Diagnosis & Treatment — First aid / lay people
General problems
Individuals with certain pre-existing conditions are at particular risk. Coronary heart disease in particular makes the victim of severe allergic reactions susceptible to complications, such as myocardial infarction and arrhythmias. Beta-blockers suppress counter-regulatory mechanisms in anaphylactic shock, thus exacerbating the clinical course and impeding the ability to control the shock with medication (see Therapy phase General practitioner / health post: Comments).
Individuals who have experienced a reaction to a Hymenoptera sting in the past should consult with an allergist to determine which preventive measures are most appropriate to avoid complications in the event of another sting.
Emergency treatment of allergic reactions by lay people
1. Treatment of single stings in non-allergic individuals (local pain, itching, circumscribed local swelling)
Local application of ice/cold packs.
2. Emergency treatment for stings in the oral cavity
Seek medical assistance immediately due to the risk of laryngeal oedema and suffocation. If available: administer emergency medications (see below), in particular adrenaline via a Medihaler, as soon as any signs of laryngeal oedema develop.
3. Emergency treatment of a Hymenoptera sting by a lay person where the victim is known to have an allergy with cutaneous reactions (extensive local reaction of >10 cm in diameter and >24 hours' duration, urticaria or angio-oedema)
To be taken immediately following the sting: antihistamine (e.g. terfenadine 120 mg or loratadine 20 mg or clemastine 2 mg or cetirizine 20 mg)
plus
a corticosteroid (e.g. prednisone 100 mg) (Müller et al. 1991).
4. Emergency treatment of a Hymenoptera sting by a lay person where the victim is known to have an allergy with cardiovascular and respiratory reactions
To be taken immediately following the sting: antihistamine (e.g. terfenadine 120 mg or loratadine 20 mg or clemastine 2 mg or cetirizine 20 mg)
plus
a corticosteroid (e.g. prednisone 100 mg). Prepare adrenaline for self-injection1 (or inhalation) (see Comments below). As soon as systemic signs occur: injection or inhalation of adrenaline
plus
seek medical assistance (Müller et al. 1991).
1 N.B.: for patients who have suffered very severe reactions in the past, injected adrenaline is the treatment of choice! (BNF 1995).
Commercially available injection systems for self-administration of adrenaline (note the reduced dose for children, e.g. Epipen Jr.); trade name/manufacturer/dose in mg/administration route:
- Epipen/Center Labs/0.3/s.c.
- Epipen Jr./Center Labs/0.15/s.c.
- Anagit/Hollister-Stier/0.3/s.c.
- Min-I-Jet 0.5/IMS/0.5/s.c.
- Anahelp/Stallergenes/0.25/s.c.
- Fastjekt/Allergopharm/0.3/i.m.
Commercially available Medihaler; trade name/manufacturer/dose in mg/administration route: Medihaler-Epi/3M Riker/0.15 mg per inhalation/10–20 inhalations.
Local treatment
Sting, including the surrounding reaction.
Disinfection.
The risk of infection with blood-sucking insects and certain ant species (Solenopsis) is high in comparison to that with wasps and bees (Müller 1988).
Average time between the sting and death
Death due to an allergic reaction: in most cases following a single sting within minutes to <1 h (Barnard 1973, Mosbech 1983, Somerville et al. 1975); death due to a toxic reaction (multiple stings): hours to days.