What are the other Names for this Condition? (Also known as/Synonyms)

• Granny’s Tartan
• Hot Water Bottle Rash
• Toasted Skin Syndrome

What is Erythema Ab Igne? (Definition/Background Information)

• Erythema Ab Igne (EAI) is a skin reaction that occurs on regular exposure of the skin to infrared (heat) radiation for long durations. The name translate as “redness from fire”
• This may take place while sitting near fireplaces and working in certain industry that results in exposure to heat. The exposure may even occur from heated car seats, due to sitting on them for long periods
• Erythema Ab Igne is generally seen during adulthood. The cause of development of the condition is not well-established
• Any part of the body may be affected. Erythema Ab Igne lesions have a reddish discoloration and mesh-like or mottled pattern on the skin. A few longstanding cases are known to be associated with skin cancers
• Erythema Ab Igne may be treated using topical creams and gels and laser therapy. In general, the prognosis is good with appropriate treatment

Who gets Erythema Ab Igne? (Age and Sex Distribution)

• Erythema Ab Igne may occur at any age, although most cases are observed in older adults
• Both males and females may be affected. However, generally, females are affected more than males
• Individuals of all racial and ethnic background can be affected

What are the Risk Factors for Erythema Ab Igne? (Predisposing Factors)

The risk factors for Erythema Ab Igne include any factor that leads to heat exposure. These may include the following:

• Sitting close to electric space heaters, fireplaces, and other heat sources
• Use of heating pads for shoulder pain or back pain
• Exposure to heat at workplaces, such as to individuals, who include restaurant chefs, blacksmiths, glassblowers, individuals dealing with furnaces without adequate protection, and sitting near a printer vent
• Heated car seats
• Placing hot electronic devices on laps; holding such hot devices

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Erythema Ab Igne? (Etiology)

• The exact cause of development of Erythema Ab Igne is presently unknown
• The condition may be due to reaction of skin to the constant heat (infrared component of heat) radiation, resulting in inflammation and increased blood supply to the affected region

It is important to note that Erythema Ab Igne is non-contagious and it cannot be transmitted from one individual to another.

What are the Signs and Symptoms of Erythema Ab Igne?

The signs and symptoms of Erythema Ab Igne (EAI) include:

• The lesions are usually red (erythematous) and have a lace-like network pattern (reticulated)
• Longstanding EAI can lead to pigment changes; hypopigmentation or hyperpigmentation
• The lesions may itch leading to scratching and bleeding
• Burning sensation may be noted
• Ulcers can develop easy bleeding
• Atrophy of skin (skin breaks and bleeds)
• Usually, only the area of heat exposure is affected

How is Erythema Ab Igne Diagnosed?

A diagnosis of Erythema Ab Igne may involve the following:

• A thorough medical history assessment and complete physical examination; a history of long duration heat exposure may be established
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Skin biopsy: A skin biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Erythema Ab Igne?

Erythema Ab Igne is a benign condition that does not cause any significant complications. However in some individuals, the following complications may be noted:

• Cosmetic issues resulting in emotional stress
• Secondary bacterial and fungal infection: Continuous itching and scaling of the skin will create skin moistness, providing a suitable environment for bacteria and fungi to grow and thrive
• There is a risk for skin cancers, such as Kangri cancer (a type of squamous cell carcinoma of skin occurring in the Indian state of Kashmir), developing at these sites after a long period. Merkel cell carcinomas have also been reported in fields of skin affected with Erythema Ab Igne

How is Erythema Ab Igne Treated?

The treatment measures adopted for Erythema Ab Igne may include:

• Avoidance of heat exposure; providing adequate protection against such heat sources
• Use of topical retinoid creams
• Administration of antifungal or antibiotic medication, if necessary
• Laser therapy for increased skin pigmented areas

Follow-up care with regular screening and check-ups are important and encouraged.

How can Erythema Ab Igne be Prevented?

The preventive measures for Erythema Ab Igne may include:

• Avoiding long-term direct exposure to heat; avoiding sitting too near to such sources, especially during the cold seasons
• Individuals, who are constantly exposed to heat sources as part of their profession, should take suitable protection against such heat radiation sources
• Ensuring that the industries strictly comply with implementation of prevalent statutory codes on occupational safety measures, especially with respect to workplace exposure to heat
• Undertaking routine screening of individuals working in environments where such exposures are evident

What is the Prognosis of Erythema Ab Igne? (Outcomes/Resolutions)

• The prognosis for Erythema Ab Igne is usually good in a majority of cases, since it is a benign condition that may only present some cosmetic issues
• However, in some rare cases, it may be associated with malignancy; and hence, close clinical monitoring is necessary

Additional and Relevant Useful Information for Erythema Ab Igne:

• Do not pick or pop any blisters, for doing so can affect the healing process and may result in secondary infections
• Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition
• The presence of dirt on the body is not a causative factor for the condition. However, it helps to be clean and hygienic, which may help the condition from getting worse