What are the main red flags, symptoms, signs, investigations, and key points to document in progress notes for a patient with a suspected drug allergy, considering their medical history, comorbidities (e.g. asthma, cardiovascular disease), and potential for anaphylaxis?

Documentation of Drug Allergy: Critical Red Flags, Symptoms, Signs, and Investigations

When documenting a suspected drug allergy in progress notes, immediately record the temporal relationship between drug exposure and symptom onset, classify the reaction as severe versus non-severe using standardized criteria, and document specific symptoms across all organ systems to guide future treatment decisions and prevent potentially fatal re-exposure. 1

Red Flags Requiring Immediate Recognition and Documentation

Life-Threatening Severe Reactions (Document Immediately)

Anaphylaxis criteria - Document if the patient has acute onset (minutes to several hours) with skin/mucosal involvement (generalized hives, pruritus, flushing, swollen lips-tongue-uvula) AND any of the following: 1

• Respiratory compromise: dyspnea, wheeze-bronchospasm, stridor, reduced peak expiratory flow, hypoxemia
• Reduced blood pressure or end-organ dysfunction: hypotension, collapse, syncope, incontinence
• Severe gastrointestinal symptoms: severe crampy abdominal pain, repetitive vomiting

Anaphylaxis without typical skin involvement - Document if acute onset of hypotension, bronchospasm, or laryngeal involvement occurs after drug exposure, even without skin findings 1

Severe Cutaneous Adverse Reactions (SCARs) - Document these danger signs: 1

• Tiny vesicles or crusts with grey-violaceous or dusky colored lesions
• Painful or burning skin and/or mucosa with fever and malaise
• Hemorrhagic erosions of mucous membranes and skin detachment (Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis)
• Exanthema with pustules (Acute Generalized Exanthematous Pustulosis)
• Purpura suggesting vasculitis
• Macules/papules with non-cutaneous organ involvement, progression to >50% body surface area, abnormal differential blood count, liver and kidney parameters (Drug Reaction with Eosinophilia and Systemic Symptoms)
• Facial edema with oedematous, infiltrated skin inflammation and acute fever ≥38.5°C

Essential History Components to Document

Temporal Details (Critical for Classification)

Index date determination - Record the exact date when the first symptom or sign appeared (sore throat, rash, skin pain, sore eyes/mouth), not just when the rash was noticed 1

Timing of drug exposure - Document: 1

• Date of occurrence of the reaction
• All drugs taken over the previous 2 months, including over-the-counter and complementary/alternative therapies
• Date when each treatment was started
• Date of dose escalation when appropriate
• Date when drugs were stopped
• Any brand switches or medication errors

Onset pattern - Record whether symptoms appeared: 1

• Within 1 hour after first dose (suggests immediate-type IgE-mediated reaction, particularly if urticaria fulfills "1-1-1-1" criterion: appearance within 1 hour after first dose, regression within 1 day, occurrence within 1 year)
• After several hours to days (suggests delayed-type reaction)

Symptom Documentation by Organ System

Cutaneous symptoms (present in 90% of drug allergies) - Document: 1

• Urticaria and angioedema (85-90% of cases)
• Flushing (45-55% of cases)
• Pruritus without rash (2-5% of cases)
• Location, extent, and progression of rash

Respiratory symptoms (present in 40-60% of cases) - Document: 1

• Dyspnea, wheeze (45-50% of cases)
• Upper airway angioedema (50-60% of cases)
• Rhinitis (15-20% of cases)
• Cough, bronchial hypersecretion, hemoptysis

Cardiovascular symptoms (30-35% of cases) - Document: 1

• Dizziness, syncope, hypotension
• Palpitations, chest tightness

Gastrointestinal symptoms (25-30% of cases) - Document: 1

• Nausea, vomiting, diarrhea, cramping pain
• Abdominal distension

Mucosal involvement - Document involvement of: 1

• Eyes (conjunctival erythema, pruritus, tearing)
• Mouth (mucositis, blisters, erosions)
• Nose
• Genitalia

Neurological symptoms - Document: 1

• Headache (5-8% of cases)
• Seizure (1-2% of cases)

Patient-Specific Risk Factors to Document

Comorbidities increasing risk - Note presence of: 1

• Concurrent medications that may confound diagnosis
• History of recurrent HSV infections
• Chest infections
• Asthma (increases risk of severe anaphylaxis)
• Cardiovascular disease

Previous drug allergy history - Document: 1

• Details of previous reaction type
• Whether patient has used the same drug since the index reaction without problems (if yes, allergy label can be removed)
• Whether allergy label was based solely on family history or fear of allergy (if yes, can be removed)

Severity Classification for Progress Notes

Severe Reactions (Document as High Priority)

Record as SEVERE if any of the following are present: 1

• Anaphylaxis criteria met (as defined above)
• Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis danger signs
• Acute Generalized Exanthematous Pustulosis features
• Drug Reaction with Eosinophilia and Systemic Symptoms features
• Vasculitis (purpura)
• Maculopapular exanthema meeting CIOMS criteria for severe reaction

Non-Severe Reactions (Document but Lower Priority)

Record as NON-SEVERE if only the following are present: 1

• Symptoms from single organ system: cutaneous only (urticaria, erythema-warmth, pruritus, tingling/itching of lips), upper respiratory only (nasal symptoms, throat-clearing, cough not related to bronchospasm), or conjunctival only (erythema, pruritus, tearing)
• Maculopapular exanthema without organ involvement
• Nausea, metallic taste only

Investigations to Document

Immediate Laboratory Studies

During acute reaction - Document results of: 1

• Full blood count with differential (look for eosinophilia)
• Erythrocyte sedimentation rate
• C-reactive protein
• Urea and electrolytes
• Magnesium, phosphate, bicarbonate
• Glucose
• Liver function tests (look for hepatic involvement)
• Coagulation studies
• Serum tryptase (must be obtained at proper timing: within 1-2 hours of symptom onset for anaphylaxis confirmation) 1

Imaging - Document: 1

• Chest X-ray findings (to assess respiratory involvement)

Microbiological studies - Document: 1

• Swabs from lesional skin for bacteriology
• Mycoplasma serology

Tissue Diagnosis

Skin biopsy - Document if obtained: 1

• Biopsy from lesional skin adjacent to blister sent for routine histopathology
• Second biopsy from periblister lesional skin sent unfixed for direct immunofluorescence (to exclude immunobullous disorders)

Extent of Involvement Documentation

Body surface area assessment - Record: 1

• Percentage of body surface area with erythema (use Lund and Browder chart)
• Percentage of body surface area with epidermal detachment, including detachable epidermis (Nikolsky positive) and detached epidermis - this figure has prognostic value
• Document on body map showing location and extent

Photographic documentation - Obtain and document: 1

• Photographs showing type of lesion and extent of involvement

Delayed Allergy Testing (Document Plans For)

Referral criteria - Document need for specialist referral if any of the following occurred: 1

• Unexplained cardiac arrest during anesthesia
• Unexplained, unexpected hypotension (decrease of mean arterial pressure >30 mmHg) requiring active treatment
• Unexplained, unexpected bronchospasm, particularly if severe, causing significant oxygen desaturation and relatively resistant to treatment
• Widespread rash, flushing, or urticaria
• Angioedema

Skin testing plans - Document that patient should be referred for: 1

• Skin prick testing and intradermal testing (for immediate hypersensitivity reactions)
• Testing should occur after full clinical recovery and after antihistamine effects have worn off
• For beta-lactam allergies, specific concentrations for testing are standardized 1

Drug provocation testing - Document that: 1

• Drug provocation test may be needed if skin tests are negative
• Should only be performed in controlled setting with appropriate monitoring
• Oral provocation studies are not ethical in Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis due to risk of life-threatening reactions 1

Critical Documentation Elements for Future Care

Allergy Label Documentation

Minimum required information - Progress notes must include: 1

Patient details:

• Specific symptoms of the reaction
• Date of the reaction
• Concurrent medications at time of reaction
• Relevant comorbidities

Medication details:

• Exact drug name (generic and brand)
• Route of administration
• Timing of administration relative to symptom onset
• Dose administered

Treatment details:

• Setting where reaction occurred
• Time to resolution of symptoms
• Management provided
• Outcome of the reaction

Distinguishing True Allergy from Non-Allergic Reactions

Document as NOT true allergy if: 1

• Symptoms are not compatible with allergic reaction (gastrointestinal complaints only, palpitations, blurred vision, headache)
• No temporal association between drug exposure and symptom onset
• Patient has used the drug since the index reaction without problems
• Allergy label was based solely on family history or fear of allergy

Document as possible viral exanthema if: 1

• Maculopapular rash occurred during treatment for infection
• Timing and characteristics suggest concurrent viral illness rather than drug reaction

Common Pitfalls to Avoid in Documentation

Incomplete temporal documentation - Failure to record exact timing between drug administration and symptom onset prevents proper classification as immediate versus delayed reaction 1

Confusing extent of erythema with extent of detachment - For severe cutaneous reactions, the extent of epidermal detachment (not erythema) has prognostic value and must be documented separately 1

Missing cross-reactivity considerations - Document the drug class and chemical structure, as cross-reactivity occurs within same class or between drugs with similar R1 side chains (particularly relevant for beta-lactams) 1, 2

Failing to document negative findings - Explicitly document absence of severe features (no respiratory compromise, no hypotension, no mucosal involvement) to clarify reaction severity 1

Inadequate follow-up planning - Document specific plans for: 1

• MedicAlert bracelet recommendation with culprit drug name
• Communication to all treating physicians, especially general practitioner
• Warning about over-the-counter medications with unclear constituents
• Reporting to national pharmacovigilance authorities (Yellow Card Scheme in UK, similar systems elsewhere)
• Specialist follow-up appointments (ophthalmology if eye involvement, dermatology/allergy within weeks of discharge)

Premature skin testing - Document that skin testing sensitivity decreases over time; shorter interval between reaction and evaluation (<1 year) is associated with higher odds of positive testing 1