Adrenaline and allergic reactions
A mild allergic reaction often causes no more symptoms than an itchy rash, this is not serious in itself, and may be treated with oral or topical antihistamines and cold showers / wet flannels. If difficulty in breathing or swallowing develops, and/or a sudden weakness regard these as serious symptoms requiring immediate treatment see below. Allergic diseases are on a spectrum with a mild rash at one end and life threatening anaphylaxis at the other.
Anaphylaxis
Anaphylaxis is caused by exposure to an antigen which triggers a cascading release of mediators (such as histamine). Causing the blood vessels to become leaky and inappropriately expanding (Dilation).
Anaphylaxis is potentially life threatening and requires prompt treatment to prevent deterioration and death. Its key features which differentiate it from an allergic reaction are;
If using any medication it is a wise precaution to prepare for Anaphylactic reactions.
Treatment
If using a vial of Adrenaline give 0.5mg intramuscularly (IM) or 0.3mg from an auto injector. The dose is repeated if necessary at 5-minute intervals.
If the patient show signs of poor perfusion or shock, intravenous fluids can be given in addition to the adrenaline.
An antihistamine e.g. Piriton can be given orally or by slow intravenous injection of 10mg. This should only be used once the acute phase of the anaphylaxis is over as the antihistamine may worsen any hypotension (low blood pressure)
An intravenous corticosteroid e.g. Hydrocortisone in a dose of 200 mg can also be given but takes around 6 hours to take effect.
Age Dose Volume of adrenaline (1 in 1000 (1 mg/ml)
Under 6 months 50 micrograms 0.05 ml
6 months–6 years 120 micrograms 0.12 ml
6–12 years 250 micrograms 0.25 ml
Adult and adolescent 500 micrograms 0.5 ml
The doses may be repeated several times if necessary at 5-minute intervals according to blood pressure, pulse and respiratory function.
Adrenaline acts quickly to constrict blood vessels, relax smooth muscles in the airways and improves breathing, it also stimulates the pulse.
Instructions for the administration of adrenaline via an auto injector
Grasp auto injector in dominant hand, with thumb closest to grey safety cap With the other hand, pull off grey safety cap.
Hold auto injector approximately 10cm away from thigh.
Black tip should point towards outer thigh
Jab firmly into outer thigh so that the auto injector is at a right angle to outer thigh, through clothing if necessary
Hold in place for 10 seconds.
Auto injector should be removed and handed to team taking over management of the patient if applicable.
Massage injection area for 10 seconds
Patient must be supervised because relapse can occur within a few hours and/or further management may be required
Do not
Anaphylaxis
Anaphylaxis is caused by exposure to an antigen which triggers a cascading release of mediators (such as histamine). Causing the blood vessels to become leaky and inappropriately expanding (Dilation).
Anaphylaxis is potentially life threatening and requires prompt treatment to prevent deterioration and death. Its key features which differentiate it from an allergic reaction are;
- Airway swelling
- Airway constriction
- Low blood pressure
- Altered level of consciousness
- A sudden onset
- Wheeze and/or Stridor (see chapter 1)
If using any medication it is a wise precaution to prepare for Anaphylactic reactions.
Treatment
- Maintain airway
- Maintain blood pressure (lay flat, raising the feet)
- Administer adrenaline
- Give an antihistamine
- Give Nebulised Salbutamol & Oxygen
If using a vial of Adrenaline give 0.5mg intramuscularly (IM) or 0.3mg from an auto injector. The dose is repeated if necessary at 5-minute intervals.
If the patient show signs of poor perfusion or shock, intravenous fluids can be given in addition to the adrenaline.
An antihistamine e.g. Piriton can be given orally or by slow intravenous injection of 10mg. This should only be used once the acute phase of the anaphylaxis is over as the antihistamine may worsen any hypotension (low blood pressure)
An intravenous corticosteroid e.g. Hydrocortisone in a dose of 200 mg can also be given but takes around 6 hours to take effect.
Age Dose Volume of adrenaline (1 in 1000 (1 mg/ml)
Under 6 months 50 micrograms 0.05 ml
6 months–6 years 120 micrograms 0.12 ml
6–12 years 250 micrograms 0.25 ml
Adult and adolescent 500 micrograms 0.5 ml
The doses may be repeated several times if necessary at 5-minute intervals according to blood pressure, pulse and respiratory function.
Adrenaline acts quickly to constrict blood vessels, relax smooth muscles in the airways and improves breathing, it also stimulates the pulse.
Instructions for the administration of adrenaline via an auto injector
Grasp auto injector in dominant hand, with thumb closest to grey safety cap With the other hand, pull off grey safety cap.
Hold auto injector approximately 10cm away from thigh.
Black tip should point towards outer thigh
Jab firmly into outer thigh so that the auto injector is at a right angle to outer thigh, through clothing if necessary
Hold in place for 10 seconds.
Auto injector should be removed and handed to team taking over management of the patient if applicable.
Massage injection area for 10 seconds
Patient must be supervised because relapse can occur within a few hours and/or further management may be required
Do not
- Use auto injector to practise emergency administration
- Remove grey safety cap until ready to use auto injector
- Place fingers over the black tip
- Attempt to inject into vein or buttocks
- Inject into extremities, as adrenaline causes blood vessels to constrict (Vasoconstriction).
