Penicillin Allergy: Assessment, PO Challenge, & Penicillin Skin Testing

Criteria & Principles

Penicillin allergy labels are associated with increased rates of C. difficile infections, surgical site infections, VRE and MRSA infections, and increased length of stay. 80-90% of patients who report they are "allergic" to PCN actually have negative skin tests and are not at increased risk of an allergic reaction. It is our goal to improve patient care by helping remove inappropriate penicillin labels. We have a number of tools to help meet this goal. Full details are available in our attached policy but a summary is available below.

We recommend the following steps for clarifying and when appropriate, removing the penicillin allergy:

1. Perform a penicillin allergy assessment including:
   
   1. Identify and exclude patients with a non-IgE mediated allergy (These patients are NOT candidates for re-challenge)
      
      
      
      

      High Risk Allergic Reactions

      
   2. Assessing for previous tolerance of a penicillin (chart review)
2. If no high-risk contraindications identified above, calculate a PEN FAST score
   
   

   PENFAST.JPG

   
3. If PEN FAST score 0 or 1, primary team can evaluate for an oral challenge
4. If PEN FAST score 2 or greater, patient should be considered for a penicillin skin test (PST). For routine de-labeling, an outpatient consult to Allergy/Immunology can be placed. If the patient penicillin is needed during inpatient admission, consult ASET for PST consideration.

In summary:

Steps to Perform an Oral Amoxicillin Challenge to Remove a Penicillin Allergy:

1. Ensure patient does not meet exclusion criteria for oral challenge including:
   
   1. Patient <18 years of age
   2. Pregnancy
   3. History of non IgE mediated reaction as described above
   4. PEN FAST score of 2 or greater
   5. Concurrent Therapies: receipt of H1 antagonist (eg. azelastine, cetirizine, clemastine, cyproheptadine, desloratadine, doxepin, fexofenadine, hydroxyzine, levocetirizine, olopatadine) without sufficient washout or > stress dose steroids (i.e. > 50mg QID hydrocortisone [or steroid equivalent]

                     NOTE: beta blockers has been removed as an exclusion as this was not an exclusion in the PALACE trial and we are selecting for low risk patients with PENFAST scores of 0 or 1.

1. Use the ADULT Oral Amoxicillin Challenge Order Panel in Epic to order the test dose of amoxicillin and appropriate nursing orders.
   
   1. Monitoring should include vital signs every 15 minutes for 1 hour after the dose is given
   2. In the rare event of an anaphylactic reaction nursing can initiate standing orders for treatment via the DUHS orderset for Adult Hypersensitivity and Anaphylaxis Reactions pending arrival of the primary team
2. Results of the challenge must be documented by either removing the listed penicillin allergy or adding a comment that oral challenge resulted in a concerning reaction
3. Results should additionally be documented in the patient’s discharge instructions 

 

Requesting a Penicillin Skin Test

1. For routine skin testing an outpatient referral can be made using the following epic order: “Ambulatory Referral to PCN Allergy Skin Testing Clinic”
2. For patients needing a skin test on the same admission, ASET can be consulted using the following epic order: “Consult to ASET – Penicillin Skin Test”
   
   1. ASET services are available 8am-5pm Monday-Friday
   2. Patients with urgent needs or requiring desensitization should have consultation with the inpatient allergy team

 

What truly is anaphylaxis?  This image from the NIAID is very helpful in determining this diagnosis.

References

1. Blanca M, Romano A, Torres MJ, et al. Update on the evaluation of hypersensitivity reactions to betalactams. Allergy 2009;64:183-93.

2. Macy E, Contreras R. Health care use and serious infection prevalence associated with penicillin "allergy" in hospitalized patients: A cohort study. The Journal of allergy and clinical immunology 2014;133:790-6.

3. Salkind AR, Cuddy PG, Foxworth JW. The rational clinical examination. Is this patient allergic to penicillin? An evidence-based analysis of the likelihood of penicillin allergy. JAMA 2001;285:2498-505.

4. Charneski L, Deshpande G, Smith SW. Impact of an antimicrobial allergy label in the medical record on clinical outcomes in hospitalized patients. Pharmacotherapy 2011;31:742-7.

5. Sastre J, Manso L, Sanchez-Garcia S, Fernandez-Nieto M. Medical and economic impact of misdiagnosis of drug hypersensitivity in hospitalized patients. The Journal of allergy and clinical immunology 2012;129:566-7.

6. Trubiano J, Phillips E. Antimicrobial stewardship's new weapon? A review of antibiotic allergy and pathways to 'de-labeling'. Current opinion in infectious diseases 2013;26:526-37.

7. Drug allergy: A 2022 practice parameter update - Journal of Allergy and Clinical Immunology (jacionline.org)