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Skin: solar dermatitis
Synonym(s): Actinic dermatosis
Introduction
- Solar dermatitis is a phototoxic reaction that occurs in poorly pigmented skin.
Presenting signs
- It can affect the nose or the trunk and extremities.
- The nasal forms presents with erythema Skin: erythema multiforme and scaling that progresses into crusting and ulcerations.
- The form occurring on the body presents with comedones, erythema that progresses into ulcerations and crusting.
- The course is chronic with progressive worsening with repeated exposure to sunlight.
Geographic incidence
- Frequent in sunny climates.
Age predisposition
- It can start at any age depending on sun exposure.
Breed/Species predisposition
- Australian Shepherds Australian Shepherd are at increased risk for nasal solar dermatitis.
- Mexican hairless dogs Mexican Hairless , Dalmatians Dalmatian , American Staffordshire terriers American Staffordshire Terrier , white boxers Boxer and White Bull Terriers Bull Terrier are at risk for the dermatitis affecting the trunk and extremities.
Cost considerations
- Therapy with retinoids is expensive.
- If squamous cell carcinoma develops, surgery for removal of lesions is recommended, which would add to the cost of therapy.
Special risks
- Development of squamous cells carcinoma and hemangioma and hemangiosarcoma.
Pathogenesis
Etiology
- Caused by UV exposure.
Predisposing factors
General- Lack of pigmentation.
- Lack of hair.
- Sunbathing.
- Some breeds are at increased risk for lack of pigmentation.
Specific
- Sunny climates.
Pathophysiology
- Sun induced damage of the skin.
- UV light triggers keratinocyte apoptosis and leukocyte infiltration.
- Follicular damage occurs leading to dilation and recruitment of leukocytes in the areas.
- Dysplastic and neoplastic changes occur with time.
Timecourse
- Acute: erythematous painful lesions.
- Chronic: to develop elastin changes and dysplastic modifications.
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.
- Ishii Y, Kimura T, Itagaki S, Doi K (1997) The skin injury induced by high energy dose of ultraviolet in hairless descendants of Mexican hairless dogs. Histol Histopathol 12 (2), 383-389 PubMed.
- Frank L A, Calderwood-Mays M B, Kunkle G A (1996) Distribution and appearance of elastic fibers in the dermis of clinically normal dogs and dogs with solar dermatitis and other dermatoses. Am J Vet Res 57 (2), 178-181 PubMed.
- Breen P T (1972) Nasal solar dermatitis. Vet Med Small Anim Clin 67 (6), 652-653 PubMed.
- Yankell S L, Khemani L, Dolan M M (1970) Sunscreen recovery studies in the Mexican hairless dog. J Invest Dermatol 55 (1), 31-33 PubMed.