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Disseminated Superficial Actinic Porokeratosis

BASICS

DESCRIPTION

  • A disorder of keratinization
  • Lesions of the skin with conical papules of a red and brown color surrounding the hair follicle
  • Edges may become raised over time (1).
  • Typically found in 30 to 40 year olds (2)
  • Commonly located on the arms and legs

ETIOLOGY AND PATHOPHYSIOLOGY

Proliferation of atypical keratinocytes from a mutant clonal cell line

Genetics

  • Genetic studies have reveled mutation of MVK (3).
  • Mutation of keratinocyte proliferation and differentiation (3)
  • Autosomal dominant with variable penetrance (1)

RISK FACTORS

  • UV-light exposure (2)
  • Male sex (1)
  • Immune suppression (1)
  • Infection (1)

GENERAL PREVENTION

Sunscreen and avoidance of UV exposure (2)

COMMONLY ASSOCIATED CONDITIONS

Skin malignancies in up to 10% of people (1)

DIAGNOSIS

HISTORY

  • Onset in the 30 to 40s
  • Family history of similar lesions
  • May be pruritic

PHYSICAL EXAM

  • Sun exposed areas with hyperkeratotic papules, patches, or plaques surrounded by a thin-lined elevated border
  • Palms and soles are spared.

DIFFERENTIAL DIAGNOSIS

  • Disseminated actinic keratosis
  • Actinic keratosis
  • Nevoid basal cell syndrome
  • Lichen nitidus
  • Dermal duct nevus

DIAGNOSTIC TESTS & INTERPRETATION

Initial Tests (lab, imaging)

  • Biopsy with confirmation by histology
  • Cornoid lamella in the epidermis with absent granular layer under the parakeratotic column

Follow-Up Tests & Special Considerations

Regular skin exams to monitor for malignant changes

TREATMENT

GENERAL MEASURES

No controlled studies exist as yet to evaluate treatment modality.

MEDICATION

First Line

  • Diclofenac sodium 3% topical: Apply to lesions twice daily for 60 to 90 days (4)[C].
  • This topical medication is supported by best available case study evidence as compared with other medications.

Second Line

  • 5-florouracil 5% topical: Apply to lesions twice daily for 2 to 6 weeks (4)[C].
  • Topical imiquimod 5% topical cream: Apply to defined lesions 2 times per week at bedtime for 16 weeks; and leave on skin for 8 hours (4)[C].
  • Tretinoin (50 years and younger): Apply 0.05% cream to lesions once daily at bedtime (4)[C]
  • Vitamin D3 analogs (Tacalcitol) ointment 0.0002-0.0004% once or twice a day for up to 4 weeks (4)[C]
  • Second-line treatment options are separated based on a lack of high quality evidence.

ADDITIONAL THERAPIES

Cosmetic cover-up with tinted creams or spray tans.

SURGERY/OTHER PROCEDURES

  • Photodynamic therapy (4)[C]
  • Cryotherapy (4)[C]
  • Laser therapy (4)[C]

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Yearly dermatologic examination

PATIENT EDUCATION

Avoidance of UV exposure

PROGNOSIS

Excellent

REFERENCES

11 Torkamani N, Sinclair R. Disseminated superficial actinic porokeratosis accentuated by spray tan. Int J Dermatol. 2015;54(12):e545-e546.22 Rouhani P, Fischer M, Meehan S, et al. Disseminated superficial actinic porokeratosis. Dermatology Online J.. 2012;18(12):24. http://escholarship.org/uc/item/66j9q5jh.33 Zhou MS, Xie HF, Chen ML, et al. A novel mutation for disseminated superficial actinic porokeratosis in the MVK gene. Br J Dermatol. 2014;171(2):427-429.44 Skupsky H, Skupsky J, Goldenberg G. Disseminated superficial actinic porokeratosis: a treatment review. J Dermatolog Treat. 2012;23(1):52-56.

CODES

ICD10

Q82.8 Other specified congenital malformations of skin

ICD9

692.75 Disseminated superficial actinic porokeratosis (DSAP)

SNOMED

Disseminated superficial actinic porokeratosis (disorder)

CLINICAL PEARLS

Age- and UV-related nonmalignant skin condition