Pemphigus erythematosus

(pictured) Patients with pemphigus erythematosus typically present with superficially eroded lesions, or vesiculobullae, that may ooze and crust. The lesions are initially flaccid bullae that progress to crusted or scaly erosions with a red/pink base. Other forms of pemphigus present with oral blisters, which are often the first symptoms of the disease. Pemphigus erythematosus, however, does not produce oral ulcers, or any other mucosal lesions. Pemphigus erythematosus targets desmoglein 1, which is primarily found in the skin. Desmoglein 3 is present in higher numbers in the mucosa. Pemphigus vulgaris targets desmoglein 3 and therefore produces mouth ulcers. == Pathophysiology ==

between skin cells are the target of pemphigus antibodies. Pemphigus patients experience an autoimmune reaction that targets desmosomes, which are the structures that hold skin cells together. Desmosomes are made of many different proteins, including proteins in the cadherin family like desmocollins and desmogleins. Patients with pemphigus have antibodies targeting their desmoglein proteins, triggering the immune system to destroy them. There has been one report of a new case of pemphigus erythematosus following topical ingenol mebutate treatment. == Diagnosis ==

Like other forms of pemphigus, pemphigus erythematosus is diagnosed by physical symptoms, skin biopsies, and blood tests. • Punch biopsies are the primary type of skin biopsy performed to diagnose pemphigus erythematosus. Hematoxylin and Eosin staining is used to view the appearance of the lesion under the microscope; these biopsy samples are taken from inside the blister. • Direct immunofluorescence studies are used to view the presence of pemphigus antibodies deposited between the skin cells; these biopsies are performed on perilesional skin (the skin next to the blister). This is the most specific diagnostic test for pemphigus erythematosus. • Indirect immunofluorescence studies can also be used to view the presence of pemphigus antibodies, however, this test involves taking a sample of the patient's blood and testing it on animal tissue (eg. monkey esophagus) and does not require a biopsy. • Anti-desmoglein antibody serology may be used to find antibodies in the blood that are unique to pemphigus erythematosus. Patients with the disease will have a positive ELISA result for anti-desmoglein-1 antibody and a negative result for anti-desmoglein-3 antibodies. • Antinuclear antibody (ANA) serology can be used as a screening test for pemphigus erythematosus. This test is not specific to the disease, but high titers of ANA and SSA in a patient with facial blisters on sun-exposed skin is highly suggestive of pemphigus erythematosus. == Treatment ==

(Anti-CD20 antibody) has been used to treat pemphigus erythematosus. Immunosuppressant medication is the most common treatment for pemphigus erythematosus. It has been shown effective in treating cases of pemphigus vulgaris that did not respond to corticosteroids. Several recent case reports have shown its effectiveness in treating pemphigus erythematosus. Other anti-CD20 monoclonal antibodies such as ocrelizumab, veltuzumab, and ofatumumab have been suggested for the management of pemphigus. Immunoadsorption and plasmapheresis have also been shown to be useful treatments for pemphigus erythematosus. == See also ==