Urticaria
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- Localization. Trunk and extremities
- Erythematous lesion? Erythematous lesion
- Evolution time. Acute: less than 2 weeks, Recurrence
- Skin lesion. Raised: papule, plaque or nodule
- Surface texture.
- Edges Poorly defined
- Color. Due to blood: pink, red, purple or purple
- Distribution of lesions. Multiple widespread/scattered lesions, Confluent/coalescent lesions
- Associated symptoms. Itching
- Additional information.
Brief information
- Urticaria is a condition characterized by the development of wheals (hives), angioedema, or both.
- Papules:
- erythematous-pruritic appearance, typically with central pallor;
- vary in size and shape and come together;
- They are migratory, each one resolving after 30 minutes to 24 hours, giving rise to new ones, without any bruising or residual pigmentation.
- Angioedema:
- sudden and pronounced swelling, with an erythematous or skin-colored color, occurring in the lower dermis or subcutaneous tissue;
- sensation of paresthesias, burning, tightness and, sometimes, pain instead of itching;
- It resolves more slowly than papules, it can take up to 72 hours.
- Papules:
- Urticaria must be differentiated from other medical conditions involving papules, angioedema, or both such as anaphylaxis,
- autoinflammatory syndromes, urticarial vasculitis, or bradykinin-mediated angioedema.
- It can be classified according to its duration or trigger:
- Acute: occurrence of papules, angioedema or both for ≤ 6 weeks;
- Chronic: occurrence of papules, angioedema or both for > 6 weeks;
- may present daily or almost daily signs and symptoms or manifest with an intermittent/recurrent course;
- Spontaneous: occurs without a defined triggering factor.
- Inducible: occurs when a specific trigger/trigger factor is identified.
- Trigger examples include: cold, heat, pressure (late effect), sunlight, aquagenic urticaria, cholinergic urticaria (heat, exercise, or sweat), contact urticaria, or vibratory angioedema
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- Etiology
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- There are numerous potential causes of hives, although in most cases it remains idiopathic.
- Prevalence
- Women are twice as affected as men.
- Highest prevalence between 40 and 60 years of age.
Differential diagnosis
Areas exposed to pressure:
- Waist
- Armpit
- Groin
- It can affect any part of the skin.
Treatment
- 1st line treatment:
- Second generation H1 antihistamine, in a regular daily dose.
- First-generation H1 antihistamines are not routinely indicated, due to their short and long-term effects on the central nervous system.
- Consider increasing the dose of second-generation H1 antihistamine, up to 4 times the regular dose, if symptoms are not controlled with lower doses.
- Increase dose every 2–4 weeks if insufficient control.
- After complete control of symptoms, a gradual dose reduction may be attempted.
- Other options for symptomatic control include:
- Consider adding montelukast to second-generation H1 antihistamine in users whose symptoms are not adequately controlled (less evidence);
- Consider adding oral prednisolone (0.5 mg/kg) to second-generation H1 antihistamine in short, infrequent courses of just a few days as rescue treatment to control severe exacerbations.
- Second generation H1 antihistamine, in a regular daily dose.
- If symptoms are refractory to H1 antihistamines, users should be referred to a Dermatology and/or Immunoallergology consultation to start 2nd line drugs:
- Omalizumab: subcutaneous administration of 300 mg every 4 weeks.
- Cyclosporine
Chronic urticaria is generally self-limited, lasting an average of 3 to 5 years. The 12-month remission rate is 80%. Up to 14% of cases can persist for more than 5 years.