3 - PUVA, NB-UVB and UVA-1 phototherapy

Question 1

UVA wavelength is 320-400nm

Answer 1

True

Question 2

UVB wavelength is 311nm

Answer 2

True

Question 3

Psoralen plus ultraviolet A (PUVA) photochemotherapy is the photochemical interaction between a psoralen medication and UVA radiation

Answer 3

True

Question 4

Psoralens are naturally occurring compounds acting as natural insecticides

Answer 4

True

Question 5

Human contact with plants containing psoralens and subsequent exposure to sunlight results in phytophotodermatitis

Answer 5

True

Question 6

Phytophotodermatitis represents an acute phototoxic reaction in the skin manifested as erythema, blistering and pigmentation

Answer 6

True

Question 7

The presence of psoralen in the skin before and after exposure can be harmful through unintentional exposure to sunlight resulting in undesirable phototoxicity

Answer 7

True

Question 8

Psoralens are lipophilic and poorly soluble in water

Answer 8

True

Question 9

There are 2 types of psoralens available, namely 8-MOP (methoxsalen) and 5-MOP (bergapten) where 8-MOP is more water soluble than 5-MOP

Answer 9

True

Question 10

The water solubility of psoralens determines the bioavailability of these compounds

Answer 10

True

Question 11

8-MOP (Methoxsalen) is available as 2 formulations of dissolved psoralen (Oxsoralen Ultra) and micronised crystals of 8-MOP

Answer 11

True

Question 12

Dissolved psoralen (Oxsoralen Ultra) is rapidly and more completely absorbed as compared to the 8-MOP micronised crystals

Answer 12

True (accounts for dissolved psoralen being dosed at 0.4mg/kg and taken 1 hour prior to UVA and micronised crystals 8-MOP being dosed at 0.6mg/kg and 2 hours prior to UVA)

Question 13

High fat foods can slow down the absorption of psoralens

Answer 13

True (psoralens is ideally taken under fasting conditions although food intake can be used to alleviate the nausea associated with high serum level of the drug)

Question 14

Nausea is associated with high serum levels of psoralen

Answer 14

True (food intake with the drug can alleviate this adverse effect)

Question 15

Psoralens exhibit first pass metabolism in the liver and intestines

Answer 15

True (therefore doses <20mg may not be clinically effective)

Question 16

Psoralens highly bind to serum albumin

Answer 16

True

Question 17

8-MOP (Methoxsalen) is more photoactive than 5-MOP (Bergapten)

Answer 17

True

Question 18

The physical formulation of psoralen influences its absorption

Answer 18

True (8-MOP dissolved psoralen more readily absorbed than 8-MOP micronised crystals)

Question 19

Methoxsalen (8-MOP) is completely metabolised in the liver through the CYP 450 system

Answer 19

True

Question 20

Cytochrome P450 inducers have an effect on the metabolism of psoralens

Answer 20

True (cytochrome P450 inducers enhance and accelerate the metabolism of 8-MOP therefore reducing the biological effect of PUVA)

Question 21

Most of 8-MOP is excreted in the kidneys

Answer 21

True

Question 22

The peak of the absorption spectrum for psoralen molecules to be activated to the excited singlet state is in the region of 320-330nm

Answer 22

True

Question 23

PUVA therapy suppresses DNA synthesis through the formation of monoadducts and cross links in the DNA

Answer 23

True

Question 24

PUVA therapy causes selective immunosuppression

Answer 24

True

Question 25

NB-UVB phototherapy is almost as effective as PUVA for psoriasis not involving the palms and soles

Answer 25

True

Question 26

NB-UVB has replaced PUVA as the treatment of choice for vitiligo as both treatments have comparable efficacy but NB-UVB is simpler

Answer 26

True

Question 27

Vitiligo on the face and torso are more responsive to phototherapy than on the limbs

Answer 27

True

Question 28

The eczematous and plaque stages of mycosis fungoides respond to PUVA

Answer 28

True

Question 29

The tumour stage of mycosis fungoides does not usually respond to PUVA

Answer 29

True (PUVA is usually not effective in the tumour phase of the disease)

Question 30

Sezary syndrome is not responsive to PUVA

Answer 30

True

Question 31

Patients with various photodermatoses can be desensitised by prophylactic exposure to a brief course of PUVA

Answer 31

True

Question 32

Pemphigoid is contraindicated in PUVA and NB-UVB

Answer 32

True

Question 33

Pemphigus is contraindicated in PUVA and NB-UVB

Answer 33

True

Question 34

Lactation is contraindicated in PUVA

Answer 34

True (because psoralens is probably secreted in breast milk)

Question 35

Lupus erythematosus with photosensitivity is contraindicated in PUVA and NB-UVB

Answer 35

True

Question 36

Xeroderma pigmentosum is contraindicated in PUVA and NB-UVB

Answer 36

True

Question 37

A 25% reduction in PUVA dose should be considered in patients taking photosensitising agents

Answer 37

True

Question 38

PUVA dose should be readjusted when patient is concurrently on doxycycline

Answer 38

True (photosensitising agent)

Question 39

PUVA dose should be readjusted when patient is concurrently on fluoroquinolones

Answer 39

True (lomefloxacin and sparfloxacin are photosensitising agents)

Question 40

The PUVA radiation dose is dependant on skin phototype

Answer 40

True

Question 41

If widespread erythema is present post PUVA, treatment should be stopped until the erythema clears

Answer 41

True

Question 42

When >95% of the psoriasis area has cleared post PUVA, the patient is stepped down to a maintenance schedule of PUVA

Answer 42

True

Question 43

If a significant (>5%) amount of psoriasis begins to return then the frequency of PUVA can be increased or stepped up to a clearance schedule

Answer 43

True

Question 44

Areas shielded from PUVA therapy should be concurrently managed with topical corticosteroid therapy

Answer 44

True

Question 45

Eye protection with UVA blocking glasses is required for PUVA therapy

Answer 45

True (required from time of psoralen ingestion until sunset that day when the patient is exposed to sunlight)

Question 46

A sunscreen with at least SPF 15 ideally includes avobenzone as an ingredient is advised for photoprotection from psoralen phototoxic reaction

Answer 46

True

Question 47

Nausea correlates with the serum level of psoralen

Answer 47

True (most common adverse effect)

Question 48

The PUVA itch (pruritus) and subacute phototoxicity are indications for stopping treatment until they clear

Answer 48

True

Question 49

Symptomatic erythema is the most common phototoxic reaction

Answer 49

True (10% of patients)

Question 50

PUVA may cause CNS disturbances

Answer 50

True

Question 51

PUVA may cause depression

Answer 51

True

Question 52

PUVA may cause headaches

Answer 52

True

Question 53

PUVA may cause hyperactivity

Answer 53

True

Question 54

PUVA lentigines is an association of PUVA treatment

Answer 54

True

Question 55

NMSC incidence is markedly increased in patients who receive high cumulative UVA exposure

Answer 55

True (dose dependant)

Question 56

The SCC is PUVA patients are not biologically more aggressive than actinically induced SCCs in immunocompetent patients

Answer 56

True

Question 57

There is an increased risk of SCC on male genitalia with PUVA treatment

Answer 57

True

Question 58

PUVA may cause herpes simplex virus recurrences

Answer 58

True

Question 59

There is no increased incidence of cataracts with PUVA

Answer 59

True

Question 60

Thiazides diuretics do not cause acute phototoxic erythema with PUVA

Answer 60

True (though a potentially photoactive agent, thiazides diuretics do not cause phototoxicity with PUVA)

Question 61

Carbamazepine may reduce the effectiveness of PUVA

Answer 61

True (carbamazepine is a CYP 450 enzyme inducer and enhances the metabolism of psoralen)

Question 62

Phenytoin may reduce the effectiveness of PUVA

Answer 62

True (phenytoin is a CYP 450 enzyme inducer and enhances the metabolism of psoralen)

Question 63

Other CYP 450 inducers may reduce the effectiveness of PUVA

Answer 63

True (enhance the metabolism of psoralen)

Question 64

Skin cancer is the most important adverse effect of long term PUVA treatment

Answer 64

True (need for long term skin checks even after cessation of PUVA)

Question 65

The peak of the action spectrum for phototherapy of psoriasis is in the 320-340nm spectrum

Answer 65

True

Question 66

UVB is absorbed in the epidermis and papillary dermis

Answer 66

True

Question 67

UVA wavelengths generally penetrate to the mid dermis

Answer 67

True

Question 68

Topical emollients are advised before NB-UVB to make lesions more transparent

Answer 68

True

Question 69

Bullae may appear on psoriatic plaques after NB-UVB phototherapy

Answer 69

True

Question 70

Lupus erythematosus may be a consequence of NB-UVB treatment

Answer 70

True

Question 71

Pemphigus may be a consequence of NB-UVB treatment

Answer 71

True

Question 72

Pemphigoid may be a consequence of NB-UVB treatment

Answer 72

True

Question 73

Recurrent herpes labialis may be an adverse effect of NB-UVB treatment

Answer 73

True

Question 74

Polymorphous light eruption can be an adverse effect of NB-UVB treatment

Answer 74

True

Question 75

UVA-1 wavelength is 340-400nm

Answer 75

True

Question 76

UVA-1 treatment is equivalent to NB-UVB and UVA treatment

Answer 76

True (no clear advantage of UVA-1)

Question 77

UVA-1 produces DNA damage in vivo and in vitro

Answer 77

True

Question 78

Erythema is the main short term effect of UVA-1 phototherapy

Answer 78

True

Question 79

Erythema from UVA-1 phototherapy is usually asymptomatic

Answer 79

True (usually asymptomatic and does not interfere with treatment)