Acquired Speckled Acrofacial Hypomelanosis: A Novel Case Report

Abstract

Introduction

Speckled, confetti, or guttate pigmentary disorders include conditions with overlapping features and diagnostic challenges. These disorders present considerable clinical overlap with frequent diagnostic difficulties due to variable phenotypic expression.

Case Presentation

A 9-year-old Saudi female presented with a 1-year history of asymptomatic skin lesions involving the face, forearms, hands, legs, and feet. The lesions appeared spontaneously and remained unchanged since onset. Examination revealed 1–3 mm, well-defined, multiple, speckled hypopigmented-to-depigmented macules with bilateral symmetrical distribution. Wood’s lamp examination revealed no pigment accentuation. Dermoscopic examination showed well-defined, marginated hypopigmented macules with feathery margins. Microscopic examination, including special DOPA staining, revealed normal melanin pigmentation in the basal keratinocyte layer and normal to focal slightly reduced numbers of basal melanocytes, along with a focal sparse superficial perivascular mononuclear inflammatory cell infiltrate. Based on clinicopathological correlation, a diagnosis of acral speckled guttate hypomelanosis was made. The patient responded well to 1% pimecrolimus cream twice daily.

Conclusion

This case represents a novel presentation of acquired speckled acrofacial hypomelanosis with unique findings, including facial involvement and absence of hyperpigmentation. The patient's excellent response to pimecrolimus cream suggests this may be an effective treatment option for this rare condition.

Background

Speckled, confetti, or guttate pigmentary disorders are a broad category of various pigmentary disorders having considerable clinical overlap with frequent diagnostic challenges due to the variable phenotypic expression of similar genetic mutations [1]. A variety of disorders present with hypopigmented macules in guttate, speckled, or confetti patterns, and recent studies have identified instances of speckled hypopigmentation restricted to acral areas [2]. This is a rare case of speckled acrofacial hypopigmentation occurring in a pediatric patient.

Case Presentation

A 9-year-old Saudi female presented with a 1-year history of skin lesions involving the face, forearms, hands, legs, and feet. The lesions appeared spontaneously and remained unchanged in size, shape, color, or distribution since onset. The lesions were asymptomatic, with no apparent preceding or aggravating factors. The patient’s medical history was unremarkable, with no family history of similar pigmentary disorders. Examination revealed 1–3 mm, well-defined, multiple, speckled hypopigmented-to-depigmented macules with a bilateral symmetrical distribution. The macules were present over the face, forearms, hands, legs, and dorsum of the feet (Fig. 1a). Wood’s lamp examination revealed no pigment accentuation (Fig. 2). Dermoscopic examination showed well-defined, marginated hypopigmented macules with feathery margins (Fig. 3). The patient’s vitals were unremarkable, and the routine laboratory tests were all within normal limits. An initial differential diagnosis of idiopathic guttate hypomelanosis (IGH), early vitiligo, post-inflammatory hypopigmentation, and acral speckled guttate hypomelanosis was considered. With consent, a 4-mm skin punch biopsy was taken from the medial side of the right leg. The microscopic examination, including special DOPA staining, revealed normal melanin pigmentation in the basal keratinocyte layer and normal to focal slightly reduced numbers of basal melanocytes, along with a focal sparse superficial perivascular mononuclear inflammatory cell infiltrate (Fig. 4a, b). Based on clinicopathological correlation, a diagnosis of acral speckled guttate hypomelanosis was made. The patient was prescribed 1% pimecrolimus cream twice daily along with frequent emollient applications. The patient has responded very well to the treatment. The CARE Checklist has been completed by the authors for this case report and is provided as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000547928).

Fig. 1.

Multiple well-defined hypopigmented macules on the lower limb.

Fig. 2.

No accentuation under Wood’s lamp.

Fig. 3.

Well-defined, marginated hypopigmented macules with feathery margins on dermoscopy.

Fig. 4.

a Normal melanin pigmentation in basal keratinocyte layer, with normal to slightly reduced numbers of basal melanocytes (H&E, ×400). b A slightly reduced number of basal melanocytes (S100, ×400).

Discussion

Multiple dermatoses can manifest with hypopigmented macules in a guttate, speckled, or confetti distribution, including IGH, confetti hypomelanosis associated with tuberous sclerosis complex (TSC), acropigmentation of Dohi, and idiopathic confetti-like leukoderma. Among these, confetti hypomelanosis of TSC is particularly relevant in the pediatric age group, typically presenting with numerous hypopigmented macules [3–5]. The clinical presentation of this case differs from that of other reticulate acropigmentation disorders. Therefore, these related disorders will be discussed to highlight the distinguishing features of the case. To assist in differentiating between clinically similar hypopigmentary disorders, Table 1 summarizes the key distinguishing features of IGH, reticulate acropigmentation of Dohi, and acquired speckled acrofacial hypopigmentation, including findings from the current case [2, 5, 6]. IGH is rarely reported in children, usually affecting exposed areas, due to skin aging or chronic sun exposure, and the margins of the lesion are round to oval [7]. In contrast, this case occurred in a 9-year-old girl, and the margins of the lesions were feathery. A key differential diagnosis to consider is confetti hypomelanosis associated with TSC, which presents as numerous hypopigmented macules, often over the distal extremities, appearing during childhood. Unlike our patient, individuals with tuberous sclerosis commonly have other systemic features such as seizures, developmental delays, and periungual fibromas, which were not observed in this case [3, 4]. Acropigmentation of Dohi, also known as dyschromatosis symmetrica hereditaria, is another type of hereditary reticulate pigmentary disorder with ADAR1 gene mutation. Skin manifestations usually start early in life as a mixture of hypo- and hyperpigmented macules in a reticulated pattern affecting the dorsal aspect of hands and feet. Dyschromatosis symmetrica hereditaria usually occurs as an isolated disease; however, multisystemic involvement has also been reported, including acral hypertrophy, depression, psoriasis, dental anomalies, and neurological manifestations [5]. The patient had isolated skin manifestations without any additional extracutaneous features or hyperpigmentation. The hypopigmented lesions were present bilaterally and symmetrically, involving the face as well as both the upper and lower extremities. Wood’s lamp showed no accentuation, which is consistent with Aldhalaan et al. [2] case report. The clinicopathological correlation in our case revealed a decreased or normal number of melanocytes, which favored the diagnosis of speckled acrofacial hypomelanosis. A distinguishing feature in this case, compared to the previously mentioned disorders, is the facial involvement, which is very rare in speckled hypomelanosis. To the best of knowledge, only one case has been reported by Singh et al. [7] with facial involvement. Singh et al. [7] presented a 20-year-old Indian male with hypopigmented macules on the hands, feet, and face [7]. On histopathological examination, they reported an epidermis with a normal number of melanocytes and a mild increase in basal layer pigmentation [7]. The name speckled acrofacial hypomelanosis has been given to this newly acquired pigmentary disease entity [7]. Further studies are needed, including genomic analysis, to categorize this unexplained, unique, and novel entity.

Table 1.

Differential diagnosis: speckled acrofacial hypomelanosis

Feature	IGH	Reticulate acropigmentation of Dohi	Acquired speckled acrofacial hypopigmentation	Current case
Location	Sun-exposed areas (shins, forearms, shoulders)	Dorsal hands and feet	Acral areas and face (hands, feet, face)	Face, forearms, hands, legs, and dorsum of feet
Morphology	2–6-mm round-to-oval, porcelain-white macules	Mixed hypo- and hyperpigmented macules in reticulate pattern	1–3-mm speckled hypopigmented macules	1–3 mm well-defined, speckled hypopigmented-to-depigmented macules
Histopathology	Decreased melanin in basal layer, reduced melanocytes, solar elastosis	Variable melanin content, basket-weave hyperkeratosis	Normal to decreased melanocytes, focal absence of melanin, minimal inflammation	Normal melanin in basal keratinocytes, normal to focal slightly reduced melanocytes, sparse perivascular inflammation
Dermoscopy	Sharp borders, uniform white color, round-to-oval shape	Reticulate pigmented pattern, mixed pigmentation	Well-defined margins, feathery borders, speckled pattern	Well-defined marginated macules, feathery margins, no pigment accentuation
Associated features	Age >40 years, chronic sun damage, photodistribution	Early onset, hereditary (ADAR1 mutation), possible systemic features	Young to middle-aged adults, no systemic associations, facial involvement rare	Age: 9 years, no family history, no systemic features, facial involvement present

Statement of Ethics

Written informed consent was obtained from the patient’s parent for publication of this case report and any accompanying images. Ethical approval was not required for this case report in accordance with local and international guidelines.

Conflict of Interest Statement

The authors have no conflicts of interest to declare.

Funding Sources

No funding was received.

Author Contributions

Saleha Abdulrahman Aldawsari: patient management and manuscript review. Mohammed Abdullah Hussain Albaqshi and Zainab Yousef Almarzooq: manuscript writing and editing. Fatemah Abdulrahim Alhashem: literature review and figure preparation. Sarah Anwar Almulla: literature review and manuscript editing.

Funding Statement

No funding was received.

Data Availability Statement

All data generated or analyzed during this study are included in this article and its online supplementary material. Further inquiries can be directed to the corresponding author.