Allergic paroxysmal dyspnea

Specialty: Respiratory.

• sudden allergic shortness of breath
• acute allergic asthma
• bronchial anaphylactic dyspnea

Why it occurs

• Systemic anaphylactic reaction mediated by IgE type I (triggered by the ingestion of foods such as nuts, shellfish, Hymenoptera stings or administration of drugs, causing immediate severe bronchospasm due to mast cell degranulation and massive histamine)
• Acute massive exposure to high-density aeroallergens (such as Alternaria spores or grass pollen on stormy days, inducing sudden and intense bronchoconstriction)
• Acute occupational bronchial asthma (direct contact with isocyanates, flour or animal dander in the work environment)
• Acute hypersensitivity pneumonitis (intense exposure to silo dust or bird droppings with sudden febrile dyspnea a few hours after exposure).

Initial workup

Immediate determination of serum tryptase in the emergency room (to confirm active anaphylaxis); analytical arterial blood gas; Immediate reading skin tests (Prick test) or quantification of specific IgE against suspected allergens (performed once the acute phase has passed); Spirometry with bronchodilator test.

Standard management

• Adrenaline — formulation 1:1000, dose of 0.3-0.5 mg by deep intramuscular route in the anterolateral aspect of the thigh immediately when anaphylaxis is suspected with respiratory or hemodynamic compromise
• Methylprednisolone — 40-80 mg intravenously immediately
• Dexchlorpheniramine — H1 antihistamine, 5 mg intravenously or slowly intramuscularly
• Salbutamol (nebulized, 5 mg diluted in saline solution).