1. Acute onset of an illness (minutes to several hours) with simultaneous involvement of the skin, mucosal tissue, or both (e.g., generalized hives, pruritus or flushing, swollen lips-tongue-uvula) AND at least one of the following:

a. Respiratory compromise (e.g., dyspnea, wheeze-bronchospasm, stridor, reduced PEF, hypoxemia)

b. Reduced BP or associated symptoms of end-organ dysfunction (e.g., hypotonia [collapse], syncope, incontinence)

c. Severe gastrointestinal symptoms (e.g., severe crampy abdominal pain, repetitive vomiting), OR

2. Acute onset of hypotension or bronchospasm or laryngeal involvement after exposure to a known or highly probable allergen for that patient (minutes to several hours), even in the absence of typical skin involvement. OR

3. Danger signs for SCAR:

a. Tiny vesicles or crusts, grey‐violaceous or dusky color of lesions, painful or burning skin and/or mucosa in addition to fever and malaise, hemorrhagic erosions of mucous membranes and skin detachment (SJS/TEN)

b. Exanthema with pustules (AGEP)

c. Purpura (vasculitis)

d. Macules/papules together with non-cutaneous organ involvement; progression to more than 50% of the body surface area, deviating laboratory values (differential blood count, liver and kidney parameters) (DRESS).

e. Facial oedema, edematous and infiltrated skin inflammation. Acute fever of 38.5°C and higher. (AGEP/DRESS)

Note: if an MPE meets the symptom or CIOMS-criteria for a severe reaction, it should be considered as such.

Non-severe

1. Symptom(s)/sign(s) from 1 organ system present:

a. Cutaneous: urticaria, erythema-warmth, pruritus, tingling, itching of the lips.

b. Upper respiratory: nasal symptoms (e.g., sneezing, rhinorrhea, nasal pruritus, and/or nasal congestion), throat-clearing (itchy throat), cough not related to bronchospasm.

c. Conjunctival: erythema, pruritus, or tearing. OR

2. Maculopapular exanthema without organ involvement. OR

3. Other: nausea, metallic taste.