Clinical Dermatology

Diagnostic Hallmarks

1. Distribution: trunk, palms, soles, lips, and other mucous membranes
2. Tense blisters arising from the center of an erythematous base
3. Presence of some target-type lesions

Clinical Presentation

Most patients with erythema multiforme do not develop bullous lesions . When blisters do occur, they are present from the onset of the illness and usually are a harbinger of a rather severe course. Bullae can occur anywhere on the body but are particularly likely to be found on the hands and feet. Unlike those that occur in pemphigus and pemphigoid, the bullae of erythema multifonne always arise from an erythematous base. Generally, the blisters form from the center (”bull’s-eye”) of a ringed or target-type lesion, but occasionally the bullae arise more eccentrically from a nonringed, erythematous plaque. Individual lesions range in size from 1.5 to 4 cm in diameter. The amount of itching present is highly variable, ranging from none at all to an intensity that interferes with sleep. Mucosal surfaces of the mouth, eyes, and genitalia are usually involved with widespread, painful erosions. These mucosal lesions may result in photophobia, urinary retention, and decreased intake of food and water.

The diagnosis of bullous erythema multiforme is made on a clinical basis. Biopsy can be of help, but often the pathologist can only state that it is consistent (rather than pathognomonic) of erythema multiforme. There are no characteristic immunofluorescent findings.

Erythema Multifarme Bullosum Variants-Patients with erythema multiforme who develop bullolls cutaneous lesions and erosive mucosal lesions in association with fever, malaise, and toxicity are said to have the Stevens Johnson syndrome. An even more severe variant in which the bullous trunk lesions become confluent to form huge areas of peeling skin and extensive burn-like erosions is known as toxic epidermal necrolysis. In both of these conditions patients become extremely sick, and there is a mortality rate of approximately 5%. Renal disease and arthralgias may accompany the high fever and mucocutaneous lesions. Hair and nails may be shed, and rarely blindness develops. These two variants are particularly likely to occur as a result of hydantoin and sulfa-type drug reactions. Toxic epidermal necrolysis must be differentiated from staphylococcal scalded skin syndrome.

Course and Prognosis

Bullous erythema multiforme is a more severe disease than the nonbullous variety. However, in most instances the disease will run its course in 10-15 days and then subside spontaneously. Lesions, in general, heal without evidence of scaning. When oral mucous membranes are involved, patients may not be able to eat or drink; hospitalization may then be required for intravenous therapy. Recurrent episodes of erythema multiforme bullosum are possible, particularly in those instances where the disease is associated with recunent herpes simplex infections.

Pathogenesis

In most instances, no etiology can be identified. However, the same possibilities considered for the other vascular reactions (medication reactions, infections, collagen-vascular disease, dysproteinemia, and systemic malignancy) should be evaluated in cases of erythema multiforme bullosum. Circulating immune complexes may be present, but there is little evidence dlat their deposition is important in pathogenesis. The picture is much clearer for recunent erythema multiforme, since herpes simplex DNA can be found with great regularity in lesional skin biopsies.

Therapy

Most patients with erythema multiforme bullosum will require no specific therapy. Patients with mucous membrane involvement, Stevens-Johnson syndrome, and toxic epidermal necrolysis will usually require hospitalization for intravenous fluids and evaluation of possible systemic involvement. Great controversy exists as to whether systemic steroids should be used. A majority of dermatologists are of the belief that the toxicity (mosdy secondary infection) much outweighs any potential benefit. On the other hand, some of us, including myself, believe that high-dose steroids generally in the form of pulsed intravenous methyl prednisolone (Solu-Medrol) are wananted if they can be administered within the first 72 hours of the disease.

In severe cases, intravenous control of fluid and electrolyte balance is warranted. If extensive erosive disease is present,treatment on a burn unit may be the most important aspect of therapy. In less severe cases, soaks may be useful for both their soothing and debriding effects. Swished analgesics such as elixir of Benadryl, Xylocaine Viscous, or Dyclone solution may be of help for control of the oral pain. Oral acyclovir therapy will prevent recunences in those cases known to be related to herpes simplex infection.

This entry was posted on Tuesday, September 4th, 2007 at 8:46 am and is filed under Vesiculobullous Diseases. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.