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Hypopigmented skin lesions in childrenOnly 14 pages are availabe for public view
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Abstract
Hypopigmented lesions are considered important dermatoses in daily practice. Skin biopsy, KOH examination, and several laboratory tests could help in the diagnosis. However, some of these approaches are invasive, inconclusive and not always available. Dermoscopy in hypopigmented lesions is limited to case reports and very few researches and still there are no defined dermoscopic criteria in hypopigmented lesions.
Our aim was to identify the dermoscopic signs of diagnostic value in some common hypo- pigmented skin lesions in children.
Full history, clinical examination and dermoscopic examination (by handheld Dermlite 4 dermoscope) were done to all patients.
This study showed that the most common hypopigmented skin lesion in children was pityriasis alba; representing 37.3% of the patients, followed by vitiligo in 28%, nevus depigmentosus 14.7%, tinea versicolor 12% and postinflamatory hypopigmentation 8%.
Dermoscopic examination of the pityriasis alba showed hypopigmented macules with fine scales that are commonly distributed within and outside the macules. The hair inside the patches was of normal color. There was no sharp margin to differentiate the hypopigmented patch from the surrounding skin. These features were seen in all cases of pityriasis alba. In addition, 30 % of cases demonstrated erythematous changes within and surrounding the macules and patches.
The most common dermoscopic features in patients of vitiligo were, a diffuse white glow in 90.5% of cases, perilesional hyperpigmentation in 54.8% of cases, perifollicular hyperpigmentation in 23.8% of cases, leukotrichia in 35.7% of cases. The pigmentary network within the lesions was absent in 23(54.8%), reduced in 15(35.7%) and reverse in 4(9.5%), lesional and perilesional telangiectasia were present in 42.9% of cases. All of the lesions were not scaly in this study. Regarding the pattern in dermoscopy, there were different patterns seen in this study in order of frequency as follows: star burst pattern (71.4%), trichrome pattern (54.7%), polka dot pattern (52.4%) and comet tailing of the lesion (28.6%).
According to our study, perilesional hyperpigmentation and well-defined border are the most common finding present in stable disease while star burst pattern, comet-tail, trichrome pattern and polka dot pattern are the most commonly seen in unstable vitiligo.
Dermoscopy of hypopigmented nevus in this study showed that irregular and serrated border was the prominent feature. The borders also showed pseudopods pattern protruding into the normal skin in 86.4% of lesions. Perifollicular hyperpigmentation, perieccrine hyperpigmentation, and lesional erthyema were present in (27.3%), (18.2%), (22.7%), respectively. Hair within the patches were of normal colors, and there was no peripheral hyperpigmentation and scales in all cases.
The characteristic dermoscopic feature of tinea versicolor was diffuse hypopigmented blotches (fairly defined) with fine scales taking various distribution as perifollicular scaling, patchy scaling, skin lines scaling, peripheral scaling, and diffuse scaling in 13 (72.2%), 16 (88.9%), 18 (100%), 9 (50%) and 8 (44.4%) patients, respectively. In addition, some of the cases (88.9%) demonstrate satellite lesions. In 61.1% of cases, the hypopigmented blotches were fairly defined. About 50% of the patients in our study had linear branching vessels and faint pigment network was seen in 14 (77.8%) patients. None of the cases demonstrated perilesional hyperpigmentation or perifollicular hyperpigmentation. The hair inside these macules was of normal color.
Dermoscopy of the lesions of postinflammatory hypopigmentation showed in all cases white structureless areas with slight pinkish background, and ill-defined edge in addition to some dermoscopic findings typical of the original lesions seen in some of the patients of postinflammatory hypopigmentation following candida and psoriasis lesions.