Erythema Ab Igne: Toasted Skin Syndrome Author Affiliations Are Listed 1 1 1 Vincent Ly, DO, James E

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Ly et al. HCA Healthcare Journal of Medicine (2021) 2:2 https://doi.org/10.36518/2689-0216.1149

Case Report

Erythema ab igne: Toasted Skin Syndrome Author affiliations are listed 1 1 1 Vincent Ly, DO, James E. Vandruff, DO, Julia Fashner, MD, MPH, FAAFP at the end of this article. Abstract Correspondence to: Introduction Julia Fashner, MD, MPH, Erythema ab igne is a benign skin condition caused by long-term exposure to infrared radi- FAAFP ation and/or heat. Erythema ab igne begins as a mild erythema over the previously exposed areas and develops into an erythematous reticulated hyperpigmentation with scaling and University of Central telangiectasias. Florida College of Medicine/HCA GME Clinical Findings Consortium A 55-year-old female presented to the primary care clinic with concerns due to the develop- Ocala Regional Medical ment of a rash on her lower back in the previous 1 to 2 weeks. She had a history of chronic back pain and was using conservative treatment for pain management, including daily use Center Family Medicine of a heating pad for 15 minutes every hour. Residency 1431 SW First Ave. Interventions Blitzer Building, Suite 7 There is no definitive therapy for erythema ab igne. Elimination of the heat source may Ocala, FL 34471 reverse the erythema and hyperpigmentation. (Julia.fashner@ Outcome hcahealthcare.com) The patient was counseled regarding the importance of limiting and/or discontinuing the use of the heating pad to facilitate resolution of the rash. The patient did not return to the clinic and resolution of the rash was not confirmed.

Keywords erythema ab igne; erythema; erythema/pathology; hot temperature/adverse effects; hyperpigmentation/etiology Introduction tological condition is based on clinical findings Erythema ab igne (erə’THēmə ab ignē) is a and supporting history. benign skin condition caused by long-term exposure to infrared radiation or heat. In Latin, Historically, erythema ab igne has been asso- it translates to “redness by fire”.1,2 This condition ciated with occupations that experience pro- has many other names such as hitze melanoses longed exposure to heat, such as bakers and 4 (German for “melanosis induced by heat”), metal foundry workers. It was also common ephelis ignealis, heat-induced circumscribed in individuals with chronic exposures to fires 4 dermal melanosis, livedo reticularis e calore and prior to the development of central heating. toasted skin syndrome.2 The temperature required to produce the rash is lower than what is required to cause a Erythema ab igne begins as a mild erythema burn, typically between 43 and 47°C or 107.6 5,6 over the previously heat-exposed areas and de- and 116.6°F. With the increasing use of por- velops into an erythematous, reticulated hyper- table electronic technologies, there have been pigmentation with scaling and telangiectasias reported cases associated with exposure to present over the same area.3 Generally, the rash heated car seats, heating pads, space heaters, 5 is reported to be asymptomatic and often is hot laptops or hot water bottles. an incidental finding. Diagnosis of this derma-

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Figure 1. Examination of the rash demonstrated diffuse erythema with hyperpigmented reticulated telangiectasia. Case Presentation rash. The patient did not return to the clinic This case pertains to a 55-year-old female with and resolution of the rash was not confirmed. a history of chronic back pain, fibromyalgia and Additionally, due to the lack of follow-up to ob- morbid obesity. The pain had been located in tain a biopsy if necessary, a definitive diagnosis the middle to lower back and did not radiate of erythema ab igne was not possible. but was increasing in intensity and frequen- cy. The patient lived a sedentary lifestyle but Treatment reported less mobility secondary to her wors- There is no definitive therapy for erythema ab ening back pain. The patient was status-post igne. Elimination of the heat source may re- thoracolumbar nerve block injection 4 months verse the erythema and hyperpigmentation.5,7 prior and had plans for a repeat injection. For cases that are chronic or improve minimally after elimination of the heat source, the use She presented to the primary care clinic with of topical steroids or tretinoin and hydroqui- concerns due to the development of a rash on none may reduce the discoloration.7 Five-flu- her lower back over the previous 1 to 2 weeks. orouracil has been shown to help destroy the (Figure 1) The patient expressed worry that the atypical cells that make up the reticulated rash rash would prevent her from receiving a second of erythema ab igne.7 Mesoglycan with topical injection for back pain symptom management. flavonoids has also been shown to reduce the She denied recent trauma or osteopathic/ discoloration.8-10 chiropractic manipulation. She noted she was seated or lying in bed for 20 to 22 hours a day. The patient was using conservative treatment Discussion A review of the literature found the majority of for pain management, including a heating pad cases were reported in middle-aged to elderly on her back. She reported attempting to keep adults suffering from chronic musculoskeletal the heating pad applied for only 15 minutes but pain, with lesions appearing after application of often was applying the heating pad every hour hot water bottles or heating pads.1-17 In younger throughout the day. Besides cosmetic con- adult and pediatric populations, the incidence cerns, the rash was asymptomatic. of erythema ab igne was more frequently associated with the use of heat-generating porta- The patient was counseled regarding the im- ble electronic devices such as laptops or space portance of limiting or discontinuing the use of heaters.1,11 the heating pad to facilitate resolution of the

98 Ly et al. (2021) 2:2. https://doi.org/10.36518/2689-0216.1149

The pathophysiology of the rash has not been ab igne since cold exposure causes the dis- fully established, but some studies indicate coloration as opposed to warm exposure in that thermal radiation exposure induces dam- erythema ab igne.9 Cutis marmorata telangiec- age to the superficial blood vessels, which leads tasia is characterized by persistent reticulated to epidermal vascular dilation.11 The hyper- blanching erythema with possible atrophy. This pigmentation, which can occur in a reticular condition is congenital and can be associated distribution, is thought to be due to deposition with vascular malformation, limb asymmetry, of hemosiderin.4,12,13 One study that obtained neurologic or ocular abnormalities. One distin- biopsies for pathological evaluation proposed guishing feature includes occasional ulceration radiant (infrared) energy enters the dermis development along the lines of atrophy. Ad- and activates lysosomes.2 The enzymes be- ditionally, due to its congenital nature, it can come free to diffuse into the tissue and digest be accompanied by other anomalies including susceptible substances such as collagens and syndactyly, port-wine stain, clubfoot, etc.9,13 elastic fibers. These condense with chronic exposure and produce elastosis or degenerative Although erythema ab igne is largely a benign changes with increased deposition of elastin, incidental finding, there are reports of asso- resulting in the classic characteristic rash of ciated insidious pathologies. There have been erythema ab igne.2 Other theories attribute the reported cases of erythema ab igne developing rash to repeated exposures to infrared radia- cutaneous malignancies such as squamous cell tion. The repeated exposures lead to a marked carcinoma or Merkel cell carcinoma.5,17 In other erythema, hyperpigmentation and occasional studies, erythema ab igne was a dermatolog- epidermal atrophy.14 ical finding in patients with underlying malignancies such as colorectal, pancreatic, gastric, Histologically, erythema ab igne resembles renal, breast and/or hematologic malignancies.3 actinic keratosis with the epidermis showing It has been suggested that the underlying atypical cells. There is also associated accumu- malignancy may serve as the source of chronic lation of dermal elastic tissue, which is an early pain that leads patients to use heating devices sign of both UV radiation and heat-induced that will lead to development of the rash.17 skin damage.14 Conclusion Erythema ab igne can resemble other skin Heat is often recommended by physicians as conditions, including livedo reticularis, livedo conservative treatment for musculoskeletal or racemose, cutis mamorata and cutis marmora- 9,15 chronic pain. It is important to consider erythe- ta telanglectasia. Livedo reticularis is charac- ma ab igne as a potential complication when terized by a mottled reticular pattern and often recommending this relatively benign treatment has purple discoloration. These findings are due or as a potential diagnosis in patients with to impaired blood flow and occurs after expo- an unexplained rash who are utilizing heating sure to cold temperature. These symptoms will 9 modalities for pain control. With increasing resolve as the tissue rewarms. Like erythema use of portable electronics, practitioners need ab igne, livedo racemose is also characterized to revisit safe practice guidelines of heat- by a violaceous net-like rash, but the rash is generating technologies. Differentiating this more widespread as opposed to being limited benign condition from similar looking rashes to a specific exposed area. Additionally, the will ultimately prevent exposing patients to shape is irregular, and this skin condition is also unnecessary testing, costly treatment and commonly associated with pathological condi- 16 unnecessary referrals to specialists. Due to the tions. risk of underlying malignancies associated with erythema ab igne, it is important the condition Cutis marmorata is the physiological form of is properly diagnosed and followed in the pri- livedo reticularis and is a normal response of mary care setting. the body.9 This form is often seen in infants and resolves with age. Livedo reticularis may be indicative of underlying pathology, includ- Conflicts of Interest ing lupus, vasculitis, toxins, etc. These types of The authors declare they have no conflicts of pathology are differentiated from erythema interest.

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The authors are employees of Ocala Regional spective multicenter study. J Cosmet Derma- Medical Center, a hospital affiliated with the tol. 2020;19(7):1774-1779. https://doi.org/10.1111/ journal’s publisher. jocd.13210 11. Riahi R, Cohen PR. What Caused This Hyper- This research was supported (in whole or in pigmented Reticulated Rash On This Man’s Back? The Dermatologist. 2013;21(1). part) by HCA Healthcare and/or an 12. Cavallari V, Cicciarello R, Torre V, et al. HCA Healthcare affiliated entity. The views Chronic heat-induced skin lesions (erythe- expressed in this publication represent those of ma ab Igne): ultrastructural studies. Ultra- the author(s) and do not necessarily represent struct Pathol. 2001;25(2):93-97. https://doi. the official views of HCA Healthcare or any of org/10.1080/01913120117614 its affiliated entities. 13. Morrison M, Cotton J, LaFond A. Reticulated erythematous patch on teenager’s foot. J Fam Pract. 2014;63(9):537-539. Author Affiliations 14. Tan S, Bertucci V. Erythema ab igne: an old con- 1. University of Central Florida College of dition new again. CMAJ. 2000;162(1):77-78. Medicine/HCA GME Consortium, Ocala 15. Kienast AK, Hoeger PH. Cutis marmorata telan- Regional Medical Center Family Medicine giectatica congenita: a prospective study of 27 Residency, Ocala, FL cases and review of the literature with pro- posal of diagnostic criteria. Clin Exp Dermatol. References 2009;34(3):319-323. https://doi.org/10.1111/j.1365- 1. Brzezinski P, Ismail S, Chiriac A. Radiator-in- 2230.2008.03074.x 16. Sajjan VV, Lunge S, Swamy MB, Pandit AM. Li- duced erythema ab igne in 8-year-old girl. Rev vedo reticularis: A review of the literature. Chil Pediatr. 2014;85(2):239-240. https://doi. Indian org/10.4067/s0370-41062014000200015 Dermatol Online J. 2015;6(5):315-321. https://doi. 2. Finlayson GR, Sams WM Jr, Smith JG Jr. Er- org/10.4103/2229-5178.164493 17. Jones CS, Tyring SK, Lee PC, Fine JD. De- ythema ab igne: a histopathological study. J velopment of neuroendocrine (Merkel cell) Invest Dermatol. 1966;46(1):104-108. https://doi. org/10.1038/jid.1966.15 carcinoma mixed with squamous cell carci- 3. Cross F. On a turf (peat) fire cancer: malignant noma in erythema ab igne. Arch Dermatol. 1988;124(1):110-113. https://doi.org/10.1001/arch- change superimposed on erythema ab igne. Proc derm.1988.01670010074024 R Soc Med. 1967;60(12):1307-1308. https://doi. org/10.1177/003591576706001223 4. Baruchin AM. Erythema ab igne—a neglected entity?. Burns. 1994;20(5):460-462. https://doi. org/10.1016/0305-4179(94)90043-4 5. LeVault KM, Sapra A, Bhandari P, O’Malley M, Ranjit E. Erythema Ab Igne: A Mottled Rash on the Torso. Cureus. 2020;12(1):e6628. Published 2020 Jan 11. https://doi.org/10.7759/cureus.6628 6. Miller K, Hunt R, Chu J, Meehan S, Stein J. Ery- thema ab igne. Dermatol Online J. 2011;17(10):28. Published 2011 Oct 15. https://escholarship.org/ uc/item/47z4v01z 7. Sahl WJ Jr, Taira JW. Erythema ab igne: treatment with 5-fluorouracil cream. J Am Acad Der- matol. 1992;27(1):109-110. https://doi.org/10.1016/ s0190-9622(08)80818-3 8. Gianfaldoni S, Gianfaldoni R, Tchernev G, Lotti J, Wollina U, Lotti T. Erythema Ab Igne Successful- ly Treated With Mesoglycan and Bioflavonoids: A Case-Report. Open Access Maced J Med Sci. 2017;5(4):432-435. Published 2017 Jul 18. https:// doi.org/10.3889/oamjms.2017.123 9. Joshi AR, Golova N, Lakhiani C. Reticulated rash on boy’s lower extremities. Contemp Pediatr. 2019;36(2):36-34. 10. Ozturk M, An I. Clinical features and etiology of patients with erythema ab igne: A retro-

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