Pharmacology of Selected Therapeutic Agents in Oral Medicine
Pemphigus

Pemphigus comprises a group of potentially fatal autoimmune bullous diseases targeting the skin and mucous membranes. Five categories of pemphigus have been described: pemphigus vulgaris (PV), pemphigus foliaceous, paraneoplastic pemphigus (PNP), drug-induced pemphigus, and IgA pemphigus.¹³ However, only PV and PNP typically affect the oral cavity. Most cases are diagnosed in the fifth to sixth decade and there is no gender predilection.²⁸

Ashkenazi Jews and persons of Mediterranean descent are at higher risk of developing PV. Of relevance for the dentist is the fact that the first manifestation of PV is often an oral blister or ulcer. PV is an autoimmune condition in which autoantibodies targeting intraepithelial adhesion molecules (desmosomes) induce disruption of cell adhesion resulting in acantholysis. The target antigens in PV are the cadherin family antigens desmoglein 1 (DSG1) and desmoglein 3 (DSG3).

PV characteristically presents as painful superficial ulcerations affecting the oral mucosa and oropharynx (Figure 6). Gingival involvement often manifests as desquamative gingivitis. Intact oral blisters are rarely observed, due to their fragility and patients with PV characteristically demonstrate a positive Nikolsky sign. The presence of cutaneous lesions implies a worsening course and mandates prompt medical evaluation and therapy.

The average time in which oral PV progresses to involve cutaneous sites is estimated to be 4-6 months.²⁶ The diagnosis of PV is established by correlating the clinical findings with direct immunofluorescence (DIF) histological examination. Once diagnosed, the patients with PV should be referred to a dermatologist.

Therapeutic Strategies

It is now acknowledged that long-term topical glucocorticoid regimens, as described above for MMP, are insufficient to manage PV because of its progressive nature. The newly diagnosed patient with PV should be referred to a dermatologist for long-term combination immunopharmacotherapy, which may include rituximab, corticosteroids, azathioprine, cyclophosphamide, mycophenolate mofetil, intravenous immunoglobulin, and other immunomodulators.²⁶