Efficacy of Targeted Phototherapy in Idiopathic Guttate Hypomelanosis

Kannan, P (2020) Efficacy of Targeted Phototherapy in Idiopathic Guttate Hypomelanosis. Masters thesis, PSG Institute of Medical Sciences and Research, Coimbatore.


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BACKGROUND: Idiopathic guttate hypomelanosis (IGH) is a commonly acquired benign leukoderma that is characterized by multiple discrete, hypo-, or depigmented 2 to 5mm macules. The most commonly affected areas are the extremities. The pathogenesis of IGH is unknown and remains controversial. The cause of IGH has been theorized to involve senile degeneration of melanocytes, photoaging or sunlight exposure, and trauma. Because etiologic evidence is lacking, IGH is most commonly considered idiopathic. Idiopathic guttate hypomelanosis is considered a benign condition, but is often cosmetically disturbing for patients. Prevalence of IGH has been reported to increase with age, sun exposure, genetics (HLA-DQ3), autoimmunity, trauma, xerosis, and the use of “body scrubbers”. It has been reported to occur in 47% to 87% of dermatologic subjects more than the age of 40. Treatment for IGH is difficult; there is no “gold standard” for treatment of IGH. Although the underlying mechanism of IGH is unknown, the authors hypothesize that melanocytic stimulation from UVB will result in repigmentation of IGH. AIM OF THE STUDY: To determine the effectiveness of targeted phototherapy for repigmentation of idiopathic guttate hypomelanosis. MATERIALS AND METHODS: A total of 12 patients with IGH lesions were included in this study. Extent and number of lesions were counted and recorded, after getting informed written consent from IGH patients, minimal erythema dose (MED) was calculated. Initial dose was started at 1 MED and incrementation of 0.5 MED was given on subsequent visits. Phototherapy was administered weekly twice for 6 weeks for a total of 12 sitings. A single x ray sheet with multiple punched out holes of varying sizes was prepared. The sheet was placed on top of the lesions before administering phototherapy to minimize surrounding pigmentation. Patients were assessed for extent of repigmentation at the end of 6th week. RESULTS: This pilot study included 12 patients (7 females and 5males) with idiopathic guttate hypomelanosis. Majority of the lesions were seen over legs and few over thighs and arm. Lesions over lower extremities were selected. 5 patients were male and 7 patients were females. Two patients lost follow up. Total of 122 lesions were selected for targeted phototherapy out of which 24% (29/122) lesions had 0-50% of improvement, 46% (56/122) lesions had 50-75 % of improvement and 30% (37/122) of lesions had 75-100% of improvement. The improvement was not uniform in all patients. Lesions seen over the individual patients responded differently. Some lesions had good improvement and other lesions had mild improvement in same patient. Erythema and pigmentation over the surrounding skin were the common side effects observed in our study. No patients developed severe reactions like blisters. CONCLUSION: Targeted phototherapy is a novel safe and effective treatment option for IGH with acceptable cosmetic outcomes.

Item Type: Thesis (Masters)
Additional Information: 201730353
Uncontrolled Keywords: Idiopathic guttate hypomelanosis (IGH), targeted phototherapy, UVB phototherapy.
Subjects: MEDICAL > Dermatology Venereology and Leprosy
Depositing User: Subramani R
Date Deposited: 05 Feb 2021 15:47
Last Modified: 05 Feb 2021 15:47
URI: http://repository-tnmgrmu.ac.in/id/eprint/13894

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