Dermatomyositis followed by pemphigus foliaceus: a case report and possible mechanism

Dermatomyositis (DM) and Pemphigus foliaceus (PF) are two autoimmune diseases that are rarely reported in the same patient. DM is an idiopathic inflammatory myopathy with characteristic skin manifestations. Muscle involvement manifests as proximal weakness. Muscle tenderness may occur but is not a regular feature. Classic dermatological findings in DM include Gottron’s papules, heliotrope erythema, the shawl sign, and facial erythema. The etiology of DM remains unknown; some studies have reported an association with histocompatability antigens, environmental agents (e.g. virus, drugs) and autoimmunity.1,2 Several autoantibodies have been identified, but their routine use in diagnosis has not yet been defined. These autoantibodies have been termed myositis-specific antibodies and include Anti-Mi-2, Anti-Jo-1, antisignal recognition protein and anti-Ku.2 Pemphigus foliaceus, which is the least severe form of pemphigus, is characterized by crusted, scaly sores, or fragile blisters. Oral or other mucocutaneous blisters do not occur in this disorder. Circulating antibodies in PF bind to desmoglein-1 protein rather than to the desmoglein-3 protein affected in pemphigus vulgaris (PV). Unlike the blisters seen in PV, the lesions in PF may itch and may easily be confused with eczema or non-specific dermatitis. We report a case of a 53-year old African American female who presented with DM and later developed PF. Narbutt et al. reported a similar case of a patient who presented with these two conditions.3