investigations
Last reviewed 01/2018
The investigation of dermatitis herpetiformis should include the following:
- blood tests for celiac disease
- immunology study
- IgA antiendomysial antibodies
- IgA anti-tissue transglutaminase antibodies (sensitivity 98.5%, specificity 98%)
- useful additional test if serology supports the diagnosis of coeliac disease include
- FBC
- blood film
- haematinics (vitamin B12, folate, ferritin)
- urea and electrolytes may
- thyroid function test – due to the association of thyroid disease with both coeliac disease and dermatitis herpetiformis
- skin biopsies
- lesional skin of patients with DH will reveal epidermal vesicles and blisters associated with accumulation of neutrophils at the papillary tips on histopathological study
- a second biopsy consisting of peri-lesional skin (within 2cm of the blister) is used for direct immunofluorescence
- is the gold standard for the diagnosis of DH
- will show granular IgA deposits along the dermal-epidermal junction and on top of the dermal papillae
If blood tests point towards a diagnosis of celiac disease, a referral to secondary care is recommended.
Note:
- once the diagnosis is confirmed, DH should be considered as a cutaneous manifestation of and pathognomonic for, coeliac disease. Hence, duodenal or jejunal biopsies are not considered necessary for further diagnosis
Reference:
- (1) Jakes AD, Bradley S, Donlevy L.Dermatitis herpetiformis. BMJ. 2014;348:g2557.
- (2) Antiga E, Caproni M.The diagnosis and treatment of dermatitis herpetiformis. Clin Cosmet Investig Dermatol. 2015;8:257-65.
- (3) Primary Care Dermatology Society (PCDS). Dermatitis herpetiformis (Accessed 20/03/2017)