Distinguishing DRESS from SJS: Clinical Features and Management
DRESS and SJS are distinct severe cutaneous adverse reactions that require different management approaches: DRESS presents with facial edema, eosinophilia, and prominent liver involvement developing 2-8 weeks after drug exposure, while SJS manifests with acute mucosal erosions, painful skin detachment, and epidermal necrolysis within days of drug initiation. 1, 2
Key Clinical Distinguishing Features
DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms)
Timing and Presentation:
- Onset 2-8 weeks after medication initiation 2
- Facial edema and extremity swelling are characteristic features 3
- Palmar and plantar involvement common 3
- Prodromal symptoms include itching, fever, and malaise 1
Laboratory and Organ Involvement:
- Eosinophilia is a defining feature 1, 4
- Liver involvement is the most common systemic manifestation 1
- Multiple organ systems affected (gastrointestinal tract, kidneys, lungs) 5
Skin Findings:
- Interface dermatitis with lichenoid pattern 2
- Periadnexal interface dermatitis 2
- Pigment incontinence 2
- Neutrophil dominance over eosinophils on histopathology 2
SJS (Stevens-Johnson Syndrome)
Timing and Presentation:
- Prodrome of fever, malaise, and upper respiratory symptoms precedes eruption by several days 6
- Cutaneous pain is a prominent early feature that should alert clinicians to incipient epidermal necrolysis 6
- Ocular inflammation may develop before skin signs appear 6
Mucosal and Skin Involvement:
- Extensive mucosal membrane involvement of eyes, mouth, nose, and genitalia is an early feature 6, 1
- Erosive and hemorrhagic mucositis 6
- Positive Nikolsky sign (minimal shearing forces cause epidermis to peel) 6
- Flaccid bullae with necrotic epidermis separating from dermis 6
- Subepidermal cleavage plane on biopsy 6
Extent of Involvement:
- SJS involves <10% body surface area with epidermal detachment 6, 7
- Can progress to SJS/TEN overlap (10-30% BSA) or TEN (>30% BSA) 6, 7
Common Causative Agents
Both conditions share similar culprit drugs:
- Antibiotics are the most common cause (DRESS 37%, SJS 40%) 1
- Anticonvulsants are the second most common (DRESS 27%, SJS 35%), particularly carbamazepine and lamotrigine 1, 3
- Allopurinol is a well-established inducer of both conditions 8, 9
- Sulfonamides, NSAIDs (especially oxicam-type), and dapsone 1, 8
Diagnostic Testing Considerations
Patch testing sensitivity differs significantly between conditions:
- DRESS has 64% positivity rate with patch testing 10
- SJS/TEN has only 24% positivity rate with patch testing 10
Critical timing for DRESS testing:
- Avoid patch testing or delayed intradermal testing until ≥6 months after acute reaction 10
- Patient must be off systemic corticosteroids for ≥1 month before testing 10
- Risk of DRESS relapse is 12%, and testing may trigger human herpesvirus reactivation 10
Management Approach
DRESS Management
Systemic corticosteroids are the cornerstone of treatment:
- DRESS shows rapid response to systemic corticosteroids 3
- Prolonged tapering required due to risk of relapse 10
- Monitor for viral reactivation during treatment 10
Immediate actions:
- Discontinue culprit drug immediately 11, 4
- Monitor liver function and other organ involvement closely 1
SJS Management
Immediate referral and specialized care:
- Refer immediately to multidisciplinary team with SJS/TEN experience 6
- Stop culprit drug immediately 6, 9
- Transfer to center with experience managing SJS/TEN 6
Specialized care requirements:
- BSA epidermal detachment >10% with comorbidity requires PICU or burns center admission 6
- BSA >30% with clinical deterioration may require surgical approach 6
- Mandatory ophthalmology involvement in multidisciplinary team 6
Immunomodulating therapy considerations:
- Cyclosporine and etanercept have been used, though response may be limited in overlap cases 3
- Supportive care remains fundamental 6, 7
Critical Pitfalls to Avoid
Do not rechallenge patients with negative patch testing for SCARs:
- Negative predictive value is imperfect for both conditions 10
- Never rechallenge with the specific culprit drug regardless of testing results 10
Recognize overlap syndromes:
- Cases with features of both DRESS and SJS have been reported, particularly with anticonvulsants 3
- Extensive mucosal involvement with subsequent facial edema and corticosteroid responsiveness suggests overlap 3
- When overlap is suspected, treatment may require combination approaches 3
Distinguish from mimickers: