Chilblain lupus erythematosus is a rare form of cutaneous lupus erythematosus characterized by bluish red infiltrates in acral locations of the body mostly affecting middle-aged women. We recently described a familial form of chilblain lupus manifesting in early childhood caused by a heterozygous mutation in the TREX1 gene, which encodes a 3′-5′ DNA exonuclease. Thus, familial chilblain lupus represents the first monogenic form of cutaneous lupus erythematosus. Here we describe the unusual clinical course of this newly defined genodermatosis in an 18-year-old female member of the family in which familial chilblain lupus was originally described.