Indication for Self-Injectable Adrenaline (Epinephrine)

Self-injectable adrenaline devices (e.g., auto-injectors) are prescribed for the emergency, patient-administered treatment of anaphylaxis — a severe, rapidly progressive, life-threatening allergic reaction. They are given to patients who have a known risk of anaphylaxis, particularly when the triggering allergen (such as certain foods, insect stings, or drugs) cannot be reliably avoided, so that treatment is immediately available before emergency medical help arrives.

Analysis of Options

• Complete heart block: Incorrect. This is a cardiac conduction disorder treated with a pacemaker or, acutely, with drugs such as atropine or isoprenaline/transcutaneous pacing — not with self-injectable adrenaline. Adrenaline is not a standard or safe outpatient self-treatment for heart block.
• Cardiogenic shock: Incorrect. Cardiogenic shock is a hospital emergency managed with inotropes, mechanical circulatory support, and treatment of the underlying cause under close monitoring; it is not an indication for a patient-carried adrenaline auto-injector.
• Pheochromocytoma: Incorrect. This tumour itself secretes excess catecholamines (including adrenaline/noradrenaline), causing episodic hypertension. Giving additional adrenaline would dangerously worsen the condition, so it is contraindicated, not indicated.
• Anaphylaxis to allergens that are difficult to avoid: Correct. This is the classic indication — patients with known severe allergies (e.g., to insect venom, certain foods, or latex) that are hard to completely avoid in daily life are prescribed self-injectable adrenaline to use immediately at the onset of an anaphylactic reaction, buying time until emergency care is reached.

Therefore, the correct answer is anaphylaxis to allergens that are difficult to avoid, consistent with standard emergency medicine and allergy management guidelines.