Categories
Uncategorized

Dermatitis herpetiformis

1816

Manifests with a pruritic blistering rash.

Estimated incidence rate ranges from 0.8-3.5 cases per 100,000 person-years.

The disease most frequently affects individuals of Northern European descent with a slight male predominance.

 

Mean age of onset the fourth or fifth decade. 

Autoimmune blistering disorder associated with a gastroenteropathy.

Aso known as Duhring-Brocq disease.

Autoimmune blistering skin disease that manifests as pruritic papules and vesicles.

Associated with celiac disease.

More than 90% of cases have a small bowel biopsy results demonstrating evidence of gluten sensitive enteropathy.

 

Most cases are of subclinical celiac disease. 

Diagnosed by presence of granular IgA deposits at the dermoepidermal junction of uninvolved skin.

Histopathologic findings include microabscesses or subepidermal blisters with neutrophilic infiltrates at dermal papillary tips.

Associated with celiac disease, autoimmune thyroid disease, and pernicious anemia.

Considered an extra intestinal manifestation of celiac disease.

Diagnosis depends on presence of granular immunoglobulin IgA in uninvolved skin.

In susceptible patients, it develops as a result of complex immune response involving both the intrinsic and extrinsic pathways, arising from sensitivity to gliadin peptides and tissue transglutaminase.

IgA deposition occurs in the dermis, with immune complex formation, and neutrophil chemo taxis, causing proteolysis and blister formation.

Associated with excoriations, erythematous lesions, urticarial plaques and vesicles.

Skin lesions located on the extensor surfaces of the buttocks, knees, elbows and back.

Skin biopsy shows deposition if IgA immunoglobulin in the upper papillary dermis.

Most patients are asymptomatic gastrointestinal wise but more than 90% have a gastroenteropathy on endoscopic examination.

Increased expression of HLA-1, HLA-B8, HLA-DR3, and HLA-DQ2 and HLA-DQ8 haplotypes.

These haplotypes are virtually universally present in patients with DH.

Treatment includes dapsone and gluten free diet.

An uncommon autoimmune cutaneous eruption.

In more than 90% of cases, small bowel biopsy specimens demonstrate evidence of gluten-sensitive enteropathy.

Most cases of gluten-sensitive enteropathy are subclinical.

With an estimated incidence rate ranging from 0.8 to 3.5 cases per 100,000 person-years.

Most frequently affects individuals of northern European descent.

There is a slight male predominance.

The mean age of disease onset is reported to be in the fourth or fifth decade

Genetic risk factors exist, as HLA-DQ2 and HLA-DQ8 haplotypes are virtually universally present in patients with DH and are associated with a genetic predisposition to the disease.

In susceptible individuals, DH develops as a result of a complex immune response involving both intrinsic and extrinsic pathways.

There is sensitivity to gliadin peptides and tissue transglutaminase, leading to IgA deposition in the dermis, immune complex formation, neutrophil chemotaxis, ultimately causing proteolysis and blister formation.

The disease is characterized by intermittent eruptions of grouped, intensely pruritic papules and vesicles.

Lesions most commonly occur on the elbows, dorsal forearms, knees, scalp, back, and buttocks bilaterally.

It may be associated with intense pruritus, so that excoriations and erosions may predominate over vesicles.

Oral involvement may occur.

Oral involvement may be associated with development of mucosal erythematous macules, papules, vesicles, and erosions, as well as tooth enamel degradation.

Early, biopsy specimens may show collections of neutrophils with or without eosinophils.

Subsequently at approximately 2 days, subepidermal vesicles may form which later coalesce to form blisters.

Diagnosis is confirmed with microscopy demonstrating granular deposits of IgA in the papillary dermis, and is supported by the presence of circulating IgA antibodies to epidermal transglutaminase, tissue transglutaminase, and/or endomysium.

A selective IgA deficiency occurs at a higher frequency in patients with celiac disease, and, measurement of serum immunoglobulin G to tissue transglutaminase and endomysium may be useful.

Dapsone and a strict gluten-free diet are effective treatment options.

Dapsone is thought to cause inhibition of myeloperoxidase, thereby leading to an anti-inflammatory and immunomodulatory effect.

Mild disease flares are expected and may occur while on dapsone therapy, andthe dose of dapsone should not be increased in such cases.

Dapsone can be slowly tapered over several months; tapering too quickly may result in disease flares.

Can usually remove dapsone after 6 months of clinical remission.

A lifelong condition characterized by intermittent flares, and sustained remission requires a strict gluten-free diet and/or treatment with dapsone.

Only in 10% to 15% of cases is there a sustained remission despite discontinuation of dietary and pharmacologic therapy.

Patients are at risk of developing other autoimmune disorders, most commonly autoimmune thyroid disease, type 1 diabetes mellitus, and pernicious anemia.

Leave a Reply

Your email address will not be published. Required fields are marked *