Chronic Spontaneous Urticaria (CSU) is a persistent skin condition characterized by the sudden appearance of hives, also known as welts or wheals, on the body. This condition is considered “spontaneous” because the hives emerge without a clear external trigger. Living with CSU can significantly affect daily life due to the unpredictable and often uncomfortable nature of the symptoms.
Understanding Chronic Spontaneous Urticaria
CSU is a form of chronic hives that persist for six weeks or longer, with new outbreaks occurring at least three to four times per week. Unlike acute urticaria, which often has identifiable causes, CSU lacks a clear external trigger for its onset. The condition is sometimes referred to as chronic idiopathic urticaria (CIU), with “idiopathic” signifying an unknown cause.
It affects approximately 0.5% to 1% of the general population worldwide. It can affect individuals of any age, including children, but is most commonly observed in adults between 20 and 40 years old, with women being affected about twice as often as men. While the exact cause remains unknown in many cases, it is believed to involve the activation of mast cells in the skin, leading to the release of histamine and other inflammatory mediators.
Recognizing the Signs and Symptoms
The primary signs and symptoms of CSU involve the appearance of hives and, in many cases, angioedema. Hives are raised, itchy welts that can be red or skin-colored, varying in size. These lesions can appear anywhere on the body and typically blanch, or turn white, when pressure is applied.
Hives in CSU are characterized by their transient nature, often disappearing within 24 hours in one area only to reappear elsewhere on the body. The intense itching associated with these hives can disrupt daily activities and sleep.
A significant number of individuals with CSU also experience angioedema, which is a deeper swelling of tissues. This swelling most commonly affects areas like the eyes, lips, genitals, hands, or feet, and may cause a burning sensation or pain rather than itchiness.
How CSU is Diagnosed
Diagnosing CSU primarily relies on a thorough clinical assessment by a healthcare provider. The diagnosis is made when a person experiences recurrent hives for more than six weeks without an identifiable external cause. A doctor will typically take a detailed medical history, inquiring about the onset, frequency, size, and distribution of the hives, as well as any associated symptoms like angioedema. A physical examination is also performed to observe the characteristics of the skin lesions. While CSU is not typically caused by allergies, blood tests or allergy tests may be conducted to rule out other underlying conditions or to identify rare triggers if the urticaria is not truly spontaneous.
Managing and Treating CSU
Managing CSU aims to control symptoms and improve the individual’s quality of life, as there is currently no cure for the condition. First-line treatment typically involves non-drowsy H1-antihistamines, which work by blocking histamine release and reducing itching and swelling. If standard doses are insufficient, healthcare providers may increase the dosage up to four times the usual amount.
For individuals who do not respond adequately to antihistamines, second-line treatments are considered. Omalizumab, an injectable biologic medication, is often the next step. It works by targeting immunoglobulin E (IgE), an immune system protein, thereby reducing the release of inflammatory mediators from mast cells. This treatment is typically administered as a subcutaneous injection every four weeks.
If symptoms persist despite antihistamines and omalizumab, immunosuppressants such as cyclosporine may be considered. Cyclosporine reduces the immune system’s activity and can be effective in patients who have not responded to previous therapies. Other potential therapies include lifestyle adjustments, such as avoiding known aggravating factors. Working closely with a dermatologist or allergist is helpful to develop an individualized treatment plan and explore suitable options.