When can a patient with anaphylaxis be considered for discharge?

From the Guidelines

A patient with anaphylaxis can be considered for discharge after a minimum observation period of 4-6 hours following symptom resolution and treatment, as recommended by the most recent guidelines 1. Discharge is appropriate when symptoms have completely resolved, vital signs are stable, and the patient has no signs of biphasic reaction (recurrence of symptoms). Prior to discharge, patients should receive prescriptions for an epinephrine auto-injector, a 3-5 day course of oral antihistamines, and oral corticosteroids if indicated. Patients must receive clear discharge instructions including how and when to use the epinephrine auto-injector, the importance of seeking immediate medical attention after using it, and avoidance of identified triggers. A follow-up appointment with an allergist should be arranged within 1-4 weeks. Some key points to consider when deciding on discharge include:

• The severity of the initial anaphylaxis presentation
• The need for multiple doses of epinephrine
• The presence of underlying medical conditions, such as asthma or cardiovascular disease
• The risk of biphasic anaphylaxis, which can occur in up to 20% of anaphylaxis cases, typically within 8-12 hours of the initial reaction 1. Longer observation periods (12-24 hours) may be necessary for patients with severe reactions or those at higher risk for biphasic anaphylaxis. The most recent guidelines suggest that extended observation should be considered for patients with a severe initial presentation of anaphylaxis or those who require multiple doses of epinephrine 1. It is also important to note that the optimal duration of observation is not clearly defined, and the decision to discharge should be made on a case-by-case basis, taking into account the individual patient's risk factors and medical history 1. In general, a cautious approach is warranted, and patients should be closely monitored for signs of biphasic anaphylaxis before discharge. The use of shared decision-making tools may also be helpful in determining the optimal observation period for each patient 1. Ultimately, the decision to discharge a patient with anaphylaxis should be based on a thorough assessment of their individual risk factors and medical history, as well as their response to treatment.

From the Research

Discharge Criteria for Anaphylaxis

To determine when a patient with anaphylaxis can be considered for discharge, several factors must be taken into account, including the severity of the reaction, the presence of risk factors for severe anaphylaxis, and the time course of the reaction.

• The patient should be monitored for a period of time to ensure that no biphasic reaction occurs, which is a recurrence of anaphylaxis without reexposure to the allergen 2, 3, 4.
• The observation period can vary depending on the individual case, but it is generally recommended to observe patients for 4 to 12 hours after the onset of symptoms, or even up to 24 hours in some cases 2, 3, 4.
• Patients with severe anaphylaxis, coexisting asthma, mast cell disorders, older age, underlying cardiovascular disease, peanut and tree nut allergy, and drug-induced reactions may require longer observation periods 2.
• Children under 16 years should be admitted and supervised by a paediatrician 5.
• Before discharge, patients should be provided with an emergency action plan, referred to an allergist, and educated on avoidance of triggers and appropriate use of an epinephrine auto-injector 2, 5.

Observation Period

The optimal observation period after anaphylaxis is not well established, but most studies recommend observing patients for at least 6-12 hours after the onset of symptoms 5, 4.

• Some investigators recommend a 10-hour observation period, while others suggest 24 hours 4.
• The decision to discharge a patient should be individualized based on the specific circumstances of the case, including the severity of the reaction and the presence of risk factors for severe anaphylaxis 2, 4.

Role of Corticosteroids

Corticosteroids are commonly used in the emergency treatment of anaphylaxis, but their role in preventing biphasic anaphylaxis is not well established 6.

• Some studies suggest that corticosteroids may not be effective in preventing biphasic anaphylaxis, and their use should be individualized based on the specific circumstances of the case 6.