ISSN 2398-2950      

Dermatitis: solar

ffelis

Synonym(s): Actinic dermatitis, sunlight-induced dermatitis, ultraviolet light-induced dermatitis, photodermatitis


Introduction

  • Cause: solar-induced dermatitis in cats with light-colored areas, especially pinnae  Skin: solar dermatitis on pinna .
  • Signs: early: erythema. Later: scaling, erosions and crust formation.
  • Diagnosis: histopathology.
  • Treatment: sun avoidance, surgery, sunblock.
  • Prognosis: guarded, may progress to squamous cell carcinoma Squamous cell carcinoma  Solar: actinic - dermatitis 02 .

Pathogenesis

Etiology

  • Depigmented or lightly haired skin exposed to UVA and UVB radiation.

Specific

  • White pinnae.
  • White eyelids, planum nasale, lips and face.

Pathophysiology

  • Unclear.
  • Skin is protected from ultraviolet radiation by hair coat and melanin, so areas with sparse hair coat and light colored skin (pinnae, eyelids, planun nasale, lips, face)   →   increased risk of solar dermatitis.
  • ?Ultraviolet light   →   cell damage   →   release of chemical mediators (histamine, serotonin, kinins, prostaglandins, leukotrienes)   →   erythema.
  • ?Ultraviolet light   →   altered cell metabolism, mutation, cell death   →   changed metabolic or mitotic kinetics of surviving cells   →   epidermal hyperplasia, connective tissue damage and neoplasia.
  • ?Ultraviolet light   →   decreased numbers of epidermal Langerhans cells   →   altered local immune function.
  • These changes may contribute to the development of solar dermatitis and neoplasia.

Timecourse

  • Erythema may develop very rapidly.
  • Progression to thickened, erosive, crusting lesions and squamous cell carcinoma may take months or years   Squamous cell carcinoma: pinna 01  .
  • Lesions may wax and wane seasonally, almost resolving in winter.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Irving R A, Day R S, Eales L (1982) Porphyrin values and treatment of feline solar dermatitis. Am J Vet Res 43 (11), 2067-2069 PubMed.

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