Acrodermatitis continua of Hallopeau is a clinical phenotype of DITRA: evidence that it is a variant of pustular psoriasis.

Acrodermatitis continua of Hallopeau (ACH) is a rare, chronic, sterile, pustular eruption that predominantly affects the fingertips with nail involvement. While some consider ACH a distinct entity, many believe it to be a variant of pustular psoriasis, especially as cases of ACH progressing to generalized pustular psoriasis (GPP) have been reported. Recently, recessively inherited mutations in the IL36RN gene, which encodes interleukin-36 receptor antagonist (IL-36Ra), have been demonstrated to be the cause of familial GPP, a condition termed DITRA (deficiency of IL-36Ra). Here, we identified a homozygous missense mutation c.338C>T (p.Ser113Leu) in the IL36RN gene in a male patient with ACH, as well as in his sister who had a history of GPP.