Photodermatoses/Mucocutaneous Rxns Flashcards
Definition of Photosensitivity
abnormal response to UV radiation or visible light that underlies many skin conditions (called photodermatoses)
How is diagnosis of photosensitivity determined?
- Primarily from the history & physical exam
- Occasionally a skin biopsy
Definition of Sunburn?
Exposure to excessive UVA and UVB light, causing an inflammatory response in the skin
Clinical manifestations of Sunburn?
- painful erythema
- blistering
Timeline of Sunburn?
- Erythema at 3-5 hours following exposure
- peaks at 12-24 hours
- subsides at 72 hours
Prevention of sunburn?
- limit sun exposure during summer months b/w 10am-4pm
- protective clothing
- broad spectrum sunscreens at least 30 SPF
- Reapply sunscreen every 2 hours
- infants <6 months should avoid sun exposure
Treatment for sunburn?
- self-limiting
- may require hospitalization if severe blistering
- topical agents (aloe vera, etc)
- cool compresses
- Oral OTC analgesics
Definition of Polymorphous Light Eruption (PMLE)?
“sun poisoning” or “sun allergy” - a specific photo rash
Clinical manifestations of Polymorphous Light Eruption?
- Papulonodular lesions, symmetrically distributed on sun-exposed skin
- Pruritic
- Angular chelitis
Treatment of Polymorphous Light Eruption?
- sun protection/avoidance
- topical corticosteroids
- oral corticosteroids
- phototherapy
What is one possible cause of Polymorphous Light Eruption?
There is a genetic component to it!
Cause of Phototoxicity?
cellular damage following sun exposure when taking a precipitating compound
Examples of precipitating compounds that cause Phototoxicity?
-Tetracyclines (Doxy)
-Thiazides
- Sulfonamides
- NSAIDS
- Griseofulvin
- Tar compounds
- Phenothiazides
- St. Johns Wort
Endogenous causes of phototoxicity?
- SLE (lupus)
- Porphyria (blood disorder)
- Dermatomyositis (inflamm. disorder)
Clinical manifestations of phototoxicity?
appears as exaggerated sunburn