Nokkosihottuma

Nokkosihottuma, literally translated as nettle rash, is the Finnish term for urticaria, commonly known as hives. It is a skin condition characterized by transient, itchy wheals that can appear anywhere on the body. The welts vary in size and shape, may merge, and typically fade within 24 hours, though new lesions can arise as others disappear. Angioedema, swelling beneath the skin especially around the lips or eyes, can accompany the rash.

Causes and classification: Acute urticaria is often triggered by allergic reactions to foods, medications, insect stings, or infections. Physical urticarias are triggered by stimuli such as heat, cold, pressure, vibration, or sun exposure. In many cases no trigger is found (idiopathic). Chronic urticaria lasts more than six weeks and may involve autoimmune processes.

Diagnosis: Diagnosis is primarily clinical, based on history and examination. Additional tests (blood work, specific IgE testing, or skin testing) are used selectively to identify potential triggers or associated conditions. Differential diagnoses include dermatitis, eczema, and drug eruptions.

Treatment and management: The goal is symptom relief and trigger avoidance. First-line treatment typically uses non-sedating second-generation antihistamines (for example cetirizine, loratadine, or fexofenadine). If needed, doses can be increased or combined. Short courses of oral corticosteroids may be used for acute flares. For chronic or refractory cases, options include additional antihistamines, leukotriene receptor antagonists, or biologic therapy such as omalizumab under specialist care. Skin care and patient education about triggers are important components of management.

Prognosis: Most episodes resolve within weeks; chronic urticaria affects a minority and may persist longer but is manageable with appropriate treatment.