Acute Urticaria

- Acute urticaria is more likely than chronic urticaria to have an identifiable cause, which may include [1]:

• Foods

  • Top 8 food allergens: dairy, egg, wheat, peanut, tree nut, sesame, fish, shellfish

  • Food additives: less common – carmine, annatto, erythritol, guar gum [6]

• Drugs: multiple mechanisms

  • IgE-mediated: NSAIDs, anti-microbials

  • Direct mast cell activation: opioids, vancomycin, contrast, muscle relaxants, NSAIDs

  • Serum-sickness, serum sickness-like reactions

• Latex

• Hormones: oral contraceptives, hormone replacement therapy, endogenous (cyclic – autoimmune progesterone dermatitis)

• Contact urticaria: animal saliva, raw foods, other topicals (rare, more commonly cause contact dermatitis [7]) [8]

• Scromboid

• Blood products

• Venom: bee, wasp, hornet & fire ant stings; triatoma

• Physical urticaria: dermographism, solar, cold, aquagenic, vibratory, delayed pressure, cholinergic, heat, posture

• Immune system activation:

  • Vaccination [9]

  • Infection (especially in pediatrics) [10]

  • Viral: parvovirus B19, herpesviruses (CMV, EBV), rhinovirus, hepatitis (A, B, and C), HIV, coronavirus (including Covid-19) [11, 12]

  • Bacterial: Mycoplasma pneumoniae [13], UTIs, Chlamydia pneumoniae, Helicobacter pylori [10]

  • Parasitic: usually prominent eosinophilia; Schistosoma, Blastocystis, Anisakis, Ancylostoma, Strongyloides, Filaria, Echinococcus, Trichinella, Toxocara

  • May have multiple triggers and/or need for multiple triggers to be present at the same time (ex. food-dependent and/or exercise-induced phenomena [14-16])

• Systemic disorders: involvement of additional systems (pulmonary, cardiovascular, gastrointestinal, hematologic, neuropsychiatric) [1, 4]

  • Vasculitis (urticaria, cutaneous small vessel): lesions can be painful and longer-lasting (> 24H) with residual dyspigmentation

  • Mastocytosis

  • Allergic bronchopulmonary aspergillosis (ABPA)

  • Rheumatologic: systemic lupus erythematosus, rheumatoid arthritis, Sjogren’s disease, juvenile idiopathic arthritis, Still’s disease, celiac disease, Henoch-Schonlein purpura, eosinophilic granulomatosis with polyangiitis (EGPA)

  • Malignancy

  • Gleich syndrome