Stevens–Johnson syndrome

Disease Description (Causes and Symptoms)

• Definition summary: Stevens–Johnson syndrome (SJS) is an acute systemic epidermal–mucosal necrotic disease and a severe drug- or infection-related immune-mediated condition characterized by skin erythema and blisters, extensive epidermal detachment, and involvement of multiple mucous membranes. SJS and toxic epidermal necrolysis (TEN) are part of the same continuum and are distinguished according to the area of skin detachment (SJS <10% BSA, SJS/TEN overlap 10–30%, TEN >30%).
• Main causes: Most cases are caused by drugs (>50% of all SJS cases, 80–95% of TEN cases). Common triggering drugs include anticonvulsants (such as carbamazepine), sulfonamide antibiotics, some other antibiotics, NSAIDs (especially oxicam derivatives), antigout agents (allopurinol), and some anticancer drugs. Less commonly, infections (e.g., Mycoplasma pneumoniae and viruses), vaccinations, and graft-versus-host disease may be causes; approximately 5% of cases are idiopathic.
• Pathophysiology: A cell-mediated immune response to a drug or antigen causes massive necrosis of epidermal cells (keratinocytes) in the skin and mucous membranes → epidermal separation and mucosal ulceration. The risk of systemic inflammatory response and secondary infection increases.
• Main symptoms: After fever and general malaise, erythematous macules or targetoid lesions develop → blisters and epidermal detachment (Nikolsky sign may be positive). Involvement of the oral cavity and lips, conjunctiva, and genital/anal mucosa (mucosal lesions in most patients). Ocular complications such as conjunctivitis, symblepharon, and dry eye are common. Visceral involvement may cause difficulty breathing, difficulty swallowing, difficulty urinating, and malnutrition.
• Clinical indicators: Maximum deterioration occurs within several days of onset (e.g., 4–5 days); severity and prognosis differ according to the extent of lesions. Mortality varies from approximately 1% for SJS to 5–50% for TEN and is influenced by age, lesion extent, and comorbidities.

Treatment Methods (Standard Treatment, Medications, Procedures, Lifestyle Management, and Precautions)

• Immediate measures
  • Immediately discontinue the suspected causative drug (most important).
  • Immediate hospitalization according to severity (severe patients should be treated in a burn unit or intensive care unit).
• Supportive care (the core of treatment)
  • Correction of fluid and electrolyte abnormalities, pain control, nutrition (consider enteral feeding), and supportive measures (oxygen and airway management).
  • Skin care is similar to that for burn patients: sterile dressings, removal of necrotic tissue, and prevention of secondary infection.
  • Monitor for infection; use antibiotics only when there is a confirmed infection or physical signs of infection.
• Pharmacological and special treatments
  • Systemic corticosteroids: Short-term, high-dose use is performed in some patients, but the benefits and risks (such as increased infection risk) are controversial and should therefore be considered cautiously.
  • Intravenous immunoglobulin (IVIG): Used in some cases (evidence of efficacy is mixed).
  • Immunosuppressants (e.g., cyclosporine): May be considered because recent studies have reported possible improvement in survival rates.
  • Plasmapheresis and hemofiltration: Attempted in some severe cases.
  • TNF-α inhibitors (e.g., infliximab) and similar treatments are supported only by case reports.
• Ophthalmologic treatment (ophthalmology consultation is recommended from the early stage)
  • Artificial tears and lubricants, topical antibiotics, topical corticosteroids (at the discretion of an ophthalmologist), and, in cases of severe conjunctival damage, consideration of surgical treatment such as amniotic membrane transplantation.
• Prevention, education, and prevention of recurrence
  • Never readminister the suspected causative drug (it is recommended to record this in medical records and on an emergency card).
  • In populations known to have genetic susceptibility associated with specific drugs (HLA associations: e.g., allopurinol–HLA-B5801, carbamazepine–HLA-B1502), testing should be considered.
• Precautions and risk of complications
  • Major complications: Sepsis, multiple organ failure, permanent cutaneous and ophthalmologic sequelae (visual impairment and corneal scarring), scarring and hyperpigmentation, hair loss, and permanent mucosal damage.
  • Self-care: Do not take the suspected drug again; visit a hospital immediately if signs of infection occur (fever or purulent discharge); seek emergency ophthalmologic care if eye symptoms worsen.
  • Pregnant people, children, and older adults may have a poorer prognosis and require prompt treatment.

Checklist Before an Outpatient Visit (Including Example Questions)

• Items and information to prepare
  • A list of all medications currently being taken (including prescription drugs, over-the-counter medicines, herbal medicines, and health functional foods) — indicate when each medication was started (especially whether it was started within the past 4 weeks).
  • Any history of drug allergies or drug-induced rashes (when they occurred and which drug was involved).
  • The time of onset and progression of symptoms (submit photographs if available).
  • Current symptoms (fever, pain, difficulty breathing, difficulty swallowing, changes in vision, urinary abnormalities, etc.) and their severity.
  • Underlying conditions (kidney or liver disease, autoimmune disease, etc.), pregnancy status, and immunosuppressed status.
  • Recent infections (such as respiratory infections) or vaccination history.
  • Previous test results (blood tests, biopsy, HLA testing, etc.) and hospitalization records, if any.
• Items to check in advance at the outpatient visit
  • The relationship between the timing of medication use and symptom onset (confirm whether medication was started within the past 4 weeks).
  • Bringing photographs showing the progression of the lesions is recommended.
• Example questions (questions the patient can prepare in advance)
  • "Are any of the medications I am taking likely to cause SJS?"
  • "If these symptoms worsen, when should I go to the emergency room?"

Examples of General Questions to Ask the Doctor

• "Can we identify the drug that caused this with certainty? How high is the risk of taking it again?"
• "What is the standard treatment recommended for my condition, and do I need to be hospitalized?"
• "Which treatment is appropriate among corticosteroids, IVIG, and cyclosporine? What are the side effects?"
• "What are the risks of complications, especially involving the eyes, respiratory system, and kidneys, and how will follow-up be managed?"
• "What preventive measures should I take after recovery, such as an allergy card or a drug allergy record?"

Examples of Disease-Specific Questions

• "Do you suspect that the [name of drug] I am taking caused this? Should I avoid it permanently in the future?"
• "If the ocular mucosa is involved, what is the long-term visual prognosis, and how can early ophthalmologic treatment improve it?"

(Note: The information above has been organized based on the provided clinical summary information. Diagnosis and treatment for individual patients depend on the judgment of the treating medical staff and the results of additional tests.)