Photodermatology Flashcards
Inadequate sun exposure in conjunction with a diet deficient in vitamin D can lead to what condition?
Osteomalacia (rickets in children)
What are the hazards of UV radiation exposure?
Sunburn Eyes - conjunctivitis, keratitis, cateract Skin cancer Photoageing Photosensitivity - photodermatoses
Out of UVA, UVB and UVC which has the longest wavelength?
UVA (then B and C)
The ozone layer blocks which type of UV?
UVC
Do windows block UVA or UVB?
UVB
Which UV is most biologically potent?
UVC (Then B and A)
How many times more potent is UVB compared to UVA?
1000 times
Which UV do most sunbeds use?
Fluorescent UVA
Which UV is good for psoriasis?
UVB
What is PUVA?
Light therapy using psoralen and UVA
What can PUVA be used to treat?
Psoriasis
Eczema
Vitiligo
Cutaneous T-cell lymphoma
What are the Fitzpatrick skin types?
I - Only burns II - Burns, can tan III - Tans, can burn IV - Tans V - Dark brown skin VI - Black skin
What’s a mediator for UVA erythema?
Oxygen
What’s a mediator for UVB erythema?
Prostaglandins
Are melanomas caused by cumulative sun exposure or acute sunburns?
Acute sunburns
What is the commonest cancer in caucasians?
Basal Cell Carcinoma
What type of hypersensitivity is polymorphic light eruption?
Type 4
Which antibiotics can cause drug-induced photosensitivity?
Sulphonamides
Tetracyclines
Fluoroquinolones
Which diuretics can cause drug-induced photosensitivity?
Thiazides
Frusemide
Other than antibiotics and diuretics which drugs can cause drug-induced photosensitivity?
Psoralens
NSAIDS
Quinine
Amiodarone
What investigation results may be found in porphyria cutanea tarda (PCT)?
Abnormal LFTs
Iron overload
What conditions have a high prevalence in patients with PCT?
Hepatitis C
HIV
Haemochromatosis
In PCT what may be found in the urine?
High levels of uroporphyrinogen
