Allergic reactions are unusually scary because they can change quickly and they often happen in the evening — after a new food, a new medication, a bite picked up earlier in the day. The good news is that grading them is straightforward once you know the three tiers. The hard part is doing it calmly while it's happening to you.
The three-tier grading
Mild — manageable at home
- Hives (raised, itchy red or pale welts) confined to one area or scattered
- Mild itching
- Local swelling at the site of contact (e.g. one finger after touching a plant)
- Sneezing, runny nose, mild watery eyes
- No swelling of lips, tongue, face or throat
- No breathing change, voice change, dizziness
Action: Take a long-acting antihistamine (cetirizine, loratadine, fexofenadine). Apply a cold compress for itch. Avoid the trigger. Most mild reactions settle within 6 hours.
Moderate — same-night assessment
- Swelling of lips, eyes or face (angioedema)
- Widespread hives covering large parts of the body
- Generalised itching across the whole body
- Mild abdominal cramps, nausea or vomiting after a known allergen
- Recurrent reactions that have escalated over the day
Action: Take an antihistamine if you can swallow tablets. Walk in to Manningham After-hours Emergency Care or phone us first. We have prednisolone (oral steroid), additional antihistamine, and the equipment to monitor your vital signs and intervene if your reaction escalates.
Severe — call 000 immediately
Any of the following is anaphylaxis:
- Difficulty breathing, wheeze, noisy breathing or shortness of breath
- Swelling of the tongue or throat that affects swallowing or breathing
- Hoarse voice or change in voice
- Persistent dizziness or fainting
- Pale and floppy (in young children)
- Persistent vomiting after a known allergen
- Collapse or loss of consciousness
If you have an EpiPen, use it now, even if you're not sure. There is no harm in unnecessary adrenaline; there is real harm in delayed adrenaline. Call 000. Lie flat. Stay still.
What anaphylaxis actually looks like
Anaphylaxis has two essential features: it involves more than one body system (skin and breathing, or skin and circulation), and it progresses fast. A simple hives reaction doesn't change much over an hour. Anaphylaxis can go from "I think I'm reacting" to "I can't breathe" in under five minutes.
The mistake people make is waiting to see if the reaction settles. With anaphylaxis, every minute without adrenaline is a minute the airway can swell further. The EpiPen is designed for use during uncertainty.
When an antihistamine is enough
For pure cutaneous (skin-only) reactions, antihistamines work well. Use a non-sedating, long-acting one: cetirizine 10 mg, fexofenadine 180 mg, or loratadine 10 mg. Avoid older sedating antihistamines (promethazine, diphenhydramine) where possible — they can mask deterioration. Take a single dose and reassess in 30 minutes.
When to walk in (we have prednisolone and a calm room)
Walk in to Manningham After-hours Emergency Care for any moderate reaction, particularly if:
- The reaction is spreading beyond the original site
- Lip, eye or face swelling has appeared
- You've had the same reaction before and it required medical care then
- You are uncertain and would rather be assessed
We can give a single dose of prednisolone (a fast-acting oral steroid), additional antihistamine, and monitor your observations for an hour. If the reaction escalates while you're with us, we will call an ambulance and transfer you to ED.
Follow-up after an allergic reaction
Anyone who's had a moderate or severe reaction should see their GP within a few days to:
- Identify the trigger, where possible
- Be referred to an allergy and immunology specialist
- Be prescribed an EpiPen if not already carrying one
- Develop an ASCIA Action Plan (Australasian Society of Clinical Immunology and Allergy)
Even mild first-time reactions are worth mentioning to your GP — knowing your triggers prevents recurrences.