MMP is a group of chronic, autoimmune diseases characterized by the formation of subepithelial blisters that typically involve mucous membranes. The annual incidence of MMP is estimated to be 1.3–2.0 per million, the typical age of onset is the sixth to eighth decade, and there is a female predilection (2:1).13
The etiopathogenesis of MMP entails the production of autoantibodies directed against a variety of proteins within the basement membrane zone (BMZ). Identified autoantibody targets include BP180, BP230, laminin 332, laminin 311, α6ß4 integrin, and type VII collagen.26 An antibody-induced complement-mediated process results in epithelial detachment and reactive migration of lymphocytes, eosinophils, neutrophils and mast cells to the BMZ.
MMP may present as mucosal blistering, but most often it affects the gingiva and appears as desquamative gingivitis (Figure 5).26 Extraoral involvelment is rare, but MMP may affect the conjunctiva, nasopharynx, larynx, esophagus and anogenital region. A positive Nikolsky sign is often noted. Nikolsky's sign is the application of frictional horizontal pressure to the mucosa and/or skin to induce a blister or slough.27
Figure 5. Mucous Membrane Pemphigoid 47-year-old Male.
The major long-term concern with MMP is the risk for scarring of the eyes, esophagus, larynx, and genitalia. The diagnosis of MMP is typically established by correlating the clinical findings with direct immunofluorescence (DIF) histological examination. Patients diagnosed with MMP warrant a medical evaluation to assess for potential extraoral involvement, especially ophthalmologic.26
There is no cure for MMP and therapeutic strategies are aimed to decrease inflammation, promote healing and alleviate symptoms. For intraoral lesions, the use of topical steroids such as fluocinonide, clobetasol, and betamethasone in gel presentations remain first line therapy. The use of a soft resilient splint as a medication delivery tray facilitates the administration of the medication in cases of gingival involvement.
When using topical steroids for a prolonged period of time to treat larger areas, it is important to monitor for side effects such as candidiasis.13 Patients not responding to topical steroids may respond to secondary-line agents such as topical calcineurin-inhibitors such as tacrolimus and pimecrolimus. Intra-lesional injections of triamcinolone acetonide (10mg/mL, injecting 0.1mg/cm3) may be helpful for recalcitrant, symptomatic lesions in conjunction with the topical therapy.
Patients with MMP not responding to topical or intra-lesional steroid injections should be referred to a dermatologist for long-term combination immunopharmacotherapy, which may include glucocorticoids, azathioprine, cyclosporine, methotrexate, TNF-α inhibitors, and other immunomodulators.26