Allergy Symptoms Guide

Understanding the signs of allergic reactions and when to seek medical attention

Understanding Allergy Symptoms

Allergic reactions occur when your immune system overreacts to a substance (allergen) that's typically harmless to most people. These reactions can range from mild discomfort to life-threatening emergencies.

Symptoms can develop within minutes of exposure to an allergen or may take hours or days to appear, depending on the type of allergy. Understanding these symptoms can help you identify allergic reactions and seek appropriate treatment.

Important Note

This guide is for informational purposes only and should not replace professional medical advice. If you're experiencing severe symptoms, seek emergency medical attention immediately.

Common Allergy Symptoms by Body System

Skin Symptoms

Hives (urticaria): Raised, red, itchy welts of various sizes that appear and fade repeatedly
Angioedema: Swelling of deeper layers of skin, particularly around the eyes, lips, and face
Eczema flare-ups: Dry, itchy, red patches of skin that may become scaly, cracked, or weepy
Flushing: Redness and warmth in the skin, particularly on the face and neck
Itching: Can occur with or without visible skin changes

Respiratory Symptoms

Nasal congestion: Stuffy nose and sinus pressure
Runny nose: Clear, thin nasal discharge
Sneezing: Frequent, sometimes uncontrollable sneezing
Coughing: Persistent cough, often worse at night or early morning
Wheezing: High-pitched whistling sound when breathing, especially when exhaling
Shortness of breath: Difficulty breathing or feeling like you can't get enough air
Chest tightness: Feeling of pressure or constriction in the chest

Digestive Symptoms

Nausea and vomiting: Feeling sick to your stomach and potentially throwing up
Abdominal pain: Cramping or discomfort in the stomach area
Diarrhea: Loose, watery stools
Difficulty swallowing: Feeling like food is stuck in your throat or chest
Oral allergy syndrome: Itching or tingling in the mouth or throat after eating certain raw fruits or vegetables

Other Symptoms

Headache: Pain or pressure in the head, often accompanying sinus congestion
Fatigue: Feeling unusually tired or weak
Watery, itchy eyes: Redness, tearing, and irritation of the eyes
Brain fog: Difficulty concentrating or thinking clearly

Anaphylaxis: A Severe Allergic Reaction

Anaphylaxis is a severe, potentially life-threatening allergic reaction that can occur within seconds or minutes of exposure to an allergen. It requires immediate medical attention.

Emergency Warning

If you or someone around you is experiencing signs of anaphylaxis, use an epinephrine auto-injector (such as EpiPen®) if available and call emergency services (911 in the US) immediately. Do not wait to see if symptoms improve on their own.

Signs and Symptoms of Anaphylaxis

Constriction of airways: Severe difficulty breathing, wheezing, or high-pitched breathing sounds
Swelling of the throat: Making it difficult to breathe or swallow
Shock: Severe drop in blood pressure, rapid pulse, dizziness, lightheadedness, or loss of consciousness
Skin reactions: Widespread hives, redness, or swelling
Nausea, vomiting, or diarrhea: Severe digestive distress
Feeling of doom: A sense that something very bad is about to happen

Emergency Response to Anaphylaxis

Use epinephrine: If available, administer an epinephrine auto-injector as prescribed.
Call emergency services: Even if symptoms improve after using epinephrine, emergency medical care is still necessary.
Lie flat: Unless you're having trouble breathing or vomiting, lie flat with legs elevated to help blood flow.
Additional dose: If symptoms don't improve within 5-15 minutes, a second dose of epinephrine may be needed if available.

After an Anaphylactic Reaction

After experiencing anaphylaxis, it's crucial to follow up with an allergist to identify the trigger, develop an emergency action plan, and get prescriptions for epinephrine auto-injectors. Many people who have had one anaphylactic reaction are at risk for future reactions.

When to Seek Medical Attention

Seek Emergency Care Immediately If:

You experience any signs of anaphylaxis
You have difficulty breathing or shortness of breath
You experience swelling of the lips, tongue, or throat
You feel lightheaded, dizzy, or faint
You have a rapid or irregular heartbeat

Schedule an Appointment with an Allergist If:

You suspect you have an allergy but haven't been diagnosed
You've had mild to moderate allergic reactions in the past
Your allergy symptoms are not well-controlled with current treatments
You need guidance on managing allergies in specific situations (e.g., travel, school, work)
You want to explore treatment options like immunotherapy