Photodermatology

Question 1

what is photobiology?

Answer 1

the study of non-ionising radiation on living systems

Question 2

what are the two types of normal cutaneous photosensitivity?

Answer 2

fitzpatrick sun-reactive skin prototypes IV (sometimes V & VI added)

Question 3

what do fitzpatrick sun-reactive skin photoypes depend on?

Answer 3

depends on the amount of melanin pigment in the skin

Question 4

how are fitzpatrick sun-reactive skin prototypes determined?

Answer 4

determined by constitutional color (white, brown or black skin) and the result of exposure to ultraviolet radiation (tanning)

Question 5

what do the fitzpatrick sun-reactive skin prototypes range from?

Answer 5

Always burning, never tan; sensitive to exposure; redheaded, freckles (1) to rarely burns, least sensitive to sun; deeply pigmented skin (6)

Question 6

what are the main groups of porphyrias?

Answer 6

• phytotoxic skin porphyries
• blistering & fragility skin porphyrias
• acute attack porphyria
• severe congenitl porphyrias

Question 7

what are porphyrias?

Answer 7

a group of rare diseases in which chemical substances called porphyrins accumulate which manifests as either neurological complications or skin problems or occasionally both.

Question 8

what are the treatment options for phototoxicity?

Answer 8

behavioural avoidance
clothing 
sunscreen use 
hardening (PUVA)
chromophore removal 
inhibition of mediator/action release 
inhibition of inflammatory response

Question 9

what is the typical presentation of Porphyria cutanea tarda (PCT) Type I?

Answer 9

blisters & fragility 
hyperpigmentation 
hypertrichosis 
solar urticaria 
morphoea

Question 10

what are the usual causes of porphyria cuteness tarda?

Answer 10

alcohol
viral hepatitis
oestrogens
haemochromatosis

Question 11

what is erythropoietic protoporphyria?

Answer 11

build up of protoporphyrin in the blood, especially in the red blood cells leading to light sensitivity

Question 12

how does erythropoietic protoporphyria usually present?

Answer 12

hypersensitivity of the skin to sunlight and some types of artificial light, such as fluorescent lights
after exposure to light, the skin may become itchy and red, maybe a burning sensation

Question 13

how would you manage erythropoietic protoporphyria?

Answer 13

6 monthly LFTs & RBC porphyrins 
visible light photoprotection measures 
prophylactic TL-01 phototherapy 
anti-oxidants 
avoid iron