| Syndrome | Rash morphology | Localization | Timing | Internal organ involvement | Systemic signs | Laboratory findings |
| DHS/DRESS | Maculopapular exanthem Erythroderma Facial edema | Generalized Mucosal involvement infrequent | >14 days | Lymphadenopathy Hepatitis Pneumonitis Nephritis | Fever Malaise Fatigue | Eosinophilia, atypical lymphocytes Abnormal liver, renal function tests |
| AGEP | Widespread erythema Erythroderma Pustules (small, numerous) | Generalized, rarely flexural Mucosal involvement rare | <3 days | Possible but rare | High fever (>38°C/100.4°F) | Leukocytosis with neutrophilia (>7000/mm3) |
| SJS/TEN | Dusky red, coalescent macular exanthem Atypical target lesions Bullous lesions Epidermal necrosis (<10% in SJS, 10 to 30% in SJS/TEN, >30% in TEN) Nikolsky sign (ready removal of the epidermis with slight tangential pressure) | Disseminated Mucosal involvement nearly in all cases (stomatitis, conjunctivitis) | 4 to 21 days | Pneumonitis | Fever Malaise Fatigue Sore throat Dysphagia, photophobia | Lymphopenia Epidermal necrosis on skin biopsy with full thickness loss of epidermis |
