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Clinical Images  |   December 2012
Erythema Ab Igne
Author Notes
  • From Rush University Medical Center in Chicago, Illinois 
  • Address correspondence to Brian R. Poustinchian, DO, Rush University Medical Center, John H. Stroger Jr. Hospital of Cook County, 1901 W Polk St, Suite 911, Chicago, IL 60612-3723. E-mail: brian_poustinchian@rush.edu  
Article Information
Cardiovascular Disorders / Imaging / Clinical Images
Clinical Images   |   December 2012
Erythema Ab Igne
The Journal of the American Osteopathic Association, December 2012, Vol. 112, 808. doi:10.7556/jaoa.2012.112.12.808
The Journal of the American Osteopathic Association, December 2012, Vol. 112, 808. doi:10.7556/jaoa.2012.112.12.808
A 50-year-old woman with a history of meralgia paresthetica, Graves disease, and diabetes mellitus presented to our medical center with symptomatic hypoglycemia. On physical examination, a nonpruritic, macular, nonblanching, brown hyperpigmentation in a reticular pattern on the left anterior thigh (pictured) was noted. The patient reported chronic heating pad use over the affected area for several weeks for management of chronic pain. A dermatologist was consulted, and erythema ab igne (EAI) resulting from excessive heating pad usage was diagnosed. After the patient discontinued heating pad use, the rash improved but did not resolve. Repeated exposure to infrared radiation from heat or at levels insufficient to induce thermal burns can result in EAI.1 Mild cases of EAI regress after removal of the heat source, but topical retinoids and hydroquinone may be used to reduce hyperpigmentation.2 Although rare, squamous cell carcinoma and neuroendocrine carcinoma (ie, Merkel cell carcinoma) can arise from EAI.3 
   Financial Disclosures: None reported.
 
   Authors interested in contributing to “Clinical Images” should refer to the JAOA's “Information for Authors” at http://www.jaoa.org/misc/ifora.xhtml. Manuscripts should be submitted at http://mc04.manuscriptcentral.com/jaoa.
 
References
Miller K, Hunt R, Chu J, Meehan S, Stein J. Erythema ab igne. Dermatol Online J. 2011;17(10):28. http://dermatology.cdlib.org/1710/2011-05/28_2011-05/article.html. Accessed May 30, 2012.
Cardona LF, Parsons AC, Sanqueza OP. Erythematous lesions on the back of a man: answer. Am J Dermatopathol. 2011;33(2):199. [CrossRef]
Tan S, Bertucci V. Erythema ab igne: an old condition new again. CMAJ. 2000;162(1): 77-78. http://www.cmaj.ca/content/162/1/77.full. Accessed April 13, 2012.