Dermatitis Herpetiformis at a Glance
- Intensely itchy, chronic papulovesicular eruption distributed symmetrically on extensor surfaces.
- Characterized histologically by dermal papillary collections of neutrophils (microabscesses).
- Granular immunoglobulin (Ig) A deposits in normal-appearing skin are diagnostic for dermatitis herpetiformis.
- Most, if not all, dermatitis herpetiformis patients have an associated gluten-sensitive enteropathy.
- The rash responds rapidly to dapsone therapy and, in many patients, to strict adherence to a gluten-free diet.
Dermatitis herpetiformis (DH) is characterized by an intensely itchy, chronic papulovesicular eruption that usually is distributed symmetrically on extensor surfaces. The disease can be clearly distinguished from other subepidermal blistering eruptions by histologic, immunologic, and gastrointestinal criteria. The prevalence of DH in various Caucasian populations varies between 10/100,000 and 39/100,000 persons.1–3 Some reports suggests a 1.5:1 male to female ratio of DH patients. It may start at any age, including childhood; however, the second, third, and fourth decades are the most common. After presentation, DH persists indefinitely in most patients, although with varying severity. Two long-term studies of immunologically verified patients have suggested that the disease in approximately 10–12% of DH patients eventually remits.4,5
Patients with DH have an associated gluten-sensitive enteropathy (GSE) that is usually asymptomatic.
In 1884, Louis Duhring first described the clinical features and natural history of a polymorphous pruritic disorder that he called dermatitis herpetiformis; however, the critical elements in the pathogenesis of DH remained unknown until the 1960s.6 In 1966, Marks et al first noted a gastrointestinal abnormality in patients with DH.7 Shortly thereafter, it was shown that the lesion was reversible by avoidance of the dietary protein gluten.8,9 Initially, the intestinal abnormality was thought to be present in 60%–75% of DH patients. However, this view has been modified in two ways. First, the diagnostic criteria for DH have been delineated more precisely, and second, it can be shown that certain patients without apparent gastrointestinal pathology can be “induced” to develop gastrointestinal lesions by subjecting them to a large gluten intake; such patients have been said to have latent celiac sprue.10 Thus, most patients with DH have a gastrointestinal abnormality similar (if not identical) to celiac disease, however minimal that may be when the patient is ingesting a normal gluten load. These studies have all confirmed that gluten, a protein found in wheat, barley, and rye, plays a critical role in the pathogenesis of DH. Oats, long thought to contain gluten and play a role in inducing DH lesions, have been shown to be devoid of toxicity in patients with DH.11,12 As in celiac disease, there is an increased density of small bowel intraepithelial T cells with a γ/δ T-cell receptor in the jejunum of patients with DH.13 The finding that T-cell lines from patients with DH produce significantly more interleukin 4 (IL-4) than those from patients with GSE and that gut biopsies from symptomatic patients ...