Stevens-Johnson syndrome signs and symptoms include:

• Fever
• Unexplained widespread skin pain
• A red or purple skin rash that spreads
• Blisters on your skin and the mucous membranes of your mouth, nose, eyes and genitals
• Shedding of your skin within days after blisters form

If you have Stevens-Johnson syndrome, several days before the rash develops you may experience:

• Fever
• Sore mouth and throat
• Fatigue
• Cough
• Burning eyes

Stevens-Johnson syndrome is a rare and unpredictable reaction. Your doctor may not be able to identify its exact cause, but usually the condition is triggered by a medication or an infection. A reaction to medication may start while you're using it or up to two weeks after you've stopped using it.

Infectious causes

Infections that can cause Stevens-Johnson syndrome include:

• Herpes virus (herpes simplex or herpes zoster)
• Pneumonia
• HIV
• Hepatitis A

Factors that increase your risk of developing Stevens-Johnson syndrome include:

• An HIV infection. Among people with HIV, the incidence of Stevens-Johnson syndrome is about 100 times greater than among the general population.
• A weakened immune system. If you have a weakened immune system, you may have an increased risk of Stevens-Johnson syndrome. Your immune system can be affected by an organ transplant, HIV/AIDS and autoimmune diseases.
• A history of Stevens-Johnson syndrome. If you've had a medication-related form of this condition, you are at risk of a recurrence if you use that drug again.
• A family history of Stevens-Johnson syndrome. If an immediate family member has had Stevens-Johnson syndrome or a related condition called toxic epidermal necrolysis, you may be more susceptible to developing Stevens-Johnson syndrome too.
• The HLA-B*1502 gene. If you have a gene called HLA-B 1502, you have an increased risk of Stevens-Johnson syndrome, particularly if you take certain drugs for seizures, gout or mental illness. Families of Chinese, Southeast Asian or Indian descent are more likely to carry this gene.

Stevens-Johnson syndrome complications include:

• Secondary skin infection (cellulitis). Cellulitis can lead to life-threatening complications, including sepsis.
• Blood infection (sepsis). Sepsis occurs when bacteria from an infection enter your bloodstream and spread throughout your body. Sepsis is a rapidly progressing, life-threatening condition that can cause shock and organ failure.
• Eye problems. The rash caused by Stevens-Johnson syndrome can lead to inflammation in your eyes. In mild cases, this may cause irritation and dry eyes. In severe cases, it can lead to extensive tissue damage and scarring that results in visual impairment and, rarely, blindness.
• Lung involvement. The condition may lead to acute respiratory failure.
• Permanent skin damage. When your skin grows back following Stevens-Johnson syndrome, it may have abnormal bumps and coloring. And you may have scars. Lasting skin problems may cause your hair to fall out, and your fingernails and toenails may not grow normally.