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Comment & Response
April 2018

Pustular Eruption (Iododerma?) in a Patient With Cancer Treated With Complementary and Alternative Medicine—Reply

Author Affiliations
  • 1Department of Dermatology, University of Iowa Hospitals and Clinics, Iowa City
  • 2Department of Dermatology, Iowa City VA Health Care System, Iowa City
JAMA Dermatol. 2018;154(4):496. doi:10.1001/jamadermatol.2017.6165

In Reply We thank Dr Nwabudike for his kind remarks regarding our recent Observation. Herein, we provide additional details concerning our diagnosis of iododerma while expanding our opinion on the role of Hoxsey herbal therapy in the outcome of this case.

A diagnosis of iododerma is made based on clinical evaluation and exposure history because there are no universally recognized pathognomonic findings.1 Additional laboratory studies in our patient, including complete blood cell count, white blood cell differential, serum creatinine level, and blood urea nitrogen level were all within normal limits. Aerobic cultures of the pustules recovered normal skin flora. The patient was euthyroid based on history and physical examination, a diagnosis corroborated by a normal level of thyroid-stimulating hormone and consistent with escape from the Wolf-Chaikoff effect.2 The collective findings in this case strongly favored a diagnosis of iododerma over a differential that included bacterial folliculitis, herpes simplex virus infection, pustular psoriasis, Sweet’s syndrome, pemphigus vegetans, and a dimorphic fungal infection.1,3 Perhaps most importantly, the eruption abated following removal of potassium iodide from his “brown tonic.” To date, the pathophysiology of iododerma remains poorly understood.1 We can only speculate that disease severity in some forms of iododerma correlates with the magnitude of changes in blood iodine levels, not the iodine level itself. Thus, after many months of regular “brown tonic” use, sporadic consumption of seafood may have given rise to the acute-on-chronic elevations in blood iodine level that triggered the relatively mild and intermittent flares of iododerma observed in our patient.

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