Photodermatology Flashcards
What is the definition on photobiology?
the study of non ionising radiation on living systems
Name 4 common abnormal cutaneous photosensitivity reactions?
Polymorphic light eruption (PLE) i.e. prickly heat
Chronic Actine Dermatits (CAD)
Hartnup’s disease
Drug enduced photosensitivity
What is normal cutaneous photosensitivty?
Sunburn
What is porphyrias?
The porphyrias are a group of rare diseases in which chemical substances called porphyrins accumulate with high metabolism. The body requires porphyrins to produce heme, which carries oxygen in the blood
What are 4 main types of porphyrias?
Phototoxic skin porphyrias
Bilstering and skin porphyrias
Acute attack porphyrias
Severe congenital porphyrias
Give an example of severe congenital porphyrias?
Congenital Erythropeotic Porphyria
What is the most common type of porphyria?
Porphyria cutanea tarda (PCT)
Signs of Congenital Erythropeotic Porphyria
Extreme sensitivity to sun light Disfiguring scars Dystrophy of nails Blindness due to lenticular scarring Brownish discolouration of teeth
Signs of PCT?
Bullous blistering on hands Milia spots Hyperpigmentation Hypertrichosis Solar uticaria (opening of blood vessels in dermis) Morphea (scarring process in dermis)
What do diagnose PCT?
Woods lamp - detects uroporphyrinogen in the urine
What could the underlying cause of PCT?
Alcohol
Viral hepatisis (hep c)
Oestrogens
Heamochromotosis
What causes Erythroietic Protoporphyria?
Deficiency in the enzyme ferrochelatase, leading to abnormally high levels of protoporphyrin in the tissue
If a patient presents with a history of immense itch and pain due to little sunlight and histamine etc does not relieve the pain, what disease should be considered?
Erythroietic Protoporphyria
What are the 3 rays produced by the sun?
UVC
UVB
UVA
Which sun rays penetrate the atmosphere and the skin?
UVB
UVA
