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| ORIGINAL ARTICLE |
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| Year : 2021 | Volume
: 8
| Issue : 1 | Page : 25-29 |
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Dermoscopic analysis of idiopathic guttate hypomelanosis: a cross-sectional study
Harish M. R., Shashikumar B. M. MD (DVL) , Priyanka R Magod, Deepadarshan K.
Department of Dermatology, Mandya Institute of Medical Sciences, Mandya, Karnataka, India
| Date of Submission | 20-Feb-2020 |
| Date of Decision | 04-Apr-2020 |
| Date of Acceptance | 27-Jul-2020 |
| Date of Web Publication | 07-Apr-2021 |
Correspondence Address:
Dr. Shashikumar B. M.
Associate Professor, OPD room no.13, RDL first floor, Department of Dermatology, MIMS, Nehrunagar, Mandya – 571401, Karnataka
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/Pigmentinternational.Pigmentinternational_
Background: Idiopathic guttate hypomelanosis (IGH) is a common pigmentary disorder encountered in older age group, causing cosmetic disfigurement with considerable psychological impact. Diagnosis is generally based on history and clinical features. In the situation of diagnostic dilemma, dermoscopic examination is the quick and easiest method to solve the clinical uncertainty and thereby avoid unnecessary biopsies. Objectives: The aims of the study were to describe the varied clinical presentations and to enumerate the dermoscopic features of IGH. Methods: Study was conducted after obtaining approval from Institutional Ethics Committee. All the patients presenting with IGH attending the Department of Dermatology were examined and enrolled for the study after taking written informed consent. Each subject was evaluated by detailed personal history, clinical examination and dermoscopic examination. Results: A total of 100 patients of IGH were included in the study. The most affected age group was 46–65 years (52%). Females were most commonly affected with M: F ratio 1:1.17. Different dermoscopic patterns of IGH documented were amoeboid (58.2%), feathery (19.1%), petaloid (14.5%) and nebuloid (8.2%). Ten percent of the patients showed more than one patterns. Conclusion: Dermoscope aids in evaluation of different patterns of IGH lesions, which helps to differentiate it from other hypopigmented conditions with considerable overlap in the site, morphology and clinical features. Dermoscopic analysis makes it easier to diagnose the disorder and subsequently plan for the appropriate treatment.
How to cite this article:
M. R. H, B. M. S, Magod PR, K. D. Dermoscopic analysis of idiopathic guttate hypomelanosis: a cross-sectional study. Pigment Int 2021;8:25-9 |
| Introduction | |  |
Depigmentation of the skin can be caused by a number of local and systemic conditions. Most of these lesions resemble each other clinically and have to be differentiated from various other diagnoses. Idiopathic guttate hypomelanosis (IGH) is a commonly acquired, benign leukoderma. It has to be differentiated from skin lesions which have a potential stigmatizing effect such as vitiligo.[1]
Morphologically, IGH looks similar to other depigmented skin lesions including vitiligo. It usually affects the geriatric population (>50 years) and has an obscure etiopathogenesis. The IGH lesions are characterized by hypopigmented or depigmented macules and patches. Their clinical appearance makes it difficult to diagnose and differentiate from other conditions.[2] Dermoscopy, a non-invasive, in vivo technique for the microscopic examination of pigmented skin lesions, has the potential to improve the diagnostic accuracy.[3]
Dermoscopy helps to visualize the different patterns which are characteristic for particular disease hence it makes it easier to diagnose the disease. There are very few studies that include dermoscopic evaluation of IGH, hence the present study was undertaken to describe the dermoscopic features of IGH.
The main objectives of our cross-sectional study were to describe the varied clinical presentations of IGH and to enumerate the various dermatoscopic features of IGH.
Methodology
The study was conducted for a period of 3 months after obtaining permission from institutional ethical committee in 100 patients presenting with IGH to outpatient Department of Dermatology fulfilling the inclusion criteria after taking informed consent. The clinical history pertaining to all the patients were recorded as per proforma. Complete dermatological examination and systemic examination were carried out. The dermoscopic evaluation was done using 3 Gen Dermlite III DL3N polarized dermoscopey with 10x magnification and pigment boost enhancement and findings were captured in OnePlus 6T mobile and analysed.
Inclusion criteria
- Patients with idiopathic guttate hypomelanosis lesions.
- Patients who gave informed consent.
Exclusive criteria
- Patients with generalized vitiligo and albinism were excluded. Also patients who were on or received the treatment for IGH within past 15 days were excluded.
- Patients with post-inflammatory hypopigmentation in the area near or surrounding the IGH lesions were excluded.
- Patients associated with chronic skin conditions and active infection around the lesions.
- Patients who were severely ill and debilitated were excluded.
Statistical analysis
Data were collected, analysed and tabulated. The results were statistically described in terms of distribution and duration of lesions, mean± standard deviation (±SD) and frequency of dermoscopic patterns when appropriate.
| Results | | |
There were 54 females and 46 males in the study. Average age of the patients was 57.53 years with ranged from 25 years to 87 years. Patients belonged to Fitzpatrick skin type IV and V. The proportion of patients among different age groups is depicted in [Figure 1]. Family history was present in 8% of patients. Positive history of excessive sun exposure was found in 9% patients. IGH lesions were distributed predominantly over lower limbs in 36%, followed by presence over all four limbs in 34%, both trunk and all four limbs in 28% of patients, and in the upper limbs in 2% patients. | Figure 1 The proportion of number of patients among different age groups.
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Dermoscopy of IGH lesions demonstrated white structureless areas with glow depicting absence of pigmentation. It had various patterns including amoeboid, feathery, petaloid and nebuloid patterns in 58.2%, 19.1%, 14.5%, 8.2% patients respectively. Ten (10%) patients had presence of more than one type of dermoscopic patterns. Perilesional pigmentation was found in 24% of the patients and 15% had faint perifollicular pigmentation.
Age of the patients and mean duration of IGH lesions is presented in [Table 1]. The amoeboid pattern [Figure 2](a) identified by the amoeba-like pseudopods extending at periphery was most commonly observed dermatoscopic pattern in our study. Feathery pattern [Figure 2](b) showing feather-like striations extending into surrounding skin, petaloid pattern [Figure 2](c) with well-defined borders and nebuloid pattern showing round or oval cloudy dense white pattern with indistinct margins, merging into surrounding skin were seen in the descending order. | Figure 2 Pigment boosted polarized light of 10x magnification with skin contact dermoscopic images of IGH lesion showing (a) amoeboid pattern with well-defined hyperpigmented margin containing pseudopod extension (arrow), (b) feathery pattern with defined and feathery margins and irregular pigmentation (arrow), (c) petaloid pattern which is fairly well-defined with irregular polycyclic pigmented margin (arrow), and (d) nebuloid pattern with oval cloudy dense white pattern with indistinct margins merging into the surrounding skin (arrow).
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Distribution of dermoscopic patterns among different age groups were as follows: feathery pattern (50) was observed in younger age groups and amoeboid (57.6), petaloid (63.9) and nebuloid (64.9) were seen in older age groups.
The total number of patients with diabetes mellitus were 18. The duration of diabetes ranged from 10 years in one patient, 15 years in 3 patients, 20 years and 25 years in four patients each, and 30 years in six patients.
| Discussion | | |
IGH is a relatively common acquired and age-related benign leukoderma usually affecting the elderly population.[1] IGH is primarily a clinical diagnosis made on the basis of history and physical examination. Physical examination should be performed under both visible light and UV light of about 365-nm wavelength (Wood’s lamp) preferably, as these lesions may not be conspicuous under visible light in light-skinned individuals.[4] It has to be distinguished in clinical practice from other depigmented and hypopigmented conditions such as vitiligo, leprosy, and pityriasis versicolor.[3]
On dermoscopy guttate vitiligo lesions also show white stuctureless areas with glow, but they differ from IGH findings by having sharp border, perilesional and perifollicular pigmentation which are better appreciated and deeply pigmented. Nebular pattern is more common than amoeboid pattern in cases of guttate vitiligo. Vitiligo lesions also demonstrate trichrome appearance, starburst pattern, tapioca sago pattern, comet tail appearance and microkoebnerization which is absent in a lesion of IGH. Hypopigmented lesions of leprosy on dermoscopy reveals altered pigment network, fine scales, and decrease in number of white globules which represent the sebaceous glands and flattened perifollicular hypopigmentation. Dermoscopy of pityriasis versicolor lesions demonstrate white structureless areas without glow, faint pigment network and white scales, scales are perifollicular, patchy and/or prominent in the skin lines, separated into lines when the lesions stretched.[5],[6]
There is a close similarity in the histological findings in IGH and those seen in vitiligo with definite differentiation between the two entities nearly impossible. Histopathology of IGH are characterized by flat epidermis, absent rete ridges and a basket weave stratum corneum. The basal layer reveals a markedly decreased to absent melanin with decreased but not absent numbers of melanocytes at the dermoepidermal junction which will signify the hypopigmentation or depigmentaion of the lesion respectively and glow is due to reflection of the light from the underlying dermal collagen. The fibroblasts, collagen and elastic fibres are normal appearing in the layer of the dermis.[3]
Even though the precise etiopathogenesis of IGH has not been deciphered and still remains obscure, various factors can be postulated. For example, since we notice an increasing incidence in the elderly, degenerative changes that are intrinsic to normal aging can play a role in its causation. Other hypotheses include the concept that this occurs secondary to cumulative chronic sun exposure, or begins due to repeated microtrauma to the skin.[2]
In our study, there was a higher preponderance of women presenting with IGH lesion, about 54 in number when compared to 44 men. This gender predilection is higher than that reported by Ankad et al.[3] This can be due to the fact that females are more concerned for cosmetic reasons. This increasing prevalence with aging and female preponderance is consistent with reports by Min‐Kung Shin et al.[7] who observed an increasing incidence in those over 40 years of age and a higher number of females 56% over 44% males in their study.
The sun-exposed areas are involved most frequently, especially the extensor forearms and pretibial areas, with relative sparing of the trunk and face.[1] Histopathological and ultrastructural studies have demonstrated solar elastosis in almost 70% of the IGH lesions, a histologic marker of chronic UV exposure.[8] In addition, perivascular monocytic infiltration has also been reported in the lesions, which hints toward the inflammatory nature of IGH.[4] Chronic sun exposure predisposing to formation of IGH was found in 9% of our patients.
Genetic predisposition has been proposed to be an etiologic factor, as there is development of IGH on sun-protected areas and in younger patients and the frequency of IGH is high in patients with positive family history as seen in some studies,[9] but in our study, only 8% of patients presented with a positive family history.
Additionally, we attempted to correlate the number of patients with diabetes and their duration of disease. We report that there was an increasing number of patients developing IGH as their duration of diabetes increased.
On clinical examination, IGH usually presents as multiple, well-circumscribed, asymptomatic, polygonal, white macules which are symmetrically distributed on sun-exposed areas. The most common locations include extensor forearms and shins. Skin lesions can range anywhere from 2 to 8 mm in diameter and often delineated by the skin furrows. Occasionally they may measure up to 2.5 cm.[4]
Bambroo et al.[3] and Ankad et al.[6] appreciated four patterns in the dermoscopy of IGH namely nebuloid, petaloid, feathery and amoeboid. We observed similar patterns in our study. The younger age groups predominantly showed the feathery pattern. The older age groups were found to have amoeboid, petaloid or nebuloid patterns. While, nebuloid pattern was seen in patients with longer duration of skin lesions, the petaloid pattern was observed in patients with shorter duration of skin lesions which was in contrary to study done by Ankad et al, where feathery pattern was seen in patients with longer duration of lesions and nebuloid pattern in those with lesser duration of lesions.
Limitations
Further studies need to be done to correlate the relation between the number of lesions of IGH with duration of diabetes mellitus. Histopathological correlation with dermoscopic findings were not done.
| Conclusion | | |
IGH has been well studied in terms of clinico-epidemiology and histopathology but not explored much in the field of dermoscopy. Dermoscopy makes it possible for complete assessment of lesions and study subtle features that are invisible to naked eye. In IGH, dermoscopy is poorly utilized and there is a scarcity of research studies. We observe that dermoscopy is a powerful tool at our disposal that can uncover the nuances and subtleties in the diagnosis of IGH.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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| 6. | Bambroo M, Pande S, Khopkar U. Dermoscopy in the differentiation of idiopathic guttate hypomelanosis (IGH) and Guttate vitiligo. In: Khopkar S, editor. Dermoscopy and Trichoscopy in Diseases of the Brown Skin. Atlas and Short Text. 1st ed. New Delhi: Jaypee Brothers Ltd; 2012. p. 97‑103. |
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| 8. | Juntongjin P, Laosakul K. Idiopathic guttate hypomelanosis: a review of its etiology, pathogenesis, findings, and treatments. Am J Clin Dermatol 2016;17:403-11. |
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[Figure 1], [Figure 2]
[Table 1]
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