The Stinging Nettle (Urtica dioica) is a common weed found in Europe, America, and some parts of Africa. Contact with the skin immediately triggers specific skin symptoms. We commonly refer to skin conditions with these symptoms as ‘Urticaria.’
Urticaria is a prevalent disease, affecting about 20% of people at least once in their lifetime!
Urticaria is characterized by transient skin and mucosal swelling due to plasma leakage. If the swelling occurs in the superficial skin, it is called ‘wheals,’ while swelling in the deeper layers of the skin or mucosa is known as ‘angioedema.’
Wheals are itchy, with a pink periphery and a pale center. Angioedema has less defined borders, often causing pain with no significant color changes.
The wheals in urticaria are temporary, usually appearing and enlarging within minutes to hours, then disappearing within 24 hours, leaving no bruises unless scratched.
Urticaria is typically painless. If skin lesions are painful or leave bruises, the diagnosis may be urticarial vasculitis.
The nomenclature of urticaria is based on its morphological appearance. The etiology and pathophysiology of urticaria are diverse.
Causes include infections, drugs, autoimmune reactions, tumors, physical stimuli, etc. Pathophysiological processes involve allergies, direct activation of mast cells, complement-mediated reactions, etc(sources from www.therapeutique-dermatologique.org).
Conventionally, urticaria recurring within six weeks is considered acute. Most cases of urticaria are acute, and distinguishing between acute and chronic is not possible at the onset.
The most common causes of acute urticaria are infections and allergies. In fact, most cases of urticaria in children are infection-related. Therefore, identifying the source of infection is crucial. Once the infection is identified, targeted treatment can control urticaria.
Recurrent episodes occurring at least twice a week and lasting for over 6 weeks are termed chronic urticaria. Most cases of chronic urticaria are spontaneous and associated with factors like autoimmunity. Identifying specific causes or triggers for chronic urticaria is challenging.
Many doctors may suggest allergy testing and avoidance of certain foods for chronic urticaria patients. However, such measures are often unnecessary because chronic urticaria is rarely allergy-induced. Even if allergies exacerbate the condition, they act as aggravating factors rather than the underlying cause. Therefore, extensive allergy testing and ‘broad-spectrum’ food avoidance are generally unnecessary.
In reality, chronic urticaria is more likely to be associated with ‘coexisting conditions’ such as thyroid diseases, celiac disease, Sjögren’s syndrome, systemic lupus erythematosus, rheumatoid arthritis, and type 1 diabetes. Due to the risk of ‘coexisting conditions,’ doctors should carefully inquire about relevant symptoms to identify any concurrent diseases.
When urticaria begins, potential triggers such as infections or allergies should be carefully sought. Treatment should address the cause, such as using anti-infective agents or eliminating allergy triggers. Additionally, antihistamine medications should be administered.
First-line treatment involves second-generation antihistamines, such as cetirizine, loratadine, or fexofenadine. If significant angioedema is present, steroid therapy may be considered. In cases of laryngeal edema, epinephrine rescue treatment may be necessary, and in severe cases, endotracheal intubation might be required. Most patients achieve control within 6 weeks. If symptoms persist beyond 6 weeks, chronic urticaria is considered.
Treating patients with chronic urticaria can be challenging, testing the patience of both the doctor and the patient. It is crucial to understand that the typical course of chronic urticaria involves 50% of patients experiencing remission within 6 months, 20% within 3 years, 20% within 5-10 years, while 2% may take up to 25 years to resolve(quotes from www.therapeutique-dermatologique.org).
Considering the characteristics of this course, the treatment approach for chronic urticaria involves:
- Avoidance of potential triggers, such as nonsteroidal anti-inflammatory drugs and factors repeatedly identified in the patient’s history.
- Standard doses of second-generation antihistamine medications. Symptom control should be maintained for at least 3 months before considering dose reduction or discontinuation.
If the standard dose of second-generation antihistamines is insufficient to control symptoms, it is recommended to treat with 2-4 times the standard dose of the same medication. Although not always supported by the drug’s instructions, the likelihood of side effects with an increased dose is generally lower compared to combined drug reactions.
If doubling the dose fails to prevent recurrent urticaria, consider combining other medications, such as first-generation antihistamines, leukotriene antagonists, and, if necessary, biologic agents targeting IgE.