Solar dermatitis

Question 1

Name 7 Ddxs for this

Answer 1

Solar dermatitis

Dermatophytosis

Notoedric mange

Fight wounds

Vasculitis

Frostbite or cryoglubulinemia

DLE, SLE

PE, PF

Question 2

Match

UVA

UVB

UVC

<290 nm

290-320 nm

320-400 nm

Answer 2

UVA 320-400 nm

UVB 290-320 nm

UVC <290 nm

Question 3

True/False

UVA wavelength penetrates deeper into the skin than UVB

Answer 3

True

Question 4

Which UV spectrum is associated with phototsensitivity reactions?

Answer 4

UVA

Question 5

What wavelength is most damaging to the skin?

Answer 5

320-340 nm

Question 6

What are chromophores?

Answer 6

Light absorbing molecules

Question 7

Name the chromophores in the skin

Answer 7

Keratin proteins, blood, hemoglobin, porphyrin, carotene, nucleic acids, melanin, lipoproteins, pepitde bonds and aromatic amino acids (such as tyrosine, tryptophan and histidine)

Question 8

What are the natural UVL barriers in the skin?

Answer 8

Stratum corneum, melanin, blood, and carotenes

Question 9

What is the difference between photosensitivity and photo toxicitiy?

Answer 9

Photosensitivity = when the skin has increased susceptibility to the damagin effects of UVL because of the production, ingestion, injection of, or contact with photodynamic agent

Photo toxicity = CLASSIC sun burn reaction; dose related response to light exposure

Question 10

True/False

Solar dermatitis is a photo toxic and photo sensitivity reaction

Answer 10

False

Solar dermatitis is purely a photo toxic reaction (sunburn) and has no apparent relationship to a hypersensitivity state

Question 11

Name the skin structures involved in photo toxicity

Answer 11

Epidermis and blood vessels of the superficial and deeper vascular plexus

Question 12

What are sun burn cells?

Answer 12

Vacuolated keratinocytes post exposure to UVB / UVC

Question 13

Name the changes that occur in the skin after UVB and UVC exposure

Answer 13

Vacuolated keratinocytes in the superficial epidermia, apoptotic KCs, vascular dilatation and leakage, depletion of Langerhans and mast cells

Question 14

What are the oxygen intermediates that may be important in the pathogenesis of solar damage?

Answer 14

Superoxide radical, hydrogen peroxide and hydroxyl radical

Question 15

What do oxygen intermediates do?

Answer 15

Deplete antioxidants, recruits neutrophils and can destroy connective tissue

Question 16

What is the initial lesion in canine nasal solar dermatitis?

Answer 16

Erythema and scaling of non pigmented skin

Question 17

Name 7 DDx for this (facial dermatosis)

Answer 17

DLE, SLE, dermatomyositis, epidermolysis bullosa, PF, PE, drug reaction, infectious folliculitis and furunculosis due to bacteial, dermatophyte, Demodex, yeast or leishmanial infection

Question 18

What is solar elastosis?

Answer 18

Basophilic degeneration of elastin

Question 19

What special stain is needed to highlight solar elastosis?

Answer 19

PAS stain

Question 20

The damaging effects on cutaneous immunity of UVB is mediated by which cytokine?

Answer 20

TNF-a

Question 21

Clinically, how would you differentiate solar dermatitis vs photosensitivity?

Answer 21

Photosensitivity occur in well-haired regions of the body (light color)