Dermatology Online Journal

Disseminated superficial porokeratosis
Jeremy A Brauer MD, Rajni Mandal MD, Ruth Walters MD, Gary Solomon MD, Roopal V Kundu MD, Bruce E Strober MD PhD
Dermatology Online Journal 16 (11): 20

Department of Dermatology, New York University, New York, New York

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Abstract

A 62-year-old woman with psoriasis and psoriatic arthritis presented for evaluation and treatment of a one-week history of pruritic, pink spots on her trunk and extremities. Several weeks prior, therapy with certolizumab pegol and methotrexate was started for her psoriatic arthritis. A biopsy specimen was consistent with the diagnosis of porokeratosis. Owing to the setting of immunosuppression and presence of symmetric pruritic lesions on non-sun exposed areas, the diagnosis of disseminated superficial porokeratosis was made.

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History

Figure 1	Figure 2

Figure 3

A 62-year-old woman with psoriasis and psoriatic arthritis presented to the Psoriasis and Psoriatic Arthritis Clinic at the Charles C. Harris Skin and Cancer Pavilion in September, 2009, for evaluation and treatment for a one-week history of pruritic pink spots. Since her last visit six months prior, she had been hospitalized for bronchiolitis obliterans and organizing pneumonia and had discontinued infliximab and methotrexate. Once discharged, certolizumab pegol was initiated once monthly. Two months later, she was started on 10 mg of methotrexate once weekly. After three treatments of certolizumab pegol, the patient noted an acute onset of pruritic, non-tender pink spots and pustules on her left leg that rapidly progressed to involve her left thigh, right lower extremity, trunk, and arms.

At the time of presentation, she was not applying or taking any medications for her recent eruption. Aside from the certolizumab pegol and methotrexate, she denied starting additional new medications, lotions, perfumes, or detergents. She denied recent cold symptoms or illness. The patient had recently vacationed near a heavily wooded area several days before onset of the eruption. She lives alone with a dog.

In a subsequent follow up visit, six weeks after first noticing the eruption and discontinuing the certolizumab pegol, she reported improvement in the appearance of existing skin lesions, without new areas of involvement. Additionally, she admitted to having recently restarted the certolizumab pegol, despite instructions to the contrary.

Additional past medical history included hypothyroidism, depression, and hiatal hernia. She had a drug allergy to penicillin and no family history of skin disease. Further review of systems was negative.

Physical examination

On the chest, back, abdomen, buttocks, and upper and lower extremities were many 1-to-3 mm, pink, oval papules, many with collarettes of scale. A greater proportion of lesions were noted on the lower extremities.

Laboratory data

A complete blood count showed 82 percent neutrophils. C-reactive protein was elevated 19 mg/L and an erythrocyte sedimentation rate was 44 mm/hr. A comprehensive metabolic profile and an anti-streptolysin titer were normal.

Histopathology

There is focal thinning of the epidermis, with loss of the granular layer and a discrete column of parakeratosis.

Comment

Porokeratosis presents as scaly papules or plaques with a fine, elevated keratotic border. This latter clinical finding correlates histopathologically with a column of parakeratosis, which is known as the cornoid lamella, and overlies dyskeratotic keratinocytes and an absent granular layer.

Five variants of porokeratosis have been described, with disseminated superficial porokeratosis (DSP) and disseminated superficial actinic porokeratosis (DSAP) being the most common and most widespread clinically. There is a slight female preponderance [1]. The lesions appear in the third and fourth decades of life as small, asymptomatic or pruritic, 2-5 mm, pink papules. The differential diagnosis includes actinic keratoses, seborrheic keratoses, stucco keratoses, annular lichen planus, granuloma annulare, and verruca vulgaris.

Porokeratosis is largely believed to arise from an expansion of abnormal keratinocytes, but the pathogenesis is not well delineated. In this theory, the cornoid lamella correlates with the border between normal epidermis and the clone of mutant keratinocytes [2]. Additional proposed etiologic or triggering factors include genetics [3], ultraviolet light [4], trauma [5, 6], infection [7], and immunosuppression. [8, 9].

DSAP typically is observed in patients with appreciable amounts of sun exposure and on sun-exposed areas, namely the lower extremities and pruritus is noted in one-third of patients. DSP has been reported in immunocompromised patients without history of actinic damage, with bilateral symmetrical involvement of sun-exposed as well as sun-protected areas and pruritus is a common symptom [1]. Furthermore, there are reports limited to transplant recipients and those with retroviral disease [1]. There are only a few reports of drug-induced cases in the literature. [10, 11].

In one report, a 63-year-old man, who received perioperative antibiotics and subsequent anticoagulation therapy for a pulmonary embolism, developed multiple, thin, annular, erythematous, keratotic plaques with double-edged borders on the anterior aspects of the lower extremities. Specifically, perioperatively he had received intravenous flucloxacillin, gentamicin, unfractionated and low-molecular-weight heparin, tazocin, and aspirin. A biopsy specimen showed the histopathologic findings of porokeratosis [10]. After five weeks off all the medications and with only a few days treatment with topical mometasone, the lesions had almost completely resolved and he remained asymptomatic. A second report involved a patient with metastatic prostate cancer who was enrolled in a trial with suramin. Ten days after the initiation of therapy, he developed an erythematous, annular eruption with keratotic scale peripherally. The lesions were predominantly over the legs, and the diagnosis was confirmed by histopathologic examination [11].

Treatment options include cryotherapy [12], topical 5-fluorouracil [13], topical retinoids, oral acitretin [14], CO2 laser [15], and surgical excision [15].

To the best of our knowledge at the time of this report, this is the first description of a patient on anti-tumor necrosis factor therapy who developed disseminated superficial porokeratosis. With the continued use of these and other immunomodulating agents this entity may become more prevalent.

References

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5. Nova M, et al. Porokeratosis arising in a burn scar. J Am Acad Dermatol 1991; 25:354 [PubMed]

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10. Goulding JMR, et al. Eruptive disseminated superficial porokeratosis with rapid resolution: a drug-induced phenomenon? Clin Exp Dermatol 2009; epub;1-3 [PubMed]

11. O’Donnell BP, et al. Suramin-induced skin reactions. Arch Dermatol 1992; 128: 75 [PubMed]

12. Shumack SP, Commens CA. Disseminated superficial actinic porokeratosis: a clinical study. J Am Acad Dermatol 1989; 20:1015 [PubMed]

13. McDonald SG, Peterka ES. Porokeratosis (Mibelli): treatment with topical 5-fluoruracil. J Am Acad Dermatol 1983; 8:107 [PubMed]

14. Goldman GD, Milstone LM. Generalized lineaer porokeratosis treated with etretinate. Arch Dermatol 1995; 131:496 [PubMed]

15. Rabbin PE, Baldwin HE. Treatment of porokeratosis of Mibelli with CO2 laser vaporization versus surgical excision with split-thickness skin graft: a comparison. J Derm Surg Oncol 1993; 19:199 [PubMed]

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