Fire stains
Skin condition from prolonged heat exposure, also called toasted skin syndrome.
Erythema ab igne, sometimes called hot water bottle rash or toasted skin syndrome, happens when skin is exposed to heat for a long time. This ongoing infrared radiation can cause a lacy red pattern, darkening, flaking, and visible blood vessels. While some people feel mild itching or burning, the condition often goes unnoticed unless the skin color changes.
Quick Facts
- Temperature range causing condition
- 43 to 47 °C
Facts from the source article.
Causes
Various heat sources can cause this condition. Repeated application of hot water bottles, heating blankets, or heat pads for chronic pain, such as chronic back pain, is a common cause. Repeated exposure to heated car seats, space heaters, or fireplaces also contributes, particularly in elderly individuals who sit close to heaters. Occupational hazards affect silversmiths and jewelers (face exposed to heat) as well as bakers and chefs (arms, face). Resting a laptop computer on the thigh can induce the condition; modern laptops with powerful processors can reach 50 °C during operation, and temperatures between 43 and 47 °C are sufficient to cause it. In Kashmir, use of a kanger is associated with the condition, which also relates to kangri cancer. It is a classic finding in chronic pancreatitis and may appear in people with hypothyroidism or lymphedema.
Pathogenesis
The pathogenesis of erythema ab igne remains unknown. One proposal is that thermal radiation damages superficial blood vessels, leading to epidermal vascular dilation, which morphologically presents as the initial erythema. Red blood cell extravasation and hemosiderin deposition then appear clinically as hyperpigmentation in a reticular distribution. The net-like pattern of lesions may result from the distribution of affected blood vessels, predominantly in the superficial subcutaneous plexus of the papillary dermis.
Treatment
Initial treatment involves discontinuing contact with the heat source. Mild cases with slight redness may resolve after a few months. Severe cases with pigmented and atrophic skin are unlikely to resolve, and there is a possibility of squamous cell carcinoma or neuroendocrine carcinoma such as Merkel cell carcinoma forming. A persistent non-healing sore or growing lump within the rash warrants a skin biopsy to rule out skin cancer. For pre-cancerous changes, 5-fluorouracil cream has been recommended. Abnormally pigmented skin may persist for years; topical tretinoin or laser treatment may improve appearance.
Epidemiology
Erythema ab igne was once commonly seen in elderly individuals who stood or sat closely to open fires or electric heaters, but it has been reported in both young and elderly people. Women have a higher incidence than men. Widespread use of central heating has reduced overall incidence, but the condition is still found in people exposed to heat from sources such as heating pads, space heaters, hot water bottles, and electronic devices.
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