Saturday, January 01, 2011
Dermatitis herpetiformis is a chronic, intensely pruritic
disorder characterized by symmetrically distributed bullae or
erosions, deposition of IgA in the dermal papillae, and evidence of
gluten-sensitive enteropathy. Only 10% of patients experience
spontaneous remission. The therapeutic strategy is control of
pruritus and at least most of the skin lesions.
Following glucose-6-phosphate dehydrogenase (G6PD) screening,
the drug of choice is dapsone 100 mg/day. Expect a dramatic
clinical response within 4-5 days. Reevaluate the patient after 2
weeks, and increase dapsone to 200 mg/day if clinical improvement
is inadequate. Check the complete blood count (CBC) every 2 weeks
as the dose is increased.
- Continue the amount of dapsone required for clearing for 2
weeks, and then taper the drug by halving the dose every 2 weeks.
Maintain the patient on the least amount of dapsone required for
control of lesions. Although most patients require between 50 and
150 mg daily, some patients are controlled on significantly lower
doses (25 mg dapsone per week). Once the appropriate dapsone dose
is found, the CBC is checked on a 6-month basis.
- Sulfapyridine, supplied in 500-mg tablets, may be used in an
initial dose of 1-2 g/day in patients who cannot tolerate dapsone.
Taper to the minimum required dose with is usually 1.0-1.5
- Combination therapy: If partial control is obtained on maximal
doses of sulfapyridine (4 g/day), a small dose of colchicines may
be added (0.6 mg once or twice daily).
- Gluten-free diet: Because dermatitis herpetiformis is gluten
dependent, most patients will respond to a gluten-free diet.
Clinical response usually requires the patient to be on a rigid
gluten-free diet for 6-12 months. Although not as ideal, even
partial avoidance of gluten is helpful. To obtain dietary
directions, refer the patient to a dietician skilled in treating
patients with celiac disease. A successful dietary regimen requires
an intelligent, highly motivated patient who dines at home. Most
patients who adhere to their diet will be able to reduce their
medication dose by 50% or more.
Complications and Undesired Consequences
- The diagnosis of dermatitis herpetiformis should be
re-evaluated in patients who do not respond to appropriately
administered sulfone therapy.
- Screen patients prior to sulfone therapy for anemia and G6PD
deficiency to avoid further anemia or severe drug-induced
- Follow the CBC at regular intervals in all patients during
adjustment of sulfone dose. Once treatment dose is established,
these tests and a white blood count needs to be checked once or
- Patients with dermatitis herpetiformis are at increased risk to
develop lymphoma of the GI tract. A gluten-free diet will prevent
- While a gluten-free diet takes 6 months to have efficacy and
allow reduction or discontinuation of medication, gluten exposure
may be followed within hours or days by a flare of the skin