Umbilical spider's web

We report the case of a 38y old woman who consulted for chronic diffuse abdominal pain related to previous irritable bowel syndrome diagnosis. Physical examination showed nonblanching reddish hyperpigmented reticular peri-umbilical skin patch (figure 1). What's your diagnosis?

The diagnosis of erythema ab igne was made. Additional investigations confirmed repeated use of hot water bottles applied on abdominal wall for 3 weeks overnight for pain relief. Erythema ab igne is a pathognomonic cutaneous presentation of long-lasting exposure to heat sources (1). The pathophysiology of erythema ab igne remains uncertain. It has been suggested that heat exposure damages dermal vascular plexus and subsequent hemosiderin deposition leading to spider's web-like hyperpigmentation. Differential diagnosis of peri -umbilical dermatological manifestations includes digestive-related entities as caput medusae's sign (related to portal hypertension), Cullen's sign or Walzel's sign (related to acute pancreatitis); and non-digestive-related entities such as livedo reticularis (2). Erythema ab igne is well known from the dermatologists, mostly located on the lower limbs due to prolonged close exposition to heaters or on thighs due to laptop batteries (3). Erythema ab igne is usually of benign course, most often self-resolving after heat exposure discontinuation (3). We believe that it is of paramount to take into consideration the patients' pain and to propose an adapted management to avoid self-treatment.