Vesicular and Bullous Diseases

Dermatitis herpetiformis (DH) is a chronic pruritic vesicular rash commonly occurring on the extensor surfaces and is a manifestation of gluten sensitivity.

In adults, DH is twice as common in males.

In children, females are more commonly affected.

Most patients with DH are of northern European descent.

DH rarely occurs in Asians and Africans.

Severe, unremitting itching and burning are a constant feature. The classical rash consists of clustered vesicles symmetrically distributed on the elbows, knees, sacrum, and base of the scalp.

Intact vesicles are often destroyed by scratching and are often difficult to identify.

Patients may also develop nonspecific papules, urticaria, hemorrhagic macules, and erosions.

Rarely, the rash may be limited to the face.

Oral lesions are uncommon.

Ninety percent of patients have gluten-sensitive enteropathy.

The severity of skin disease does not correlate with degree of intestinal involvement.

DH is associated with thyroid disease (e.g., Hashimoto's thyroiditis) and enteropathy-associated lymphoma.

Enteropathy-associated lymphoma risk is reduced with a gluten-restricted diet.

Skin biopsies should be performed for standard histology and direct immunofluorescence.

Immunoglobulin A (IgA) deposits are found in the dermal papillae in 90% of cases.

Circulating IgA antiendomysial antibodies are found in the serum of 70% of patients, not on a gluten-free diet.

Serum IgA antiendomysial antibody titers correlate with severity of jejunal villous atrophy.

Serum IgA level and IgA antitransglutaminase-2 antibodies should be ordered in patients with suspected DH.

If IgA antitransglutaminase-2 antibodies are increased, then antiendomysial antibodies should be ordered.

DH is a chronic condition with spontaneous remission in 30% of people.

Systemic iodides may aggravate DH.

DH is recurrent but usually is well controlled with oral sulfones, such as dapsone, or a strict gluten-free diet.

Arthropod bite

Scabies (when excoriated, is also intensely itchy; look for burrows)

Atopic dermatitis

Lichen simplex chronicus

A gluten-free diet can control DH and allow decreased requirement for oral medication.

Gluten is a protein found in wheat, rye, and barley.

Rice, oats, and corn do not contain gluten.

Treatment does alter severity of symptoms, but does not alter disease duration.

Oral dapsone 100 to 150 mg every day is the drug of choice and typically relieves itching and burning within 48 to 72 hours.

Daily maintenance dose of dapsone varies from 25 to 200 mg per day.

Obtain a pretreatment glucose-6-phosphate dehydrogenase level. Patients with low levels are at increased risk for hemolysis.

Sulfapyridine 500 to 1500 mg per day is effective in some patients as an alternative to dapsone.

Tetracycline 500 mg one to four times per day, minocycline 100 mg twice a day, and nicotinamide 500 mg two to three times a day have been reported to be helpful in some cases.

Intense unremitting itch, unresponsive to prednisone, suggests scabies or DH.

Immunofluorescence confirms the diagnosis of DH.

Although DH is a blistering disease, bullae are rarely seen; pruritus induces scratching, and removes vesicles and small bullae, leaving only crusted papules and small erosions.

Pemphigus vulgaris is a rare, life-threatening, autoimmune, intraepidermal blistering disease, involving the skin and mucous membranes.