From the Guidelines
Yes, a negative Immunofluorescence (IIF) test result can occur in a patient with dermatitis herpetiformis. This is because the presence of circulating IgA anti-endomysial or anti-tissue transglutaminase antibodies in the serum is not always detectable in patients with dermatitis herpetiformis, as noted in studies such as 1. The diagnosis of dermatitis herpetiformis is primarily based on the presence of granular IgA deposits in the dermal papillae of uninvolved perilesional skin as shown by direct immunofluorescence, as stated in 1. Some key points to consider in the diagnosis and management of dermatitis herpetiformis include:
- The condition is characterized by herpetiform clusters of intensely itchy urticated papules and small blisters distributed on the extensor aspects of the elbows and knees and over the buttocks and on the scalp, as described in 1.
- Less than 10% of patients with DH have symptoms or signs of malabsorption but most have evidence of CD that responds to a GFD and relapses on gluten challenge, as noted in 1.
- A skin biopsy for direct immunofluorescence should be performed if dermatitis herpetiformis is strongly suspected clinically but serum IIF is negative, due to its higher sensitivity and specificity for the diagnosis. The risk of relapse in patients with negative IIF results is lower, ranging from 24% as mentioned in 1, highlighting the importance of considering both clinical presentation and diagnostic test results in managing the condition.
From the Research
Dermatitis Herpetiformis Diagnosis
- A negative Immunofluorescence (IIF) test result can occur in a patient with dermatitis herpetiformis, as demonstrated by a case study where a 7-year-old boy with dermatitis herpetiformis had negative direct immunofluorescence (DIF) findings for junctional IgA deposits in uninvolved skin 2.
- The diagnosis of dermatitis herpetiformis should be based on a combination of clinical, histologic, and immunologic data, rather than relying solely on the characteristic DIF pattern 2.
- Direct immunofluorescence testing for IgA has a sensitivity of 0.75 and a specificity of 0.951, but false negatives can occur, particularly in patients with a high clinical suspicion for dermatitis herpetiformis 3.
- Serum IgA anti-epidermal transglutaminase autoantibodies can be a useful marker for diagnosis of dermatitis herpetiformis in adult patients, with high sensitivity and specificity 4.
- Recent updates on direct immunofluorescence for diagnosing dermatitis herpetiformis suggest that the concept of DH may need to be revised, and that other factors such as C3 deposition at the dermal-epidermal junction should be considered 5.