2 - Topical Contact Allergens Flashcards Preview

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Flashcards in 2 - Topical Contact Allergens Deck (37):
1

Topical contact allergens induces an allergic contact dermatitis in a previously unsensitised host

True

2

Topical contact allergens treat various dermatoses by maintaining the allergic contact dermatitis at the site of the skin disease being treated

True

3

The ideal contact allergen is a potent contact sensitiser

True

4

The ideal contact allergen should not be widely found in the environment

True

5

The ideal contact allergen does not cause significant adverse effects

True

6

The ideal contact allergen does not cross-sensitise with other substances

True

7

It is not completely known how topical contact allergens may improve alopecia areata or viral warts

True

8

The 'antigenic competition' theory has been postulated in the mechanism of action of topical contact allergens in alopecia areata, in that an immunoreaction to one antigen may inhibit the development of the immune response to another unrelated antigen

True (the ratio of CD4:CD8 peribulbar T cell infiltrate changes to 1:1 from 4:1 to reflect a relative increase in peribulbar CD8 T cells)

9

Long term treatment of alopecia areata with topical contact allergens DPCP and SADBE leads to significant non-specific systemic suppression of delayed hypersensitivity reactions

True

10

DPCP treatment of alopecia areata reduces the abnormal expression of Human Leukocyte Antigen (HLA) in the epithelium of lower hair follicles

True

11

Long term treatment of alopecia areata with DPCP leads to recovery of hair follicles by driving auto reactive T cells into activation-induced cell death

True

12

The mechanism of action of topical contact allergens in warts may be a result of a non-specific cell-mediated immune response that triggers virus-infected cell lysis and death

True

13

Both DPCP and SADBE are non-mutagenic on the Ames test

True (in contrast to DNCB which is mutagenic)

14

The synthetic precursor of DPCP is a potential contaminant of commercially obtained samples and a potent mutagen

True (although DPCP itself is not a mutagen) - presence of the contaminant may be screened before use and periodically thereafter using liquid chromatography

15

DPCP is light sensitive

True

16

DPCP's photolysis product (diphenylacetylene) is not mutagenic

True

17

Acetone is a standard solvent for DPCP and SADBE

True (acetone is a strong light absorber and dries rapidly) - DPCP is more stable in acetone than SADBE

18

Women of child bearing potential should have a negative pregnancy test before starting DPCP and advised to use reliable birth control during treatment

True

19

In alopecia areata, Eyelashes should not be treated with DPCP

True

20

The addition of topical minoxidil did not add a significant clinical benefit in patients treated with DPCP for alopecia areata

True

21

Fexofenadine hydrochloride can enhance the efficacy of DPCP or SADBE in alopecia areata

True

22

Oral administration of the immunomodulatory agent inosine pranobex did not enhance the efficacy of DPCP in a patient with alopecia totalis

True

23

Regional lymphadenopathy is a common adverse effect from topical DPCP and SADBE

True

24

Localised contact eczema and spread of contact eczema to distant sites (autoeczematisation) are common in topical DPCP and SADBE

True

25

Vitiligo and leukoderma are rare adverse events in topical DPCP and SADBE

True

26

Dark skin individuals should be treated with topical DPCP and SADBE with extreme caution

True (rare event of vitiligo, leukoderma dyschromia of Confetti)

27

Dyschromia of confetti (a pattern of hyperpigmentation and hypopigmentation) may result from topical DPCP application on treated and non-treated sites

True (unclear if this is a toxic or allergic reaction)

28

Erythema multiforme and erythema multiforme-like eruption are uncommon adverse effects from topical DPCP

True

29

Urticaria and contact urticaria are rare adverse effects from topical DPCP

True

30

Topical DPCP and SADBE do not cause significant blood abnormalities

True

31

Topical DPCP may be used in the treatment of melanoma and vitiligo

True

32

SADBE in acetone requires refrigeration

True (not as stable as DPCP in acetone)

33

The castling phenomenon (hair regrowth at sites distant from the site of SADBE application, or denser and faster regrowth on the untreated site than on the treated site) has been noted in alopecia areata patients treated with both topical DPCP and SADBE

True

34

Benign lymphoplasia at the treated site may occur with topical SADBE

True

35

DNCB is mutagenic

True

36

>40% of DNCB is absorbed systemically

True (DNCB has largely been replaced by DPCP and SADBE)

37

Topical contact allergens (DPCP and DNCB) showed better results for bald areas > 50cm2 than intralesional injection of Triamcinolone Acetonide

True