The Bottom Line

Stevens-Johnson Syndrome (SJS) is a rare but life-threatening drug reaction that causes the skin and mucous membranes to blister and peel off. It most commonly occurs as a reaction to medications — particularly antibiotics (sulfonamides), anticonvulsants (carbamazepine, lamotrigine, phenytoin), allopurinol, and NSAIDs. SJS is a medical emergency requiring immediate hospitalization. Early recognition of warning signs — fever, flu-like symptoms, painful skin, and mouth sores appearing 1-3 weeks after starting a new medication — can save your life.

What Is Stevens-Johnson Syndrome (SJS)?

Stevens-Johnson Syndrome is a severe, potentially fatal hypersensitivity reaction that causes widespread death of skin cells (epidermal necrosis), leading to blistering and detachment of the skin surface. SJS is defined by skin detachment affecting less than 10% of body surface area. When skin detachment exceeds 30%, it is classified as toxic epidermal necrolysis (TEN) — the most severe form on the same disease spectrum. Overlap (10-30% detachment) is called SJS-TEN overlap.

SJS is almost always caused by medications, typically appearing 1-3 weeks after starting the offending drug. It affects 1-6 people per million per year. Despite being rare, it is one of the most feared drug reactions due to its severity — mortality rates range from 1-5% for SJS to 25-35% for TEN.

Signs and Symptoms — Recognizing SJS Early

Prodromal symptoms (first 1-3 days — ACT NOW):

  • Fever (often 38-40°C / 100.4-104°F)
  • Flu-like symptoms: malaise, body aches, headache, sore throat
  • Painful skin — skin feels tender or burning before any visible changes appear
  • Painful mouth sores, difficulty swallowing
  • Eye redness, burning, or tearing

Skin involvement (days 2-5):

  • Dark red or purplish flat spots (macules) appearing on the trunk and face, spreading outward
  • Target-like lesions (some with dusky or necrotic centers) — atypical targets that look different from typical erythema multiforme
  • Skin becomes painful to touch — a key early sign
  • Nikolsky sign: Gentle lateral pressure on apparently normal skin causes it to shear off — a hallmark of SJS/TEN
  • Blisters and sheets of skin begin to separate and peel off, resembling a severe burn

Mucous membrane involvement (present in >90% of cases):

  • Painful oral erosions — lips, buccal mucosa, tongue (making eating nearly impossible)
  • Ocular involvement — conjunctivitis, corneal erosions (can cause permanent vision damage)
  • Genital mucosa — painful erosions
  • Respiratory mucosa — can cause breathing difficulties

What Causes Stevens-Johnson Syndrome?

Medications (cause >80% of cases): The highest-risk drugs are:

  • Antibiotics: Sulfonamides (trimethoprim-sulfamethoxazole/Bactrim), aminopenicillins, cephalosporins, fluoroquinolones
  • Anticonvulsants: Carbamazepine (Tegretol), lamotrigine (Lamictal), phenytoin (Dilantin), phenobarbital
  • Allopurinol: Used for gout — a well-documented SJS trigger
  • NSAIDs: Particularly piroxicam and other oxicam NSAIDs
  • Nevirapine: An HIV medication

Genetic risk factors: Specific HLA gene variants dramatically increase SJS risk with certain drugs. HLA-B*5801 increases allopurinol SJS risk 80-100 fold (most relevant in Southeast Asian and African American populations). HLA-B*1502 increases carbamazepine SJS risk in Southeast Asian populations. Genetic testing before starting these medications can prevent SJS.

Other triggers (rare): Infections (Mycoplasma pneumoniae — especially in children), vaccinations (very rare), and sometimes no identifiable cause.

Treatment — SJS Is a Medical Emergency

Immediate actions:

  1. STOP the suspected medication immediately — this is the single most important intervention. Earlier drug withdrawal is associated with significantly better survival.
  2. Call 911 or go to the emergency department — SJS requires hospital admission, often to a burn unit or ICU.

Hospital management:

  • Supportive care (most critical): Wound care similar to burn management, fluid replacement (significant fluid loss through damaged skin), temperature regulation, nutritional support, and pain management.
  • Eye care: Urgent ophthalmology consultation — daily eye examination, lubricating drops, and membrane removal to prevent corneal scarring and permanent vision loss.
  • Specific therapies (variable evidence): Cyclosporine (emerging evidence supports early use), IVIG (intravenous immunoglobulin), and systemic corticosteroids (debated — some centers use them early, others avoid them).
  • Avoid unnecessary medications to prevent additional drug reactions during this vulnerable period.

Recovery: Skin regrows over 2-4 weeks. Full recovery takes weeks to months. Long-term complications may include skin pigmentation changes, nail abnormalities, dry eyes and vision problems (in up to 50% of survivors), scarring of mucous membranes, and psychological impact (PTSD, anxiety, depression are common).

When to See a Dermatologist

SJS is diagnosed and managed in an emergency/hospital setting, not an outpatient dermatology office. However, if you develop any combination of fever, painful skin, mouth sores, and eye redness within 1-3 weeks of starting a new medication, seek EMERGENCY medical care immediately — do not wait for a dermatology appointment. After recovery, follow up with a dermatologist for long-term skin care, a drug allergy assessment to identify the causative drug, and documentation in your medical record to prevent re-exposure.

Frequently Asked Questions

How quickly does SJS develop after starting a medication?

SJS typically develops 1-3 weeks (7-21 days) after starting the causative medication, though it can occasionally appear up to 8 weeks later. The prodromal phase (fever, malaise, painful skin) precedes visible skin involvement by 1-3 days. Rapid recognition during this prodromal phase — especially the combination of fever and painful skin after recently starting a new drug — is critical for early intervention.

Can I ever take the medication that caused my SJS again?

NEVER. Re-exposure to the causative drug carries an extremely high risk of recurrence, often more severe than the first episode. The drug must be permanently avoided, and this must be documented prominently in your medical record, allergy bracelet, and pharmacy records. Chemically related drugs (e.g., other sulfonamides, other anticonvulsants in the aromatic class) may also need to be avoided — discuss this with your allergist or dermatologist.

Can genetic testing prevent SJS?

For certain high-risk drug-gene combinations, yes. The FDA recommends HLA-B*5801 testing before starting allopurinol (especially in at-risk populations) and HLA-B*1502 testing before starting carbamazepine in patients of Southeast Asian ancestry. If the high-risk allele is present, an alternative drug is used. Ask your doctor about genetic testing if you're prescribed allopurinol or carbamazepine.

What is the difference between SJS and TEN?

SJS and TEN are on the same disease spectrum, differing only in the amount of skin detachment: SJS affects less than 10% of body surface area, SJS-TEN overlap affects 10-30%, and TEN affects more than 30%. TEN is the most severe form with the highest mortality (25-35%). The disease mechanism, triggers, and initial presentation are identical — the severity of skin detachment determines the classification and prognosis.

References

  1. Harr T, French LE. Toxic epidermal necrolysis and Stevens-Johnson syndrome. Orphanet J Rare Dis. 2010;5:39.
  2. Mockenhaupt M. The current understanding of Stevens-Johnson syndrome and toxic epidermal necrolysis. Expert Rev Clin Immunol. 2011;7(6):803-815.
  3. Chung WH, Hung SI, Hong HS, et al. Medical genetics: a marker for Stevens-Johnson syndrome. Nature. 2004;428(6982):486.
  4. Schwartz RA, McDonough PH, Lee BW. Toxic epidermal necrolysis. J Am Acad Dermatol. 2013;69(2):173.e1-173.e13.

Trusted Resources

  • SJS/TEN Foundation. sjsten.org
  • National Organization for Rare Disorders. "Stevens-Johnson Syndrome." rarediseases.org
  • American Academy of Dermatology Association. "Drug Reactions." aad.org

SJS is a medical emergency. If you develop fever, painful skin, and mouth sores after starting a new medication, stop the drug and seek emergency care immediately.