Potassium iodide in the treatment of disseminated granuloma annulare

Potassium Iodide for Cutaneous Inflammatory Disorders: A Monocentric, Retrospective Study

OBJECTIVES

Potassium iodide (KI) is a medication that has been used for decades in dermatology and it is mentioned as a treatment option in all major dermatology textbooks. Yet, there is little recent information on its efficacy. In our study, we wanted to retrospectively evaluate the therapy response to KI in our patients.

METHODS

The hospital information system was searched for patients treated with KI at the Department of Dermatology (University Hospital Zurich) in the last 20 years (January 1, 1998 to December 31, 2017). A total of 52 patients were found and, subsequently, 35 patients were included in our study.

RESULTS

KI was prescribed for the following skin conditions: erythema nodosum, disseminated granuloma anulare, necrobiosis lipoidica, nodular vasculitis, cutaneous sarcoidosis, and granulomatous perioral dermatitis/ rosacea. The median duration of KI intake was 5 ± 7.7 weeks (range 1-26). The global assessment of efficacy by the treating physician showed an improvement of disease in about a third of all patients. No response was seen in 14 patients and 9 even had a progression of disease. An adverse event was documented in 16 cases.

CONCLUSIONS

Our findings show that an improvement was reached in only about a third of all cases. High response rates with only mild side effects (in 16 out of 35 patients) were observed.

Granuloma Annulare: A Focused Review of Therapeutic Options

Granuloma annulare (GA) is a benign inflammatory disease associated with many conditions such as malignancy, trauma, thyroid disease, diabetes mellitus, and HIV infection. Common clinical subtypes include localized GA, generalized GA, subcutaneous GA, perforating GA, and patch GA. There exists an abundance of literature on GA, yet we know relatively little about its exact etiology and even less about its treatment. The paucity of conclusive data on effective treatment options is largely because the majority of published studies are limited to small case reports, case series, and retrospective studies. As such, there does not yet exist a gold standard of care to guide clinical management. Depending on the clinical subtype, the clinical prognosis for GA can vary. The localized variant generally self-resolves within 2 years without treatment, whereas the generalized form is more chronic and less responsive to treatment. This focused up-to-date review serves to summarize the latest therapeutic options available for GA.

Use of potassium iodide in dermatology: updates on an old drug

Potassium iodide, as a saturated solution, is a valuable drug in the dermatologist's therapeutic arsenal and is useful for the treatment of different diseases due to its immunomodulatory features. However, its prescription has become increasingly less frequent in dermatology practice. Little knowledge about its exact mechanism of action, lack of interest from the pharmaceutical industry, the advent of new drugs, and the toxicity caused by the use of high doses of the drug are some possible explanations for that. Consequently, there are few scientific studies on the pharmacological aspects, dosage and efficacy of this drug. Also, there is no conventional standard on how to manipulate and prescribe the saturated solution of potassium iodide, which leads to unawareness of the exact amount of the salt being delivered in grams to patients. Considering that dosage is directly related to toxicity and the immunomodulatory features of this drug, it is essential to define the amount to be prescribed and to reduce it to a minimum effective dose in order to minimize the risks of intolerance and thus improve treatment adherence. This review is relevant due to the fact that the saturated solution of potassium iodide is often the only therapeutic choice available for the treatment of some infectious, inflammatory and immune-mediated dermatoses, no matter whether the reason is specific indication, failure of a previous therapy or cost-effectiveness.

Etiology, diagnosis, and therapeutic management of granuloma annulare: an update

Granuloma annulare (GA) is a common cutaneous disorder classically presenting as annular groups of skin-colored to erythematous papules without epidermal change localized to the dorsal hands and/or feet. In addition to the localized form, there are variants including generalized (including generalized annular GA, disseminated papular GA, and atypical generalized GA), subcutaneous, and perforating GA, providing for a wide spectrum of clinical lesions. The etiology of GA remains unknown and several systemic associations have been proposed but not proven, including diabetes mellitus, malignancy, thyroid disease, and dyslipidemia. The diagnosis of GA relies on clinicopathological correlation, with a skin biopsy confirming the histological features of the disease, including palisading granulomas, collagen degeneration, mucin, and a lymphohistiocytic infiltrate. Localized GA is often asymptomatic and self-limited within 2 years; however, the patient may desire treatment for cosmetic reasons, with topical and intralesional corticosteroids as the mainstays of therapy. When GA is generalized, disseminated, or atypical, a more thorough medical workup for underlying diseases may be considered depending on the physical examination, a thorough review of systems, comorbidities, and clinical suspicion. Treatment is often challenging for generalized GA, especially because of its recalcitrant nature and a lack of evidence-based therapy. Over 30 different treatments have been described for GA with variable results; however, the majority of these have been single case reports, small case series, or retrospective studies. Reported treatments for GA include topical, intralesional, intramuscular, and oral medications (steroidal vs. non-steroidal); biologic agents; surgical interventions; phototherapy; and laser treatments. When selecting a systemic therapy for a patient with GA, multiple variables must be considered, such as baseline blood evaluations, comorbidities, drug interactions, compliance, adverse effect profiles, prior treatments, and reproductive status. This evidence-based review will focus on the advances made in the twenty-first century regarding the etiology, diagnosis, and therapeutic management of GA.

Granuloma anulare

Granuloma annulare is a benign self-limiting disease of unknown origin, characterized by dermal papules tending to form annular shapes. It belongs to the granulomatous inflammatory skin diseases characterized by histomorphologically detectable granulomas. In addition to localized variants, generalized or disseminated variants also exist. The disease is often asymptomatic and does not require therapy in every case. Established therapies for localized forms of granuloma annulare are glucocorticosteroids, cream PUVA and cryosurgery. Antimalarials, antileprotics, retinoids, fumarates, UVA1 phototherapy and photochemotherapy are of value in disseminated cases. Recent case reports demonstrate the successful treatment of granuloma annulare with topical calcineurin antagonists or imiquimod and with the systemic administration of biologicals.

Treatment of disseminated granuloma annulare with a 5-lipoxygenase inhibitor and vitamin E

Histologically, granuloma annulare (GA) is a common non-infectious necrobiotic granulomatous reaction pattern that correlates with a number of different, but relatively specific clinical presentations. The cause or causes of GA are unknown: when localized, it is usually self-limiting, but it may be persistent when disseminated. We present three women who had had disseminated GA for more than 1 year. One patient had previously been treated with isotretinoin with no response. All three patients were treated with vitamin E 400 IU daily and zileuton 2400 mg daily. All responded within 3 months with complete clinical clearing. The anti-inflammatory and immune regulatory effects of vitamin E and zileuton may be an effective treatment in some patients with prolonged disseminated/generalized GA.

Potassium iodide in dermatology: a 19th century drug for the 21st century-uses, pharmacology, adverse effects, and contraindications

Potassium iodide (KI) is a useful drug in the dermatologic armamentarium. It is successfully used for inflammatory dermatoses, most notably erythema nodosum, subacute nodular migratory panniculitis, nodular vasculitis, erythema multiforme, and Sweet's syndrome. KI is also successfully used for cutaneous and lymphocutaneous sporotrichosis. The precise mechanism by which KI acts is unknown. Although many minor side effects are common with this drug, major side effects can occur in pregnant patients and those with a history of kidney or thyroid disease. This article reviews the pharmacology, mechanism of action, indications, contraindications, and adverse effects of KI as a therapeutic agent.