SJS constitutes a dermatological emergency. Patients with documented "Mycoplasma" infections can be treated with oral macrolide or oral doxycycline.

Initially, treatment is similar to that for patients with thermal burns, and continued care can only be supportive (e.g. intravenous fluids and nasogastric or parenteral feeding) and symptomatic (e.g., analgesic mouth rinse for mouth ulcer). Dermatologists and surgeons tend to disagree about whether the skin should be debrided.

Beyond this kind of supportive care, no treatment for SJS is accepted. Treatment with corticosteroids is controversial. Early retrospective studies suggested corticosteroids increased hospital stays and complication rates. No randomized trials of corticosteroids were conducted for SJS, and it can be managed successfully without them.

Other agents have been used, including cyclophosphamide and cyclosporin, but none has exhibited much therapeutic success. Intravenous immunoglobulin treatment has shown some promise in reducing the length of the reaction and improving symptoms. Other common supportive measures include the use of topical pain anesthetics and antiseptics, maintaining a warm environment, and intravenous analgesics.

An ophthalmologist should be consulted immediately, as SJS frequently causes the formation of scar tissue inside the eyelids, leading to corneal vascularization, impaired vision, and a host of other ocular problems. Those with chronic ocular surface disease caused by SJS may find some improvement with PROSE treatment (prosthetic replacement of the ocular surface ecosystem treatment).

Swyer–James syndrome (SJS, also called Swyer–James–Macleod's syndrome) is a rare lung disorder found by English chest physician William Mathiseon Macleod, and (simultaneously) by physician Paul Robert Swyer and radiologist George James in the 1950s in Canada.

Swyer–James syndrome is a manifestation of postinfectious obliterative bronchiolitis. In SJS, the involved lung or portion of the lung does not grow normally and is slightly smaller than the opposite lung. The characteristic radiographic appearance is that of pulmonary hyperlucency, caused by overdistention of the alveoli in conjunction with diminished arterial flow. and has been linked to adenovirus type 21.

In appearance Swyer–James normally leaves shadowing in a CT scan in the upper lobar regions of one or (rarely) both lungs. Patients with the illness operate in much the same way as patients with mild bronchiectasis. As a result, the illness can go undiagnosed for some time. With current pharmaceutical developments, the prognosis is good for sufferers of the illness to lead normal and healthy lives.

The primary treatment of TEN is discontinuation of the causative factor(s), usually an offending drug, early referral and management in burn units or intensive care units, supportive management, and nutritional support.

Current literature does not convincingly support use of any adjuvant systemic therapy. Initial interest in Intravenous immunoglobulin (IVIG) came from research showing that IVIG could inhibit Fas-FasL mediated keratinocyte apoptosis in vitro. Unfortunately, research studies reveal conflicting support for use of IVIG in treatment of TEN. Ability to draw more generalized conclusions from research to date has been limited by lack of controlled trials, and inconsistency in study design in terms of disease severity, IVIG dose, and timing of IVIG administration.

Larger, high quality trials are needed to assess the actual benefit of IVIG in TEN.

Numerous other adjuvant therapies have been tried in TEN including, corticosteroids, cyclosporin, cyclophosphamide, plasmapheresis, pentoxifylline, N-acetylcysteine, ulinastatin, infliximab, and Granulocyte colony-stimulating factors (if TEN associated-leukopenia exists). There is mixed evidence for use of corticosteriods and scant evidence for the other therapies.

Moisture replacement therapies such as artificial tears may ease the symptoms of dry eyes. Some patients with more severe problems use goggles to increase local humidity or have punctal plugs inserted to help retain tears on the ocular surface for a longer time.

Additionally, cyclosporine (Restasis) is available by prescription to help treat chronic dry eye by suppressing the inflammation that disrupts tear secretion. Prescription drugs are also available that help to stimulate salivary flow, such as cevimeline (Evoxac) and pilocarpine. Salagen, a manufactured form of pilocarpine, can be used to help produce tears, as well as saliva in the mouth and intestines. It is derived from the jaborandi plant.

Nonsteroidal anti-inflammatory drugs (NSAIDs) may be used to treat musculoskeletal symptoms. For individuals with severe complications, corticosteroids or immunosuppressive drugs may be prescribed, and sometimes IVIG (intravenous immunoglobulin). Also, disease-modifying antirheumatic drugs (DMARDs) such as methotrexate may be helpful. Hydroxychloroquine (Plaquenil) is another option and is generally considered safer than methotrexate. However, these prescribed drugs have a range of side effects such as nausea, loss of appetite, dizziness, hair loss, stomach aches/cramps, headache, liver toxicity, and increased risk of infections. Also, people who take drugs to suppress the immune system are more likely to develop cancer later.

SJS (with less than 10% of body surface area involved) has a mortality rate of around 5%. The mortality for toxic epidermal necrolysis (TEN) is 30–40%. The risk for death can be estimated using the SCORTEN scale, which takes a number of prognostic indicators into account. It is helpful to calculate a SCORTEN within the first 3 days of hospitalization. Other outcomes include organ damage/failure, cornea scratching, and blindness.. Restrictive lung disease may develop in patients with SJS and TEN after initial acute pulmonary involvement. Patients with SJS or TEN caused by a drug have a better prognosis the earlier the causative drug is withdrawn.

Schwartz–Jampel syndrome (SJS) is a rare genetic disease caused by a mutation in the HSPG2 gene, which makes the protein perlecan, and causing osteochondrodysplasia associated with myotonia.

Most people with Schwartz–Jampel syndrome have a nearly normal life expectancy.

Relationships between the disease and perlecan deficiency have been studied.

The mortality for toxic epidermal necrolysis is 25-30%. People with SJS or TEN caused by a medications have a better prognosis the earlier the causative medication is withdrawn. Loss of the skin leaves patients vulnerable to infections from fungi and bacteria, and can result in sepsis, the leading cause of death in the disease. Death is caused either by infection or by respiratory distress which is either due to pneumonia or damage to the linings of the airway. Microscopic analysis of tissue (especially the degree of dermal mononuclear inflammation and the degree of inflammation in general) can play a role in determining the prognosis of individual cases.

The culprit can be both a prescription drug or an over-the-counter medication.

Examples of common drugs causing drug eruptions are antibiotics and other antimicrobial drugs, sulfa drugs, nonsteroidal anti-inflammatory drugs (NSAIDs), biopharmaceuticals, chemotherapy agents, anticonvulsants, and psychotropic drugs. Common examples include photodermatitis due to local NSAIDs (such as piroxicam) or due to antibiotics (such as minocycline), fixed drug eruption due to acetaminophen or NSAIDs (Ibuprofen), and the rash following ampicillin in cases of mononucleosis.

Certain drugs are less likely to cause drug eruptions (rates estimated to be ≤3 per 1000 patients exposed). These include: digoxin, aluminum hydroxide, multivitamins, acetaminophen, bisacodyl, aspirin, thiamine, prednisone, atropine, codeine, hydrochlorothiazide, morphine, insulin, warfarin, and spironolactone.

Erythema multiforme is frequently self-limiting and requires no treatment. The appropriateness of glucocorticoid therapy can be uncertain, because it is difficult to determine if the course will be a resolving one.

The treatment is (1) stop the offending drug (antibiotics), (2) symptomatic (fever), and (3) for complications (hepatitis).

The underlying mechanism can be immunological (such as in drug allergies) or non-immunological (for example, in photodermatitis or as a side effect of anticoagulants). A fixed drug eruption is the term for a drug eruption that occurs in the same skin area every time the person is exposed to the drug. Eruptions can occur frequently with a certain drug (for example, with phenytoin), or be very rare (for example, Sweet's syndrome following the administration of colony-stimulating factors).

AGEP is an acute febrile drug eruption characterized by numerous small, primarily non-follicular, sterile pustules, arising within large areas of red swollen skin.

The eruption follows a self-limiting course and will end before a week provided the causative agent (e.g. medication) is discarded. It is accompanied by fever, a high number of neutrophils and eosinophils in the blood, liver inflammation, and sometimes by facial swelling. The mortality rate is about 5% and the differential diagnosis includes Stevens–Johnson syndrome (SJS). Contrary to SJS, in AGEP, mucosa are not affected, which means that there are no blisters in the mouth or vagina.

Many suspected aetiologic factors have been reported to cause EM.

- Infections: Bacterial (including Bacillus Calmette-Guérin (BCG) vaccination, haemolytic "Streptococci", legionellosis, leprosy, "Neisseria meningitidis, Mycobacterium, "Pneumococcus, "Salmonella" species, "Staphylococcus" species, "Mycoplasma pneumoniae), "Chlamydial.

- Fungal (Coccidioides immitis)

- Parasitic ("Trichomonas" species, "Toxoplasma gondii), "

- Viral (especially Herpes simplex)

- Drug reactions, most commonly to: antibiotics (including, sulphonamides, penicillin), anticonvulsants (phenytoin, barbiturates), aspirin, antituberculoids, and allopurinol and many others.

- Physical factors: radiotherapy, cold, sunlight

- Others: collagen diseases, vasculitides, non-Hodgkin lymphoma, leukaemia, multiple myeloma, myeloid metaplasia, polycythemia

EM minor is regarded as being triggered by HSV in almost all cases. A herpetic aetiology also accounts for 55% of cases of EM major. Among the other infections, "Mycoplasma" infection appears to be a common cause.

Herpes simplex virus suppression and even prophylaxis (with acyclovir) has been shown to prevent recurrent erythema multiforme eruption.

Erythema multiforme major (also known as "erythema multiforme majus") is a form of rash with skin loss or epidermal detachment.

The term "erythema multiforme majus" is sometimes used to imply a bullous (blistering) presentation.

According to some sources, there are two conditions included on a spectrum of this same disease process:

- Stevens–Johnson syndrome (SJS)

- Toxic epidermal necrolysis (TEN) which described by Alan Lyell and previously called Lyell syndrome[5].

In this view, EM major, SJS and TEN are considered a single condition, distinguished by degree of epidermal detachment.

However, a consensus classification separates erythema multiforme minor, erythema multiforme major, and SJS/TEN as three separate entities.