Stevens-Johnson syndrome and Toxic epidermal necrolysis spectrum

Question 1

Define SJS and TENS.

Answer 1

Stevens-Johnson syndrome (SJS) is a severe skin detachment with mucocutaneous complications. It is an immune reaction to foreign antigens.

SJS is a more severe form of erythema multiforme major and a less severe manifestation of toxic epidermal necrolysis (TEN).

Classification is dependent on the percentage of skin involvement: SJS has <10% total body surface area (TBSA) involvement; SJS/TEN overlap has 10% to 30% TBSA involvement; and TEN has >30% TBSA involvement.

Question 2

What is the aetiology of SJS and TENS?

Answer 2

1. Infection: SJS can be a sequela of a number of conditions, including:

• Upper respiratory tract infections
• Pharyngitis
• Otitis media
• Mycoplasma pneumoniae
• Herpes
• Epstein-Barr virus
• Cytomegaloviruses.

2. Vaccination: Smallpox vaccination can precipitate erythema multiforme or SJS.
3. Medicine:

• Anticonvulsants (e.g., carbamazepine, phenobarbital, phenytoin, valproic acid, lamotrigine)
• Antibiotics (e.g., sulfonamides, aminopenicillins, quinolones, cephalosporins)
• Antifungals
• Antiretrovirals (e.g., nevirapine, abacavir) and antivirals (e.g., telaprevir, aciclovir)
• Anthelmintics
• Analgesics (e.g., paracetamol)
• Non-steroidal anti-inflammatory drugs and selective COX-2 inhibitors
• Antimalarials
• Azathioprine
• Sulfasalazine
• Allopurinol
• Tranexamic acid
• Corticosteroids
• Psychotropic agents
• Chlormezanone
• Anticancer drugs (e.g., bendamustine, busulfan, chlorambucil)
• Retinoids

Question 3

What are risk factors for SJS and TENS?

Answer 3

Anticonvulsant medicines

Recent infection

Recent antibiotic use

Other medicines

Systemic lupus erythematosus

AIDS

Radiotherapy

Human leukocyte antigen and genetic predisposition

Smallpox vaccination

Question 4

Summarise the epidemiology of SJS and TENS.

Answer 4

Rare

Question 5

What are signs and symptoms of SJS and TENS?

Answer 5

Presence of risk factors

Rash

Mucosal involvement

Nikolsky’s sign - Epidermal layer easily sloughs off when pressure is applied to the affected area. More common in TEN than SJS.

Blisters

Question 6

What investigations should be performed for SJS and TENS?

Answer 6

Skin biopsy

Blood cultures

FBC

Glucose

Magnesium, Phosphate

U+Es

Bicarbonate

LFTs

Arterial blood gases and saturation of oxygen

Question 7

What is the management for SJS and TENS?

Answer 7

Urgent assessment and withdrawal of causative agent

Prophylactic anticoagulation

PPI

Topical antibiotics + emollients

Question 8

What are complications associated with SJS and TENS?

Answer 8

Dehydration

Abnormal skin pigmentation

Acute compartment syndrome

Infection

Occular complications

Nail plate loss

Acute liver failure

Acute renal failure

Hypothermia

Vaginal synechiae

Pulmonary complications

Ureteral perforation

Question 9

What is the prognosis of SJS and TENS?

Answer 9

Prognosis is best when:

• Patients are <50 years of age
• The total body surface area involved is low
• Patients are transferred to a burn centre
• Patients do not have sepsis
• Patients do not require antibiotics.

One study of paediatric patients with SJS or TEN admitted to a US hospital between 2000 and 2007 reported that 18% had a recurrence of SJS up to 7 years after the initial episode, and 47% had long-term sequelae. The mortality rate was lower than that reported in adults.