Distinguishing Features of DRESS Syndrome and SJS/TEN

Mucosal Involvement

The British Journal of Dermatology notes that mucosal involvement in SJS/TEN is severe, early, and a diagnostic hallmark, with involvement of the eyes, mouth, nose, and genitalia usually being an early feature, leading to erosive and hemorrhagic mucositis 1
Purulent keratoconjunctivitis with eyelid edema develops early in the acute phase of SJS/TEN, progressing to persistent ocular inflammation involving eyelid skin, as reported by the British Journal of Dermatology 3
Oral mucositis presents with mucosal erythema, blistering, and painful erosions that may require nasogastric tube feeding in SJS/TEN, according to the British Journal of Dermatology 1
Mucosal involvement can be so prominent in SJS/TEN that some cases present with predominantly mucous membrane involvement with little or no cutaneous lesions, as noted by the British Journal of Dermatology 5, 6
In contrast, mucosal involvement in DRESS is notably mild or absent, with the characteristic presentation being a morbilliform rash involving >30% body surface area without significant mucosal involvement, as described by the British Journal of Dermatology 2

The latency period differs significantly between DRESS and SJS/TEN, with DRESS typically occurring 2-6 weeks after drug exposure, while SJS/TEN symptoms usually begin 4-28 days after drug initiation, as reported by the British Journal of Dermatology 2
Immediate discontinuation of the culprit drug and transfer to a burn unit or ICU is mandatory in SJS/TEN, according to the British Journal of Dermatology 3, 4
In DRESS, systemic corticosteroids (IV methylprednisolone 1-2 mg/kg/day) are first-line therapy with a minimum 4-week taper required, as recommended by the British Journal of Dermatology 2
The American Academy of Dermatology notes that corticosteroids are not contraindicated in DRESS syndrome, unlike SJS/TEN where corticosteroid use remains controversial 2

DRESS syndrome demonstrates eosinophilia (>700/μL or >10% of WBCs) as a hallmark feature, prominent lymphadenopathy, and multi-organ involvement with hepatitis (ALT >2× ULN), nephritis, and potential cardiac involvement, as reported by the British Journal of Dermatology 2
SJS/TEN demonstrates epidermal detachment, with SJS <10% BSA, overlap 10-30% BSA, and TEN >30% BSA, according to the British Journal of Dermatology 1, 7
Full-thickness epidermal necrosis with confluent keratinocyte apoptosis is characteristic of SJS/TEN, as noted by the British Journal of Dermatology 7
Perivascular lymphocytic infiltration with dermal edema is seen in DRESS, with less extensive epidermal necrosis compared to SJS/TEN, as described by the British Journal of Dermatology 2