A patient presents with an itchy rash to the elbow that started a week prior to presentation. After initially becoming red, the rash developed small blisters then the blisters ruptured, leaving small sores. There is no warmth or fluctuance to the area. The patient saw his primary care physician 5 days ago and was prescribed topical steroids which had no effect on the rash. He also notes that he has been having diarrhea and stomach cramping lately. WBC count and sed rate are normal.
What is the diagnosis, how is it treated, and what other disease is it associated with?
I’ll post the answer below the picture on Friday.
Answer: Dermatitis Herpetiformis
Kudos to anon for the perfect answer.
Dermatitis herpetiformis is associated with celiac disease. In fact, some clinicians assert that a diagnosis of dermatitis herpetiformis can be used as a “backdoor diagnosis” to celiac disease.
DH occurs most commonly in the extensor surfaces of the joints, on the buttocks, and on the back of the neck, but can occur anywhere on the body. It is often misdiagnosed, being confused with drug eruptions, contact dermatitis, dishydrotic eczema, and even scabies.
DH is diagnosed by skin biopsy, but multiple biopsies must be taken from diseased and healthy skin as at least one biopsy must show IgA deposits in the dermal layers under immunofluorescence in order to confirm the diagnosis.
Long-term treatment is a gluten-free diet, but dapsone (a drug used to treat leprosy – more in-depth information here) may be used to treat the rash in resistant cases or in flares.