What is toasted skin syndrome?

Medical News Today

01-07-2025

Toasted skin syndrome (TSS) is a skin condition that occurs following chronic exposure to moderate heat or infrared radiation. Another name for this condition is 'erythema ab igne', which is Latin for 'redness from fire'.In TSS, repeated direct exposure to heat sources like heat pads, hot water bottles, or heated car seats may cause the skin to become pink and mottled. It may be harder to see on dark skin. Continued exposure to the heat source causes this mottling to darken and take on a reticulated or lace-like pattern.Most cases of TSS eventually resolve after a person stops exposing their skin to the heat source. However, people with severe TSS may experience permanent skin hyperpigmentation. Having TSS also increases the risk of certain types of skin cancer.This article provides an overview of TSS and outlines the condition's symptoms, causes, and risk factors. We also describe how doctors diagnose and treat TSS, and consider the outlook for people with this condition.OverviewToasted skin syndrome (TSS) is a type of skin hyperpigmentation that develops following repeated exposure to moderate heat or infrared radiation. Potential sources of such include:heat pads or hot water bottlesheated car seatsspace heaterslaptops resting on thighsIn TSS, repeated direct contact with a heat source causes damage to the skin's elastic fibers and superficial blood vessels, resulting in hemosiderin deposition and overproduction of the pigment melanin. This process results in a type of mottled or lace-like hyperpigmentation.Hemosiderin deposition occurs when red blood cells leak and break down, and iron from those cells leaves a stain in the skin, causing brownish patches. It contributes to the mottled or net-like darkening seen in toasted skin syndrome. Removing the heat source can cause TSS to spontaneously resolve. However, repeated exposure to the heat source can lead to permanent hyperpigmentation. It may also lead to the progression of certain skin cancers, such as:Merkel cell carcinomabasal cell carcinomasquamous cell carcinomaSymptomsAs a 2021 case study explains, the skin lesions associated with TSS may not appear immediately after exposure to a heat source. Instead, they may take several weeks or months to appear.According to the American Osteopathic College of Dermatology (AOCD), the first sign of TSS is typically pink, mottled skin. With continued exposure to the heat source, the mottled areas may take on a reticulated or lace-like appearance, with the hyperpigmented areas becoming red, violet, or brown in color.Causes and risk factorsToasted skin syndrome occurs when the skin comes into direct contact with a moderate-intensity heat source for a sustained period. This causes damage to the skin's elastic fibers and superficial blood vessels, releasing hemosiderin and melanin, which causes the affected area of skin to become hyperpigmented. Historically, TSS was more common among industry workers like bakers and metalworkers, who frequently had close exposure to heat sources. More recent risk factors for TSS include:resting a laptop on the thighsapplying heat pads or hot water bottles to the skinapplying a 'sauna belt' to help treat abdominal obesityusing a heated blanketusing a heated car seatusing a space heaterA 2021 review adds that TSS is more common among women compared to men, and is also more common among people with chronic pain.DiagnosisWhen diagnosing TSS, doctors will consider a person's symptoms alongside any history of heat exposure. In some cases, doctors may take a small sample of the affected skin and examine it under a microscope to look for characteristic signs of TSS. This type of test is called a biopsy, and it can help to rule out other conditions with similar symptoms. According to a 2018 case study, these conditions may include:livedo reticularislivedo racemosacutis marmoratacutis marmorata telangiectatica congenitaTreatmentA 2018 case study notes that TSS typically resolves after a person stops exposing their skin to the heat source. However, since TSS increases the risk of certain skin cancers, individuals who have TSS with skin ulceration or non-healing wounds should undergo a skin biopsy to rule out skin cancer.According to the AOCD, more advanced cases of TSS may persist for years, and some may even be permanent. Some individuals with permanent hyperpigmentation may have concerns about the appearance of their skin. Treatments that may help to improve the appearance of TSS hyperpigmentation include:the topical treatment '5-fluorouracil'the topical retinoid 'tretinoin'laser therapyOutlookAccording to a 2021 review, TSS usually resolves within weeks or months of removing the heat source, although the rash may become permanent. The review adds that in some cases, TSS may develop into a type of skin cancer, such as:cutaneous squamous cell carcinomaMerkel cell carcinomaheat-induced basal cell carcinomaAnyone who has received a diagnosis of TSS and has continued concerns about their skin can talk to a doctor or dermatologist for further information and advice.SummaryToasted skin syndrome (TSS) or 'erythema ab igne' is a type of skin hyperpigmentation that occurs when the skin persistently comes into direct contact with a moderate-intensity heat source, or infrared radiation. In TSS, heat causes the skin's elastic fibers and superficial blood vessels to break down, releasing hemosiderin and melanin. This results in patchy hyperpigmentation that may darken over time and take on a lace-like or mottled appearance.Doctors diagnose TSS according to a person's symptoms and history of heat exposure. In some cases, doctors may take a skin biopsy to rule out other conditions.The main treatment for TSS is removal of the heat source, and this method resolves most TSS cases within months. However, severe cases can cause permanent hyperpigmentation, and also increase the risk of certain skin cancers. Anyone who has concerns about this can talk to a doctor or dermatologist for further advice.