|Year : 2020 | Volume
| Issue : 3 | Page : 182-183
Symmetrical acrokeratoderma: A distinct disease entity from acral acanthosis nigricans?
Xia Liu, Yan-Ning Xue, Cheng Tan
Department of Dermatology, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
|Date of Submission||18-Mar-2018|
|Date of Decision||23-Oct-2018|
|Date of Acceptance||19-Nov-2018|
|Date of Web Publication||10-Sep-2020|
Dr. Cheng Tan
Department of Dermatology, Affiliated Hospital of Nanjing University of Chinese Medicine, 155 Hanzhong Road, Nanjing 210029
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Liu X, Xue YN, Tan C. Symmetrical acrokeratoderma: A distinct disease entity from acral acanthosis nigricans?. Dermatol Sin 2020;38:182-3
A 38-year-old Chinese male complained of having hyperpigmented keratotic patches on the wrist and dorsal surface of the hands for 2 years. The lesions initially developed on the wrist without itching in May 2015, and gradually spread to the dorsum of both hands over the past year. He noticed that the lesions became partially white several minutes after contact with water or after perspiring. Symptoms were exacerbated in hot, humid weather. There was neither itching nor other abnormal sensations. He had no allergies and had no contributing medical history. He acknowledged ineffective response of the eruptions with the intermittent topical application of corticosteroids. An examination of the skin revealed multiple well-defined hyperkeratotic patches that were distributed symmetrically on the wrists and part of the dorsal surface of the hands. The palms and soles were completely unaffected. The lesions were black, brown, or gray in color [Figure 1]a, but quickly took on white, macerated appearances on contact with water [Figure 1]b and [Figure 1]c. The lesion returned to its original presentation after drying. Skin histopathology revealed hyperkeratosis and hypergranulosis in the epidermis [Figure 2]. These clinical and pathological features were consistent with symmetrical acrokeratoderma (SAK). The patient was informed of the benign nature of the disorder, and the lesion was alleviated as expected at the following up in winter.
|Figure 1: Well-defined hyperkeratotic patches distributed symmetrically on the wrists and part of the dorsal surface of the hands. The lesions were black, brown or gray in color. (a) Presentation of the lesion on the dorsal surface of the hand before. (b) And 2 min after. (c) Exposure to water|
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|Figure 2: There was hyperkeratosis, acanthosis, and hyperpigmentation in the epidermis, with a sparse infiltration of lymphocytes around the capillaries (H and E, ×100)|
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SAK, or acquired SAK, was proposed to be a distinct skin disorder in China in 2008. A literature review produced several cases with similar presentations that had been reported as an acral acanthotic anomaly or as Acral acanthosis nigricans. The condition predominantly affected the patients of Chinese and Indian descent without gender predilection. Although SAK is most prevalent during adulthood, the earliest reported occurrence was in a 2-year-old patient.
The hallmark presentation of SAK is well-circumscribed hyperkeratotic patches of various shades and colors, varying from dark brown-to-black. Patches are usually symmetrically distributed on the wrists and the dorsal surface of the hands, although they also occasionally occur on the feet, elbows, knees, and face. However, the palms and the soles are both spared. Lesions in SAK may last from months-to-years, with or without mild itching. SAK is aggravated in summer and is ameliorated in winter. The lesions macerate to a white color several minutes after immersing the hands in water or after sweating and spontaneously restores its original appearance after drying., A higher incidence of SAK is likely to occur among individuals with ichthyosis vulgaris, atopic dermatitis, asthma, inflammatory bowel disease, and hyperhidrosis. SAK shows marked hyperkeratosis, acanthosis, and hyperpigmentation of the epidermis. There is usually a sparse infiltration of lymphocytes around the capillaries in the superficial dermis. Under electron microscopy, keratinocytes in SAK exhibit partial desmosomal splitting and clumps of keratin tonofilaments are present. SAK has a distinct immunohistochemical profile characterized by the overexpression of filaggrin, involucrin, K14, K16, Ki-67, and Melan-A, which may be associated with the abnormal keratinization and pigmentation in SAK.
The cause of SAK remains elusive. Several factors may contribute to the development of SAK, including impaired epidermal barrier function, chemical exposures, and humid climates. Malassezia infection is invariably found in SAK. Further investigations are required to elucidate the exact pathogenesis of this enigmatic dermatosis.
Acral lesions in SAK clinically resemble Acral acanthosis nigricans, aquagenic acrokeratoderma, pigmentary changes in Addison's disease, friction melanosis, etc. Clinically, Acral acanthosis nigricans typically presents with velvety, hyperpigmented plaques over protruding areas such as knuckles, elbows, and knees, with no alteration of this condition on exposure to water. The histopathology of Acral acanthosis nigricans is characterized by obvious papillomatosis and intervening “valleys.” All of these features make it distinct from the lesions on our patient. Although lesions in aquagenic acrokeratoderma also appear on the palms after the exposure to water, the transient translucent papules, the absence of hyperpigmentation, and the preferential site of involvement distinguish it from SAK. Pigmentation in Addison's disease is diffuse, and the lack of hyperkeratosis and other systemic abnormalities help differentiate it from other conditions. The hyperpigmentation in friction melanosis is only found in sites exposed to repetitive friction, which is absent in SAK.
Most cases of SAK spontaneously improve with no urgent need for the treatment. To patients who experience embarrassment about the dirty appearance of the condition, retinoids, topical corticosteroids, and keratolytic agents can be recommended to relieve symptoms. Nonpharmacologic treatments are also beneficial, including avoiding submergence the affected area in water, reducing sweating, avoiding humid environments, and using emollients daily.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published, and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
The study was financially supported in part by the 333 High-Level Personnel Training Project of Jiangsu Province.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]