Primary Care Liaison

Drug allergies

  • The following covers recommended pre-referral treatment and investigations for children of all ages presenting with a suspected medication allergy.

    Antibiotics are the most common cause of serious allergic drug reactions in children.

    • Other common agents are anaesthetic agents, NSAIDS or aspirin. Take history of drugs taken safely in the past that have not caused allergic reactions.
    • RAST and/or skin tests may be used by the specialist to investigate allergy to penicillin and penicillin derivatives, however this is only of value if the reaction is IgE mediated hypersensitivity.
    • The RAST may be falsely negative.
    • Refer to allergy specialist for further assessment if you suspect a drug reaction is allergic.

    Initial work-up


    An allergic reaction may involve one or more of the following signs and symptoms.

    Mild to moderate allergic reaction:

    • Swelling of lips, face or eyes.
    • Hives or welts.
    • Note: Maculo-papula rashes may suggest a non IgE medicated allergic reaction.

    Severe systemic allergic reaction (anaphylaxis):

    • Difficulty breathing.
    • Swelling of the tongue and/or throat.
    • Difficulty talking.
    • Hoarse voice, wheezing or persistent coughing.
    • Loss of consciousness and/or collapse.
    • Infants and young children appearing pale and floppy.

    Severe allergic reaction (anaphylaxis) will typically include multiple organ systems (ie. hives and respiratory symptoms).

    Taking a history

    • Drug - drug type, amount, form ingested.
    • Specific details of nature of reaction:
      • Timing of onset in relation to dose.
      • Duration of reaction after cessation of drug.
    • Previous or subsequent exposure to the suspected drug?


    • RAST test may be helpful for penicillin and penicillin derivatives (eg: penicillin major determinant, benzyl penicillin G, amoxycilloyl).
    • Only RAST test for drug allergy if suspect IgE-mediated reaction (not useful for non IgE mediated).
    • Skin Testing should only be performed by specialist allergist.
    • Do not attempt challenge.

    Interpretation of RAST test or SPT (Skin Prick Test)

    • Test results should be interpreted together with history.
    • Positive allergen-specific IgE (RAST or SPT) in the presence of a clear history of allergic reaction, confirms clinical allergy. Refer patient to Allergy and Immunology specialist for further management and instruct patient to avoid the specified drug.

    Pre-referral treatment

    • Discontinue the drug.
    • If alternative antibiotics are available on the market - choose one of equal efficacy.
    • Amoxicillin or penicillin-derivative reactions need avoidance of all penicillin derivative antibiotics.
    • Paracetamol can be used as an alternative to aspirin.
    • Refer to an allergy specialist.

    When to refer

    • When allergy skin tests are required.
    • When challenge testing may be required to confirm the diagnosis.
    • Where there is no other drug alternative (eg. insulin, chemotherapy or penicillin) and desensitisation is required to get the child onto the drug without causing a severe allergic reaction (transient intolerance).
    • ALWAYS refer confirmed or suspected anaphylaxis to the RCH Department of Allergy and Immunology. This is an URGENT REFERRAL.
    Do not refer:
    • For allergy screening if there is no clear history of allergic reaction - such referrals will be rejected.
    • For drug reaction if the reaction was mild, there are alternative drugs available and avoidance is an option for management (eg. Ceclor reactions).
    • When there is a family history of drug allergy and a healthy patient who has not had an allergic reaction to a drug.

    Referral information needed

    The GP at first consultation is in the best position to get the most comprehensive information from parents on the details of an allergic reaction. Please collect and include in your referral as much detail as possible. It is increasingly difficult to collect this information later.

    Information needed

    • CLEARLY INDICATE if child has confirmed or suspected ANAPHYLAXIS. The referral will be triaged as urgent.
    • Date reaction(s) occurred.
    • Allergic reaction symptoms experienced -
      • Severe systemic reaction (anaphylaxis).
      • Difficulty breathing.
      • Swelling of the tongue or throat.
      • Difficulty talking.
      • Hoarse voice, wheezing or persistent coughing.
      • Loss of consciousness and/or collapse.
      • Young children appearing pale and floppy.
    • Moderate systemic reaction -
      • Abdominal pain, vomiting.
    • Mild-Moderate reaction -
      • Swelling of lips, face or eyes.
      • Hives or welts.
    • Potential causes of reaction(s):
      • Drug - what drug/s?
    • When, where and how did the reaction(s) happen?
      • Timing of onset in relation to dose.
      • Duration after cessation of drug.
    • RAST results.
    • Treatment given and patient response.
    • Previous or subsequent exposure to allergen.

    Further information

    Please see these guidelines for further information on:

    Contact information

    Clinical advice - Page the 'on-call' Consultant or Allergy and Immunology Fellow.

    (03) 9345 5522

    Department of Allergy and Immunology:

    (03) 9345 5701
    (03) 9345 5733
    General queries and appointments

    Department of Allergy and Immunology:

    (03) 9345 4848 Fax

    RCH Emergency Department:

    (03) 9345 6477



    Booking enquiries 
    appointment rescheduling
     (Urgent bookings and for parents)

    RCH OPD referral form (word)

    Generic parent handout (about RCH pre-referral guidelines)

    Victorian Statewide Referral Form (VSRF)

    (03) 9345 6180 





    Rural doctors only

    (03) 9345 6789 

    Admission enquiries


    General admission enquiries:

    (03) 9345 6172

    ED admission enquiries:

    (03) 9345 6477

    After hours / Switchboard:

    (03) 9345 5522



    Seriously unwell child: 

    (03) 9345 7007

    RCH Drug info-line:

    (03) 9345 5208







    Copyright and Disclaimer

    Copyright 2009, Royal Children's Hospital (RCH) Victoria, Australia. The RCH is not responsible in any way for application of the procedures or guidelines to patient care at your facility. They are guidelines only and your professional judgment must always prevail. Guidelines may not be reproduced without permission. RCH Kids Connect - Primary Care   These guidelines were developed by specialists at the Royal Children's Hospital and reviewed by general practitioners in Victoria. Last reviewed April 2012.