This patient’s skin told a story before he could explain it. Across his abdomen spread a net-like rash: a map of reddish and brown tones that followed the exact pattern of the superficial blood vessels, as if someone had etched a mesh into his dermis. The diagnosis was Erythema ab igne, a condition caused by repeated and prolonged exposure to moderate heat sources that do not burn, but do cause damage.
The mechanism is silent and cumulative. Sustained heat degrades the elastic fibers of the dermis, dilates the capillaries, and causes a deposit of hemosiderin that permanently stains the skin. In this case, chronic abdominal pain had led the patient to apply hot water bottles or heating pads directly to the area for months, seeking relief. The result was this reticulated pattern that dermatologists recognize immediately.
What makes Erythema ab igne clinically relevant is not just the image, but what it implies: in older people or those with undiagnosed chronic pain, this rash may be the first visible sign of a serious underlying pathology, including abdominal masses or chronic pancreatitis. The skin, in this case, functioned as an involuntary marker of something the patient had been ignoring for some time.
