DRESS vs SJS
How to tell DRESS and SJS apart when a board question makes them look alike.
Step 2 CK pairs are in open beta while clinical review finishes. Spot an issue? Tell us.
Mucosal erosions with epidermal detachment identify SJS rather than DRESS.
Side by side
Delayed drug eruption with fever, diffuse morbilliform rash, facial edema, eosinophilia, and internal organ involvement such as hepatitis.
Acute painful targetoid or purpuric lesions with mucosal erosions and epidermal detachment after high-risk medication exposure.
Drug-specific T-cell activation drives systemic hypersensitivity with eosinophilic inflammation of skin and organs.
Cytotoxic immune injury causes widespread keratinocyte apoptosis leading to mucocutaneous necrosis and skin detachment.
Absolute eosinophil count is often above 700 cells/uL, ALT or AST can exceed 100 U/L, creatinine may rise, and onset typically occurs 2 to 8 weeks after the culprit drug.
Skin biopsy shows full-thickness epidermal necrosis, epidermal detachment is less than 10% body surface area in SJS, and mucosal involvement is present in at least one site such as oral, ocular, or genital mucosa.
The trap
Both reactions can begin with fever and rash, so DRESS is often mistaken for SJS. The resolving clue is phenotype plus timing: DRESS usually appears weeks later with eosinophilia and organ injury, while SJS has early severe mucosal pain and epidermal sloughing that requires burn-unit style supportive care.
The repair move
Next best step: stop the offending drug immediately, admit for high-acuity supportive care with fluid and electrolyte replacement, wound care, and ophthalmology consultation. For DRESS phenotype with eosinophilia and organ injury, begin systemic corticosteroid such as prednisone 0.5 to 1 mg/kg/day and monitor liver and kidney function serially.
Try a free question
CoreA 30-year-old man started allopurinol 10 days ago and now has fever, painful oral erosions, conjunctivitis, and dusky skin lesions with epidermal peeling over 6% body surface area. BP 104/62 mm Hg, HR 118/min, temp 38.8 C. What is the next best step in management?
Show answer and explanation
Answer: B. Stop allopurinol and admit for supportive care with multidisciplinary monitoring. This is SJS pattern, so immediate drug withdrawal and inpatient supportive management are time-critical.
Why the other choices are tempting
- A. Wrong. Continuing the culprit drug worsens immune-mediated epidermal injury.
- C. Wrong. Antihistamines alone are inadequate for SJS.
- D. Wrong. The morphology and mucosal involvement argue against simple cellulitis.
- E. Wrong. Do not delay lifesaving supportive care for confirmatory pathology.
Flashcards
Tap a card to flip it.
Which skin and mucosal finding rapidly favors SJS over DRESS?
Painful mucosal erosions with epidermal detachment and positive Nikolsky sign favors SJS.
What lab pattern strongly supports DRESS in a febrile drug eruption?
Eosinophilia with elevated transaminases or creatinine several weeks after starting a culprit drug supports DRESS.
Quick answers
What is the fastest way to tell DRESS from SJS?
Mucosal erosions with epidermal detachment identify SJS rather than DRESS.
What is the key clue for DRESS?
Delayed drug eruption with fever, diffuse morbilliform rash, facial edema, eosinophilia, and internal organ involvement such as hepatitis.
What is the key clue for SJS?
Acute painful targetoid or purpuric lesions with mucosal erosions and epidermal detachment after high-risk medication exposure.
What is the common trap with DRESS vs SJS?
Both reactions can begin with fever and rash, so DRESS is often mistaken for SJS. The resolving clue is phenotype plus timing: DRESS usually appears weeks later with eosinophilia and organ injury, while SJS has early severe mucosal pain and epidermal sloughing that requires burn-unit style supportive care.