EM is a mucocutaneous inflammatory disease that results in generalized mucosal tissue breakdown. This breakdown is caused by immune complexes that form and leak out of the connective tissue vessel walls; the result is leukocytic infiltration that includes neutrophils and macrophages. These white blood cells, in turn, release lytic enzymes and free radical species that cause breakdown of the epithelium and tissue necrosis.1
The clinical oral presentation consists of bullous formation, ulceration, and diffuse desquamation of mucosa. EM has been associated with certain drugs (eg, hypoglycemic sulfonylureas, sulfa antibiotics, carbamazepine(Drug information on carbamazepine), levofloxacin, antitubercular drugs, NSAIDs, barbiturates, phenylbutazone(Drug information on phenylbutazone)); with certain viruses (eg, herpes simplex virus [HSV], cytomegalovirus, Epstein Barr virus) and Mycoplasma pneumoniae; and even with seasonal influenza vaccine coupled with flucloxacillin(Drug information on flucloxacillin).2 In most cases, however, a definite underlying cause is not readily identified. Thus, the diagnosis is based on the history, clinical presentation, and absence of histology/pathology suggestive of other conditions.
Different forms of the condition have been defined:
• A mild form (EM minor) that involves oral ulceration and skin lesions of variable type, including bullous manifestations or lesions with a “bulls-eye or target” appearance
• An intermediate form (EM major)
• A severe form that can involve desquamative blisters of the skin, oral mucosa, genitalia, and conjunctiva (Stevens-Johnson syndrome or toxic epidermal necrolysis)
The incidence of EM in adults and children is not clear but at least one study calculated an overall risk of Stevens-Johnson syndrome in the general population of 0.93 per million.
Minor EM is self-limited but may last for 14 to 21 days. The moderate form may persist for months.
The histopathologic features associated with EM are nonspecific but involve inflammatory changes. The submucosa demonstrates a polymorphic infiltrate with lymphocytes, mast cell degranulation, and neutrophils.
The management of EM depends on disease severity. Minor EM requires only supportive care because the condition is typically self-limited. If an offending medication is identified, it must be avoided in the future so as not to induce more severe pathology. Self-care should include the maintenance of good oral hygiene if possible, a bland but balanced diet when the condition flares, and a diet rich in vitamins C and A. Oral antihistamines, analgesics, and topical corticosteroids can also be beneficial; the latter includes fluocinonide(Drug information on fluocinonide) ointment in orabase or clobetasol(Drug information on clobetasol).
In patients who experience EM after HSV infection that occurs 5 or more times a year, antiviral prophylaxis can reduce EM recurrences. The antiviral may have to be continued for a prolonged period if effective.
Prophylactic antibiotics are not recommended.
Occassionally, systemic prednisone delivered in a tapered schedule can be employed if lesions do not respond to topical measures.
Moderate EM may necessitate a higher starting dose with a longer taper period. Azathioprine(Drug information on azathioprine) (50 mg) may also be added to lower the dose of corticosteroid if it is needed for a prolonged period.3
With severe disease (which is life-threatening), management is complex and best delivered in the hospital. Prednisone(Drug information on prednisone) (60 mg total dose delivered every day) coupled with daily azathioprine (150 mg) or CellCept (3 g every day) may be prescribed. However, the use of a corticosteroid in this setting remains controversial because its use can confound the management of secondary infection when there is severe dermal sloughing. Both the physician and dentist should manage the dermal/medical/oral complications associated with prolonged EM involvement.4