Laptop Heat Causes Rare Toasted Skin Syndrome in a Boy

Key TakeawaysErythema ab igne (EAI), also known as toasted skin syndrome, is caused by repeated exposure to low-grade heat and does not cause acute burns. It typically presents as a reticulated, erythematous, or hyperpigmented lesion in the exposed area. Although traditionally associated with heating devices, laptops and other electronic devices can also cause prolonged heat exposure.A reticulated abdominal rash initially mistaken for a hematoma prompted extensive investigations before a targeted history revealed prolonged laptop-associated heat exposure. EAI should be considered in children and adolescents with unexplained reticulated skin lesions to avoid unnecessary investigations, including imaging, that involve ionizing radiation.The Patient and His HistoryA boy in early adolescence presented with a lesion in the right upper quadrant of his abdomen that had been present for approximately 1 week. Initially considered a hematoma, the lesion was flat and painless, without itching or discharge. It remained unchanged at first, but later darkened without improvement, prompting him to inform his parents. Neither the boy nor his parents could initially identify the cause.He reported no known trauma or recent illness and had no systemic, abdominal, or urinary symptoms. His vaccinations were up to date, and his growth and development were normal. His medical history was unremarkable.Findings and DiagnosisOn examination, the boy was clinically stable and showed a flat, approximately 15-cm brownish-red lesion in the right upper quadrant of the abdomen. Intersecting lines formed irregular circles, creating a reticulated lace-like pattern with poorly defined borders. There was no scaling. No other skin lesions, lymphadenopathy, or ecchymosis were identified, and the remainder of the physical examination was unremarkable.Initial laboratory tests showed no significant abnormalities. A chest x-ray showed a small, asymptomatic consolidation in the lower left lobe of the lung.During venipuncture, the boy reported that he had been playing and fighting with his brother the previous week and had been pushed into a chair. He withheld this information because he feared that his brother would be punished. This disclosure raised suspicion of traumatic injury.A CT scan showed no intra-abdominal lesion and confirmed the presence of a small pulmonary consolidation. The patient was discharged with a 5-day course of oral amoxicillin/clavulanic acid and instructions regarding warning signs that would require medical reassessment.Approximately 2 weeks after the initial evaluation, the patient returned because the lesion had progressed and because of pain on palpation. The erythema intensified, and a pink focus within the hyperpigmented area was consistent with superficial skin erosion. These changes prompted reassessment of the initial suspicion of hematoma.Although the initial questioning did not identify heat exposure, a more targeted history revealed that the boy was engaged in remote learning and regularly rested his laptop directly on his abdomen for up to 8 hours daily, often while the device was charging. The characteristic reticulated pattern and history of prolonged heat exposure supported the clinical diagnosis of EAI.The family was reassured of the benign nature of the condition. The patient was discharged with dressing and instructions to avoid further direct exposure to heat. A follow-up phone call with the father a few months later confirmed gradual improvement, with complete resolution of the lesion after removal of the heat source.DiscussionInitially, the differential diagnosis included livedo reticularis, cutaneous vasculitis, and trauma. Livedo reticularis was considered because of its reticulated pattern, but the absence of systemic manifestations and the localized distribution of the lesion made this diagnosis unlikely. Cutaneous vasculitis was considered because the lesion could represent purpura; however, the absence of associated signs, symptoms, and biochemical abnormalities argued against it. Trauma was considered after the patient reported being pushed; however, the diagnostic workup revealed no significant abnormalities. In addition, the absence of pain at presentation and the lesion’s progression were inconsistent with traumatic injury.EAI was diagnosed at the second visit, approximately 2 weeks after the initial evaluation. The diagnosis was based on the lesion’s progression and a targeted medical history, which revealed prolonged exposure to a low-intensity heat source.The literature indicates that EAI caused by laptop use is well recognized in adults but has rarely been reported in children and adolescents. Most cases result from prolonged heat exposure for weeks to months and typically affect the thighs.Reports published during the COVID pandemic indicated an increase in EAI among children and adolescents, attributed to remote learning and prolonged use of electronic devices that emit low-intensity heat. These reports underscore the importance of asking about potential sources of heat exposure.Compared with previously published cases, this case was similar in the lesion’s appearance and triggering factor but differed in its location and initial presentation. The lesion initially mimicked a traumatic injury, prompting imaging studies.EAI is usually benign and reversible, with lesions improving within weeks to months after removal of the heat source. Some hyperpigmentation may persist, particularly after prolonged exposure. Further testing is indicated if lesions do not resolve after the triggering factor has been eliminated or if atypical features suggest an alternative diagnosis.No pediatric guidelines are available for EAI. The diagnosis remains clinical and is based on the patient’s medical history and lesion characteristics.One limitation of this case was the lack of in-person follow-up because the family confirmed the resolution of the lesion over the phone.This case highlights the importance of considering EAI in children and adolescents presenting with reticulated erythematous lesions, particularly considering the increasingly common use of electronic devices.A medical history focused on exposure to low-intensity heat can help prevent misdiagnosis and unnecessary laboratory tests and imaging, thereby avoiding unnecessary exposure to ionizing radiation.Carla Vorsatz is a physician with postgraduate training in infectious and parasitic diseases from the Universidade Federal Fluminense in Brazil. She is currently pursuing additional postgraduate studies in medical expertise and psychiatry. Since 1996, she has run XSTZ | Medicina, Tradução & Linguagem, a company specializing in medical translation and scientific editing. She is the author of the Dictionary of Doubts and Difficulties in English Medical Translation, the Brazilian edition of the original Libro Rojo, by the Spanish physician Fernando Navarro. She conducts ongoing linguistic and terminological research focused on medical language. You can follow her work at Better Words, Better Diagnoses.This story was translated from Medscape’s Portuguese edition.