“Wood-Bark Sign” in Dermoscopy of Aquagenic Syringeal Acrokeratoderma : Clinical Dermatology Review

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“Wood-Bark Sign” in Dermoscopy of Aquagenic Syringeal Acrokeratoderma

Muradia, Ishika; Patidar, Chetan Kumar

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Clinical Dermatology Review 7(1):p 110-112, Jan–Mar 2023. | DOI: 10.4103/cdr.cdr_97_21
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Aquagenic syringeal acrokeratoderma (ASA), also known as transient reactive papulotranslucent acrokeratoderma, is a rare acquired palmoplantar keratoderma that is triggered or exacerbated by brief exposure to water, commonly involving the palms, and rarely, soles can also be affected.[1-3] This condition predominantly affects adolescent and young adult women.[4] Clinical features may include translucent, flat-topped papules, which may coalesce to form plaques and hyperwrinkling postexposure to water.[3] This condition is transient because they resolve upon drying and hence is underreported.[3] “Hand-in-the-bucket sign” is a pathognomonic sign described for this condition.[5] The etiology is unknown, but aberration in the eccrine sweat gland apparatus has been suggested based on histological observations.[5]

A 16-year-old Indian male presented to the outpatient department of dermatology with a 1-year history of whitish discoloration, excessive wrinkling, and appearance of skin-colored papules over bilateral palms few minutes after immersion in water which used to resolve within ½ h. It was not associated with itching, pain, redness, or swelling. It did not hamper his daily activities but was cosmetically debilitating. Family history was negative for similar complaints, atopic diathesis, hyperhidrosis, and cystic fibrosis. Preimmersion physical examination revealed normal-appearing hands with minimal wrinkling over fingertips without any hyperlinearity [Figure 1a]. Preimmersion contact polarized dermoscopic examination using DermLite DL4 dermatoscope (3Gen, California, USA) under ×10 showed intact dermatoglyphics [Figure 2a]. The water immersion test was carried out with water at 20°C for 5 min duration. Postimmersion physical examination revealed bilaterally symmetrical hypopigmentation, thickening of palmar skin, hyperwrinkling predominantly over fingers, and accentuation of translucent, flat-topped papules of 0.1 cm size, coalescing to form ill-defined plaques, sparing the lateral margins and the dorsa of hands [Figure 1b]. Postimmersion dermoscopic examination revealed dilated sweat duct puncta and yellow globules without affecting the dermatoglyphics [Figure 2b and c]. A 4-mm punch biopsy from an affected area of his left palm was performed. Histological findings included compact orthohyperkeratosis, hypergranulosis, acanthosis, and dilated eccrine acrosynringia within the epidermis. Dermis showed numerous capillaries, eccrine glands, and grouped, crenulated, and vacuolated eccrine secretory coils [Figure 3a and b]. The patient was started on topical ammonium chloride (20%), lactic acid (6%), and urea (12%) twice daily application. The patient could not follow up due to the rising cases of COVID-19 infection.

Figure 1:
Clinical aspect of bilateral palms. (a) Preimmersion. (b) Postimmersion showing hyperwrinkled skin over fingers with flat-topped papules
Figure 2:
Polarized dermoscopic image (DermLite DL4) (×10). (a) Preimmersion showing intact dermatoglyphics. (b) Postimmersion showing deepening of dermatoglyphics with dilated sweat duct puncta (black arrow) and yellow globules (orange arrow). (c) Postimmersion showing dilated sweat duct puncta along the dermatoglyphics (red arrow) resembling a “wood’s bark” (inset)
Figure 3:
(a): Dilated eccrine acrosynringia within the epidermis (black arrow). Dermis showing numerous capillaries (red arrow), eccrine glands, and grouped eccrine secretory coils (green arrow) (H and E, ×100). (b) Dilated eccrine acrosynringia within the epidermis (black arrow) (H and E, ×200)

The history, clinical examination, dermoscopy, immersion test, and histological examination led us to the final diagnosis of ASA.

Our case is a unique case in itself as it is in an adolescent male, whereas ASA is commonly seen in adolescent and young women.[4] The pathomechanism of this condition is unclear; however, increased skin water absorption, as seen in atopic diathesis, or increased sweat salt concentration, as observed in hyperhidrosis, cystic fibrosis, or alteration in the eccrine sweat gland apparatus in accordance with the histological findings, may be implicated.[5,6] Associations have been reported with cystic fibrosis, hyperhidrosis, asthma, allergic rhinitis, urticarial, and palmar erythema.[3] The recent emergence of this condition could be attributed to the excessive increase in hand hygiene due to COVID-19 outbreak and hence increased contact with water.[7] ASA is usually asymptomatic as seen in our patient but may be associated with pain, burning, and pruritus.[3] ASA is clinically characterized by accentuated translucent to whitish papules, which may coalesce to form plaques and excessive wrinkling over palms and rarely soles.[3,6] The “hand-in-the-bucket sign” is considered as pathognomonic for ASA as it is described as patients arriving at their physician’s clinic with their hand in a bucket of water to readily demonstrate their lesions.[5] The dermoscopic findings of this condition have not been explored much. To the best of our knowledge, there are only four case reports on dermoscopy of ASA.[8-11] The defined features include dilated eccrine pores, yellow globules corresponding to widening of the excretory ducts of eccrine sweat glands, and pebbly, papular thickening at few sites termed as tripe-like structures.[8-11] Similar features were observed in our case as well. The “Wood-Bark sign” has been first described in our case which is observed as dilated sweat gland puncta seen as translucent papules arranged in concentric circles resembling the bark of a wood. This sign can be seen in patients with whorl pattern of dermatoglyphics, as seen in our patient. Histological findings exhibited by ASA include orthokeratotic hyperkeratosis, dilated acrosyringia within epidermis, hypergranulosis, and dilated dermal eccrine ducts with vacuolization, crenulated margins, pyknotic nuclei, and increased capillaries around the ducts.[3,5,6,12] The histological findings in our case were similar to those described in the literature. Most effective treatment options for ASA include topical aluminum chloride hexahydrate, salicylic acid, urea, ammonium lactate, and petroleum-based barrier agents.[5,12,13] Non-epidermolytic palmoplantar keratoderma (NEPPK): Bothnia type is a closest differential of ASA. The onset in childhood, persistent nature and presence of thick, yellow, persistent plaques with erythematous margins in NEPPK: Bothnia type differentiates it from ASA. The dermoscopy of hereditary palmoplantar keratoderma has not been explored.[14]

ASA is a clinically diagnosed entity; however, dermoscopy and histology may also aid in the diagnosis. Dermoscopy of ASA should further be explored. If the conditions permit, water immersion test should be performed in every case before making the diagnosis of ASA.

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 initial s will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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