Dermatitis Herpetiformis (DH)

1. Overview

Dermatitis Herpetiformis (DH), also known as Duhring-Brocq disease, is a chronic autoimmune skin condition characterized by intensely itchy, blistering eruptions that cluster together. These blisters often occur in the elbows, knees, back, and buttocks.

2. Symptoms

• Skin manifestations:

• Variety: Blisters, vesicles, papules, plaques, and erythema.

• Blisters: Tense, surrounded by a red halo, clustered together.

• Precursors: Itching, burning, and pain.

• Location: Symmetrical, commonly found in elbows, knees, back, and buttocks.

• Progression: Erythema – vesicles – urticarial papules – blisters – crusting – rupture – erosions.

• Blisters: Corn-sized, round, shiny, containing a yellow fluid.

• Nikolsky sign (-): Skin peeling due to friction is rarely seen.

• General condition: Typically normal.

• Recurrence: Frequent.

3. Diagnosis

• Definitive Diagnosis:

• Varied lesions: As described in the symptoms section.

• Precursors, recurrence: As described in the symptoms section.

• KI test (+): Positive response to 50% potassium iodide (KI) solution in about 80-85% of cases.

• Histopathology: Sub-epidermal blisters, absence of acantholysis.

• Direct Immunofluorescence (DIF): Granular IgA deposition at the basement membrane, with potential for C3 and fibrinogen deposition.

• Differential Diagnosis:

• Pemphigus: Clinically similar to DH, but DIF shows IgG deposition.

• Herpes: Frequent recurrence, possible involvement of other lesions such as small blisters, pustules, and ulcers.

• Porphyria Cutanea Tarda: Blisters occur in outbreaks, lesions on exposed skin, darkening of skin in folds, and presence of Porphyrin in urine.

4. Diagnostic Gold Standard:

• DIF: Granular IgA deposition at the dermal papillae.

5. Histopathology:

• Absence of acantholysis.

6. Etiology

• Genetics: The disease has a genetic component, but the mechanism is not yet fully understood.

• Immune System: Caused by an autoimmune reaction where the body attacks antigens in the skin.

• Autoimmune Diseases: Glomerulonephritis, lupus, and pernicious anemia can be associated with DH.

• Gluten: A protein found in grains like wheat, barley, and rye, can trigger bowel inflammation.

• Steatorrhea: Fat malabsorption caused by enzyme deficiencies, leading to digestive disturbances.

• Malignancies: Malignant conditions, such as Hashimoto’s thyroiditis, may be linked to DH.

7. KI Test:

• Procedure:

• 1g KI ingestion: Dissolve KI in water and ingest once.

• Application of 50% KI ointment on normal skin: Apply to non-lesioned skin, avoiding sensitive areas.

• Results: A rash, itching, and blistering on the skin emerge within 24-48 hours.

8. Treatment

• Topical:

• For open lesions: Antiseptic solutions (e.g., povidone iodine).

• For dry lesions: Antibiotic ointments (e.g., mupirocin) or corticosteroid ointments (e.g., hydrocortisone ointment).

• Systemic:

• Dapsone: 100-300mg/day.

• Sulfapyridine: 1-1.5g/day (if Dapsone is not tolerated).

• Corticosteroids: Used when the above medications are ineffective.

• Cycline-group antibiotics: Can be used in combination with corticosteroids.

9. Diet

• Gluten-free: Eliminate grains containing gluten, including wheat, rye, and barley.

• Avoid seafood: High in iodine content.

• Avoid NSAIDs: Non-steroidal anti-inflammatory drugs.

10. Notes:

• Gluten: A protein found in grains like wheat, rye, and barley. Gliadin, a component of gluten, can trigger bowel inflammation, atrophy of digestive cells, and impaired intestinal absorption.

• Diagnosis: Duodenal biopsy and lifelong adherence to a gluten-free diet.

• Disease progression: It doesn’t affect overall health but can impact quality of life.

• Treatment: The goal is to control symptoms, minimize recurrences, and improve quality of life.

• Treatment adherence: Essential for disease control.

11. Conclusion:

Dermatitis Herpetiformis is a chronic autoimmune skin condition that can be managed with medication and a gluten-free diet. Accurate diagnosis and treatment adherence are crucial for controlling the disease.

Additional Notes:

• DH is more prevalent in individuals with celiac disease, an autoimmune disorder triggered by gluten.

• It’s important to understand that there is no cure for DH, but with proper management, individuals can live a full and healthy life.

• Consult with a dermatologist or healthcare professional for diagnosis and treatment options.