D2I2.
autoimmune

Dermatitis herpetiformis

herpetiformis (DH) is a blistering skin condition, characterised by intensely itchy blisters filled with a watery fluid. DH is a manifestation of coeliac disease, although the exact causal mechanism is not known. DH is neither related to nor caused by herpes virus; the name means that it is a skin having an appearance similar to herpes.

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Plain-language summary adapted from Wikipedia. Not medical advice.