattern: The rash can spread, with individual wheals merging to form larger areas of raised skin. Existing wheals may fade while new ones appear elsewhere.
- Short Duration of Individual Wheals: A single wheal typically lasts less than 24 hours.
Causes of Urticaria
Urticaria can be triggered by a variety of factors, including:
- Allergens: Foods, medications, insect stings, and latex are common allergens.
- Infections: Viral, bacterial, or fungal infections.
- Physical Stimuli: Pressure, temperature changes (heat or cold), sunlight, or exercise.
- Medical Conditions: Certain autoimmune diseases or thyroid disorders.
- Stress: Emotional stress can sometimes trigger or worsen urticaria.
Diagnosis and Treatment
Diagnosis usually involves a physical exam and a review of the patient's medical history. Allergy testing may be performed to identify specific triggers.
Treatment options include:
- Antihistamines: To relieve itching and reduce the formation of wheals.
- Corticosteroids: In more severe cases, oral or topical corticosteroids may be prescribed.
- Epinephrine: For severe allergic reactions (anaphylaxis) that cause breathing difficulties.
- Trigger Avoidance: Identifying and avoiding known triggers is crucial for preventing future outbreaks.
