Table 1.

Differences between dermatitis derpetiformis and coeliac disease.

	Dermatitis Herpetiformis	Coeliac Disease
Gender	Slightly more males	Females predominate
Age at onset	Mainly adults	Children and adults
IgA-TG3 deposits in the skin	100%	0%
Small bowel villous atrophy	75%	100% *
IgA-TG2 deposits in the small bowel mucosa [36,37]	80%	up to 100% **
Prevalence in Finland and United Kingdom [18,19,38]	75 and 30 per 100,000	660 and 240 per 100,000
Incidence	Decreasing	Increasing
Response to a gluten-free diet [7,8,20]	Slow; months, in the beginning most patients need dapsone to control the rash	Rapid; days or weeks until gastro-intestinal symptoms end whereas small bowel villous atrophy may persist for many years
Long-term prognosis on a gluten-free diet [39,40,41]	Excellent	All-cause and lymphoma mortality may be increased

TG3 = epidermal transglutaminase, TG2 = tissue transglutaminase; * Potential coeliac disease with normal small bowel mucosa architecture, inflammation and positive TG2 serology also exist; ** Data still sparse.