T78.0 Anaphylactic reaction due to food

Name of the Condition

• Anaphylactic reaction due to food (ICD-10 Code: T78.0)

Summary

This code is used to document an anaphylactic reaction specifically triggered by food. Anaphylaxis is a severe, potentially life-threatening allergic reaction that requires immediate medical attention. The code applies when the reaction is directly linked to food exposure and meets clinical criteria for anaphylaxis.

Causes

Anaphylactic reactions due to food occur when the immune system overreacts to specific proteins in food. Common triggers include peanuts, tree nuts, shellfish, fish, milk, eggs, soy, and wheat. The reaction is mediated by immunoglobulin E (IgE) antibodies, which release histamine and other chemicals, leading to rapid onset of symptoms.

Risk Factors

• Previous history of food allergies or anaphylaxis
• Family history of allergic conditions
• Asthma or other atopic diseases
• Exposure to known food allergens
• Delayed administration of epinephrine during prior reactions

Symptoms

• Rapid onset of hives, itching, or swelling (especially of the lips, tongue, or throat)
• Difficulty breathing, wheezing, or stridor
• Drop in blood pressure (hypotension) or dizziness
• Nausea, vomiting, or abdominal cramps
• Loss of consciousness or confusion

Diagnosis

Diagnosis is based on clinical presentation and patient history. Key criteria include acute onset of symptoms affecting multiple organ systems (skin, respiratory, gastrointestinal, or cardiovascular) after food exposure. Laboratory tests (e.g., serum tryptase) may support the diagnosis but are not always required for coding.

Treatment Options

• Immediate administration of epinephrine (first-line treatment)
• Antihistamines and corticosteroids for symptom relief
• Oxygen therapy or airway support if needed
• Intravenous fluids for hypotension
• Observation in a medical facility for at least 4–6 hours post-reaction

Prognosis and Follow-Up

With prompt treatment, most patients recover fully. Long-term management includes strict avoidance of the trigger food, carrying an epinephrine auto-injector, and follow-up with an allergist. Patients should also have an emergency action plan and wear medical identification.

Complications

• Respiratory failure or arrest
• Cardiovascular collapse
• Asphyxiation from airway swelling
• Delayed biphasic reactions (recurrence of symptoms hours later)
• Anxiety or post-traumatic stress related to the event

Lifestyle & Prevention

• Identify and avoid all known food allergens
• Read food labels carefully and ask about ingredients when dining out
• Carry an epinephrine auto-injector at all times
• Educate family, friends, and caregivers on emergency response
• Consider allergen immunotherapy (e.g., oral immunotherapy) for high-risk individuals

When to Seek Professional Help

Seek immediate medical attention if symptoms of anaphylaxis occur, including difficulty breathing, swelling of the throat, dizziness, or loss of consciousness. Do not wait for symptoms to worsen. Call emergency services or go to the nearest emergency department.

Tips for Medical Coders

Document the specific food trigger when known, as this may support the diagnosis. Ensure the clinical notes describe the severity (e.g., respiratory or cardiovascular involvement) to justify the code. For subsequent encounters, specify if the reaction was confirmed or suspected, and note any follow-up care (e.g., allergist referral). Avoid using this code for non-food-related anaphylaxis.