A few years ago I saw a patient with a similar rash (BF Curtis et al. Gastroenterol 2017; 153: 355-6) and texted a picture to a dermatology colleague who quickly asked me whether my patient was using heating packs/heating pads on her abdomen.
This rash, termed, “erythema ab igne,” develops due to excessive heat exposure. Also, it has been called “toasted skin syndrome.” Over time, if heat is not continued to abdomen, in most cases, the skin reverts to normal in this benign asymptomatic condition.