Dermoscopic Features of Acquired Brachial Cutaneous Dyschromatosis (ABCD): A New Evolving Investigative Tool

Sir,

Acquired Brachial Cutaneous Dyschromatosis (ABCD) is a pigmentary disorder predominantly found in menopausal age group women, characterized by asymptomatic well-demarcated surrounding skin with irregular areas of hyperpigmentation and intermingled hypopigmentation, bilaterally over the dorsal aspect of forearm and arm. Histologically, it shows atrophy of epidermis, solar elastosis, and homogenous hyperpigmentation in the basal layer with no pigmentary incontinence, and somewhere superficial telangiectasia.[1,2] The most commonly reported skin type is Fitzpatrick type III–IV.[1]

A 47-year-old labourer woman of Fitzpatrick skin type III presented to the skin OPD with asymptomatic well-demarcated brown patches with intermingled hypopigmented macules in a geographic pattern, and atrophy at some places over the dorsal aspect of both arm and forearm for 10–15 years [Figure 1a]. There was a history of chronic sun exposure. Her face and dorsum of hands were spared. There was no history of taking antihypertensive drug. The systemic examination was found normal.

Figure 1.

(a and b) Well-demarcated areas of hyperpigmentation with dispersed hypopigmented lesions on dorsum of arms and forearms

Similarly, a 51-year-old female came to the skin OPD complaining of irregular mixed hyper and hypopigmented areas over the dorsal aspect of both forearm and arm [Figure 1b]. She had been noticing it for 10 years. She was on treatment for hypertension and diabeties for 20 years. Her Fitzpatrick skin type was type IV. Physical and systemic examinations were normal.

Our differential diagnoses were melasma, exogenous ochronosis, and lichen planus pigmentosus (LPP). Lesional skin biopsy was done. Histopathology showed atrophy of the epidermis with marked hyperpigmentation in the basal layer. The upper dermis showed elastosis and telangiectatic blood vessels. (H and E stain, 4×, 10×, 40×) [Figure 2a-c].

Figure 2.

(a-c) Skin biopsy showed atrophy of the epidermis with marked hyperpigmentation in the basal layer. The upper dermis showed elastosis and telangiectatic blood vessels. [H and E stain, 4× (a), 10× (b), 40× (c)]

To aid in diagnosis, we performed dermoscopy in both the cases. It showed irregularly arranged grayish-brown dots and globules (density of melanophages) (red arrow), interspersed white areas (atrophy), exaggerated skin markings in a net-like pattern (orange arrow), yellowish hue in-between areas (eccrine duct obliteration) (green square), perifollicular atrophic areas (purple arrow), and telangiectasia (black arrow) (Dermlite 3, 10×, polarized) [Figure 3].

Figure 3.

Dermoscopy showed irregularly arranged grayish-brown dots and globules (red arrow), interspersed white areas, exaggerated ski markings in a net-like pattern (orange arrow), yellowish hue in-between areas (green square), perfollicular atrophic areas (purple arrow), telangiectasis (black arrow). (Dermlite 3, 10×, polarized)

Although very few case reports of ABCD have been published in English literature, we used dermoscopy, which is a new evolving tool to aid in diagnosis.

The study done by Rongioletti and Rebora on the large cohort showed an association of this hyperpigmentation with antihypertensive drugs especially ACE inhibitors, according to their result.[1] Hu et al.[2] later gave the possible association of ABCD with chronic sun exposure where our case 1 fits in.

To differentiate, melasma presents with hyperpigmented patches exclusively over the centrofacial region, malar, mandible, rarely over the upper chest, and extremities with dermoscopic areas of hyperpigmentation in pseudo rete ridges in the skin, and histopathologic findings same as ABCD but without epidermal atrophy and telangiectasia.[3]

LPP shows up as diffuse hyperpigmentation over the temple, neck, flexural areas with histologic findings,[4] whereas erythema dyschromicum perstans is characterized by asymptomatic grayish macule and patches with erythematous plaques over the trunk and proximal extremities.[4] Dermoscopic findings of differential diagnoses are tabulated [Table 1]. The treatment options are not well-defined and challenging to the dermatologists due to association with prolonged sun exposure. But treatment options like avoiding chronic sunbath, utilizing sunscreens and other depigmenting agents like hydroquinone, azelaic acid, chemical peeling, surgically by Q-switched laser, pigment specific lasers, or resurfacing lasers can be useful.[5]

Table 1.

Dermoscopic findings of differential diagnoses

Differential diagnosis	Dermoscopic findings
Melasma	Light to brown color background with brown granules and globules with sparing follicles and sweat glands and pseudoreticular network
Lichen planus pigmentosus	Dots and globules in different hue like brown, black, grayish-brown in different patterns such as hem-like, arcuate, reticular
Exogenous ochronosis	Dark-brown globules, elongated, curvilinear worm-like structures conjoined together in reticulated pattern
Our cases	Irregularly arranged grayish-brown dots and globules, interspersed white areas, exaggerated in skin markings in net-like pattern, yellowish hue in-between areas, obliterated sweat gland openings, perifollicular atrophic areas

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Conflicts of interest

There are no conflicts of interest.