Dermoscopy of Acrodermatitis Continua of Hallopeau.

Abstract

A 29-year-old female presented with recurrent episodes of painful pustules over the right thumb for the past 8 months. She was treated with oral antibiotics along with avulsion of the nail plate, but it did not improve her condition. She had no history of other skin disorders. On examination, the nail plate was absent. Erythematous plaque with scaling and few areas of crusting were present involving the nail bed and pulp of the right thumb [Figure 1a] along with a single pustule on the right thumb [Figure 1b]. Dermoscopy (Polarized contact light dermoscopy; Dermlite DL4; 10×) revealed yellowish-white scales and linear blood vessels over the nail bed along with few hemorrhagic spots [Figure 2a]. Additionally, yellow globules were seen on the lateral nail fold and dotted vessels arranged in a regular pattern were seen over the pulp area [Figure 2b]. A Gram stain was done from the pustule, which was sterile and showed only neutrophils. A diagnosis of acrodermatitis continua of Hallopeau (ACH) was made based on the clinical and dermoscopic correlation. She was treated with oral cyclosporine and topical calcipotriol with good improvement in 2 weeks [Figure 3a and b].Figure 1: (a) The nail plate is absent. Erythematous plaque with scaling and few areas of crusting is seen involving the nail bed and pulp of the right thumb. (b) A single pustule is seen on the right thumbFigure 2: (a) Dermoscopic image showing yellowish-white scales (black arrow) and linear blood vessels over the nail bed (blue arrow) along with few hemorrhagic spots (red arrow). (b) Dermoscopic image showing dotted vessels arranged in a regular pattern (yellow arrows) over the pulp area. (Polarized contact light dermoscopy; Dermlite DL4; 10×)Figure 3: Clinical (a) and dermoscopic (b) images showing near-complete resolution of the lesions after 2 weeks. (Polarized contact light dermoscopy; Dermlite DL4; 10X)ACH, a variant of pustular psoriasis, is a rare, sterile pustular eruption of the distal fingers and/or toes. It is a chronic and progressive condition and can lead to irreversible complications including onychodystrophy and osteitis, which may result in anonychia and distal phalanx osteolysis, respectively; hence, an early and prompt diagnosis is required.[1] Dermoscopy of pustular psoriasis reveals yellow globules and regularly distributed dotted vessels which on histology correspond to nonfollicular superficial pustules and dilated vessels in homogenously elongated dermal papillae, respectively.[2] E. Errichetti et al. described dermoscopic findings in two cases of ACH which showed whitish-yellowish hyperkeratosis/scaling along with single or multiple pustules, dotted and linear vessels, and hemorrhagic spots.[3] These findings aid in differentiating ACH from other localized conditions such as onychomycosis, nail lichen planus, acral hand eczema, and psoriatic onychopathy.[3] We report our case to highlight the dermoscopic features of ACH which can help in the preliminary evaluation, thus reducing the diagnostic delay. As biopsy over the distal digits is often distressing and difficult, dermoscopy can be considered a valuable tool in such cases. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.