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Table of Contents
Year : 2020  |  Volume : 38  |  Issue : 4  |  Page : 221-224

Disseminated superficial porokeratosis and disseminated superficial actinic porokeratosis: A case series of 39 patients

1 Department of Dermatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University; Department of Family Medicine, Chi Mei Medical Center, Yongkang, Tainan, Taiwan
2 Department of Dermatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan; Department of Dermatology, Kaohsiung Veterans General Hospital Tainan Branch, Kaohsiung, Taiwan
3 Department of Dermatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University; International Center for Wound Repair and Regeneration, National Cheng Kung University, Tainan, Taiwan
4 Department of Dermatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan

Date of Submission12-May-2020
Date of Decision07-Aug-2020
Date of Acceptance16-Aug-2020
Date of Web Publication16-Dec-2020

Correspondence Address:
Dr. Chao-Chun Yang
Department of Dermatology, National Cheng Kung University Hospital, No. 138 Sheng-Li Rd., Tainan 704
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ds.ds_41_20

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Porokeratosis is characterized by keratotic papules or plaques with a ridge-like border. Both disseminated superficial porokeratosis (DSP) and disseminated superficial actinic porokeratosis (DSAP) manifest as numerous, small, round maculopapules with thin thread-like elevated border but differ in their distribution of lesions and the association with sunlight exposure. To analyze and compare the clinical features of DSP and DSAP, we conducted this hospital-based retrospective study. A total of 39 patients were recruited, including 19 DSP patients and 20 DSAP patients. The median age of diagnosis of DSP and DSAP patients was 63 years and 59 years, respectively. A male predominance was noted in DSP, while a female predominance was noted in DSAP. Itchiness was the most common symptom in both subtypes. Commonly used treatments included corticosteroids and retinoids, both topical and oral. Among the treatments, oral retinoid, diclofenac gel, and cryotherapy showed higher rates of improvement, but none of them yielded complete remission of the skin lesions. In conclusion, DSP and DSAP showed differences in the gender predilection, and both DSP and DSAP had prolonged clinical course and generally refractory to topical or systemic treatments.

Keywords: Clinical manifestation, disseminated superficial actinic poro keratosis, disseminated superficial keratosis, Porokeratosis, treatment outcome

How to cite this article:
Hsueh YT, Hsu TC, Hsu CK, Lee JY, Yang CC. Disseminated superficial porokeratosis and disseminated superficial actinic porokeratosis: A case series of 39 patients. Dermatol Sin 2020;38:221-4

How to cite this URL:
Hsueh YT, Hsu TC, Hsu CK, Lee JY, Yang CC. Disseminated superficial porokeratosis and disseminated superficial actinic porokeratosis: A case series of 39 patients. Dermatol Sin [serial online] 2020 [cited 2022 Dec 3];38:221-4. Available from: https://www.dermsinica.org/text.asp?2020/38/4/221/303703

  Introduction Top

The classic type of porokeratosis is featured as a keratotic plaque with a thread-like scale at the lesional border, which corresponds to a histopathological hallmark called cornoid lamella. Among the subtypes of porokeratosis, disseminated superficial actinic porokeratosis (DSAP) is the most common form.[1] Although DSAP and disseminated superficial porokeratosis (DSP) share common features as disseminated papular keratotic lesions, the two are regarded as different entities. DSP was introduced in 1937, and though the exact pathogenesis remains unclear, proposed pathogenic and associated factors include immunosuppression and transplantation,[2] malignancy,[3] liver diseases,[4] and diabetes mellitus.[5] On the other hand, DSAP was introduced by Chernosky in 1967,[6] pertaining only to lesions with distribution over sunlight-exposed body areas. DSAP was believed to have direct association with sunlight and/or artificial light exposure and was later proven by an experimental induction study.[7] Due to the clinical similarity of the two, it is sometimes difficult to clearly distinguish DSP and DSAP. Therefore, we conduct this study to analyze the features of DSP and DSAP and to find the difference between the two.

  Patients And Methods Top

In this hospital-based study, patients between 1989 and 2018 were retrospectively reviewed from the database of the Department of Dermatology, National Cheng Kung University Hospital. Patients with clinical features of disseminated, small, keratotic papules and histopathology-confirmed diagnosis of porokeratosis were included in this study, and their medical records and clinical photographs were reviewed and analyzed; those patients with one solitary lesion, linear distribution, or limited focal distribution of skin lesions were excluded. The distinction between DSP and DSAP was based on the distribution of lesions. DSAP was defined as either lesion distribution limited to the sunlight-exposed body areas, including face, neck, upper trunk, arms, and legs, or possessing definite history of exacerbation by sunlight exposure. On the other hand, DSP was defined as lesions involving areas without exposure to sunlight, including the lower trunk, buttock, pubic, and genital areas, and no prior history of exacerbation by sunlight exposure.

Clinical information for analysis included age of diagnosis, gender, personal medical history, family history of DSP/DSAP, lesion distribution, clinical symptoms, history of exacerbation by sunlight exposure, and treatment outcomes. The age of diagnosis was defined as the age when the patient first visited our clinic for DSP/DSAP. For treatment outcome, lesion improvement was defined as either decreased number of lesions, relief of symptoms, or alleviation of inflammatory status. Medication or treatment prescribed for at least 2 weeks before clinical response was considered contributory to improvement. Follow-up of the patient was conducted either at the clinic or via telephone interview. The Institutional Review Board of National Cheng Kung University Hospital approved this retrospective study and waived the patient informed consent requirement (IRB Number: B-ER-109-080).

  Results Top

Clinical characteristics

Of the 39 patients included in our study, 19 were DSP and 20 were DSAP patients. The age of diagnosis was 38–83 years (median, 63 years) for DSP patients and 39–79 years (median 59 years) for DSAP patients. The DSP group showed a male predominance (12 males and 7 females), while a female predominance was noted in the DSAP group (7 males and 13 females) [Table 1]. Among the 29 patients with available medical records pertaining to their clinical symptoms, 24 patients experienced itchiness (82.7%), 4 patients suffered from itchiness with pain (13.8%), and 1 patient was asymptomatic (3.4%). There was no difference between the DSP and DSAP groups regarding the clinical symptoms. Among the 15 patients with available family history, 3 patients (20%) had positive family history of DSP/DSAP, consisting of a father and his daughter in the DSAP group, and one female patient in the DSP group, who reported that her father had similar lesions on his limbs. Four DSAP patients reported a definite history of sunlight-induced exacerbation. Regarding the distribution of skin lesions, lower extremities were the most commonly affected body area in both the DSP and DSAP groups (89% and 100%, respectively), followed by upper extremities (84% and 50%, respectively) [Table 1].
Table 1: Patients' characteristics and clinical presentation

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Associated systemic conditions

The history of concomitant diseases relevant to DSP and/or DSAP was collected, including immunosuppression, autoimmune disease, malignancy, liver disease, metabolic disorder, and previous phototherapy [Table 2]. Neither group had immunosuppression, and none underwent phototherapy before or upon porokeratosis onset.
Table 2: Summary of the diseases associated with disseminated superficial porokeratosis and disseminated superficial actinic poro keratosis

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Treatment and follow-up

The most commonly used topical treatment was corticosteroid (71.7%), followed by retinoid (41%), diclofenac gel (15.3%), 5-fluorouracil (12.8%), Vitamin D3 and its derivatives (10.3%), imiquimod (7.7%), and tacrolimus (2.5%). Systemic agents include oral retinoid (20.5%), oral corticosteroid (12.8%), and oral methotrexate (2.5%). Therapeutic procedures consist of cryotherapy (12.8%), excimer laser (5.1%), erbium: yttrium-aluminum-garnet laser (5.1%), carbon dioxide laser (2.5%), photodynamic therapy (2.5%), and radiotherapy (2.5%). The therapeutic effects could not be assessed accurately due to incomplete medical chart recording. Among all treatments mentioned above, oral retinoid showed the highest rate of improvement. For systemic agents, treatment with acitretin reported improvement in 5/7 patients (71.4%), while both patients prescribed with isotretinoin reported improvement (100%). The effective dose of acitretin was 0.2–0.4 mg/kg/day, and improvement was noted at the 4th–6th week of treatment. The effective dose of isotretinoin was also 0.2–0.4 mg/kg/day, and improvement was noted at the 2th–7th week of treatment. For other treatments, diclofenac gel (66.7%) and cryotherapy (60%) also had higher improvement rates than the other treatments.

Long-term prognosis

Of the 4 patients who had regularly followed up at our outpatient department for more than 2 years, all of them showed persistent lesions or lesion progression. One female patient (61 years old, DSP group) received multiple treatments including calcipotriol, imiquimod, excimer laser, topical and oral corticosteroid, and retinoid. Although the use of the excimer laser resulted in partial resolution of her primary lesion, recurrence occurred 1 year later. In another female patient (56 years old, DSAP group) who received calcipotriol, topical retinoid, 5-FU, salicylic acid, and topical and oral corticosteroid, ulcerative change at lesion site was found after application of 5-FU, with subsequent incomplete lesion disappearance. Although most patients reported unsatisfactory response to treatment, 2 cases reported self-resolution of their disease after several years through telephone interview.

  Discussion Top

Our study showed a male predominance in the DSP group but a female predominance in the DSAP group; the findings are in line with a previous case series.[8] On the other hand, our series showed a much later onset age in both the groups, compared to the literature.[1] Although DSP can occur in children, none of our patients had disease onset in childhood. In DSAP, the onset age was reported to be 20–40 years,[1] but our series had a range of onset age of 20–79 years. A study from China also reported older onset age in DSP and DSAP patients,[8] as in ours. Itch was the most common symptom for DSP and DSAP in our series, as in the literature.

Inheritance is an important factor in DSAP, supported by a previous case series reporting 66.7% of DSAP patients to be inherited.[8] Recently, several genetic mutations in the mevalonate pathway-related genes, including MVK, MVD, PMVK, and FDPS, were detected in patients with DSAP and DSP.[9] The current concept regards porokeratosis as an autoinflammatory keratinization disorder, and malfunctions in the mevalonate pathway may lead to abnormal differentiation of keratinocytes and autoinflammation.[9] However, in these studies, DSP and DSAP patients were not analyzed separately. Further study to compare the genetic basis of DSP and DSAP is required to better define the two subtypes.

Despite DSP and DSAP bearing similar clinical features, their contributing factors are believed to be different. While DSAP is caused by sunlight exposure, DSP has a possible relation to several systemic conditions, including immunosuppression, malignancy, and diabetes.[2],[5] In our study, none of our patients were in immunosuppressive status or underwent organ transplantation.

There is no standard treatment of DSP and DSAP, and to date, no controlled trial has been published. Topical steroid is mostly used for symptomatic relief during the inflammatory stage. Retinoid, topical diclofenac gel, cryotherapy, phototherapy, and various laser treatments have also shown beneficial clinical responses.[10] However, complete resolution of lesions was seldom reported, and the long-term prognosis of DSP and DSAP was still unknown in the literature. Treatments which had effects lasting for longer than 1 year without recurrence included topical tacalcitol, systemic acitretin, Er-YAG laser, CO2 laser, and MAL-photodynamic therapy.[10] Progression to Bowen's disease and squamous cell carcinoma was reported in one DSP and two DSAP patients, with a mean period of 3.6 years between the diagnosis of porokeratosis and malignancy.[11] In our study, there was no evidence of malignant transformation of the lesions in both the groups.

  Conclusion Top

Except sex predominance, our patients of DSP and DSAP did not show significant differences between their clinical features. Treatment of DSP and DSAP remains difficult, and the long-term prognosis was not favorable. Further genetic studies may help to clarify the pathogenesis of DSP and DSAP and look for new therapeutic strategies.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Kanitakis J. Porokeratoses: An update of clinical, aetiopathogenic and therapeutic features. Eur J Dermatol 2014;24:533-44.  Back to cited text no. 1
Bencini P, Tarantino A, Grimalt R, Ponticellp C, Caputo R. Porokeratosis and immunosuppression. Br J Dermatol 1995;132:74-8.  Back to cited text no. 2
Takata M, Shirasaki F, Nakatani T, Takehara K. Hereditary non-polyposis colorectal cancer associated with disseminated superficial porokeratosis. Microsatellite instability in skin tumours. Br J Dermatol 2000;143:851-5.  Back to cited text no. 3
Park BS, Moon SE, Kim JA. Disseminated superficial porokeratosis in a patient with chronic liver disease. J Dermatol 1997;24:485-7.  Back to cited text no. 4
Nakamura M, Fukamachi S, Tokura Y. Acute onset disseminated superficial porokeratosis associated with exacerbation of diabetes mellitus due to development of anti-insulin antibodies. Dermatoendocrinol 2010;2:17-8.  Back to cited text no. 5
Chernosky ME, Freeman RG. Disseminated superficial actinic porokeratosis (DSAP). Arch Dermatol 1967;96:611-24.  Back to cited text no. 6
Neumann RA, Knobler RM, Jurecka W, Gebhart W. Disseminated superficial actinic porokeratosis: Experimental induction and exacerbation of skin lesions. J Am Acad Dermatol 1989;21:1182-8.  Back to cited text no. 7
Gu CY, Zhang CF, Chen LJ, Xiang LH, Zheng ZZ. Clinical analysis and etiology of porokeratosis. Exp Ther Med 2014;8:737-41.  Back to cited text no. 8
Akiyama M. Autoinflammatory keratinization diseases (AiKDs): Expansion of disorders to be included. Front Immunol 2020;11:280.  Back to cited text no. 9
Weidner T, Illing T, Miguel D, Elsner P. Treatment of Porokeratosis: A Systematic Review. Am J Clin Dermatol 2017;18:435-49.  Back to cited text no. 10
Tan LS, Chong WS. Porokeratosis in Singapore: An Asian perspective. Australas J Dermatol 2012;53:e40-4.  Back to cited text no. 11


  [Table 1], [Table 2]


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