| • | antigen = smooth muscle cell endomysium |
Clinical:
| • | intensely pruritic therefore rarely find primary lesions (find crusted and eroded lesions) |
| • | grouped (herpetiform) papules, vesicles, and urticarial plaques |
| • | symmetrically on extensor surfaces: elbows, buttocks, knees |
Systemic:
| • | on small bowel biopsy 60-70% have histologic features of gluten protein found in various grains such as wheat, rye, barley, and oats (not in corn or rice) sensitive enteropathy |
| • | only 5-10% have clinical symptoms of diarrhea, bloating, and abdominal pain |
Histology:
| • | subepidermal blister with neutrophilic abscesses in the dermal papillae |
| • | DIF: granular deposits of IgA at the tips of the dermal papillae; even on non-involved skin (but deposits may be focal, so that multiple biopsies may be needed) |
| • | IgA anti-endomysial (smooth muscle) antibodies found in sera of patients with DH (but basement membrane antigen unknown?) |
| • | Screening Test for DH: tissue transglutaminase antibodies or anti-endomysial antibodies (but gold standard is biopsy with immunofluorescence) |
Treatment:
| • | exquisitely responsive to dapsone (main complication = hemolysis: occurs to some degree in all patients, can be catastrophic in G6PD deficiency) |
| • | IgA disappears with gluten-free diet, but not with meds |
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