3 - Agents used for Hyperkeratosis Flashcards Preview

Derm Pharm > 3 - Agents used for Hyperkeratosis > Flashcards

Flashcards in 3 - Agents used for Hyperkeratosis Deck (106):
1

The following are agents used for the treatment of hyperkeratosis:
(1) salicylic acid (BHA or a phenolic aromatic acid)
(2) sulfur
(3) tar
(4) urea
(5) lactic acid (AHA)
(6) glycolic acid (AHA)

True

2

Salicylic acid and salicylates (which are easily converted to salicylic acid) are present in willow bark, wintergreen leaves and sweet birch

True

3

Salicylic acid has been classified as either a beta-hydroxy acid (BHA) or more accurately as a phenolic aromatic acid

True (unlike a true BHA, salicylic acid has both the hydroxyl and carboxyl groups directly attached to an aromatic benzene ring and the hydroxyl group exhibits acid properties; whereas the hydroxyl group of a true BHA is neutral)

4

Salicylic acid is lipid soluble and therefore miscible with epidermal lipids

True (in contrast to AHA such as Glycolic acid and lactic acid which are water soluble)

5

Salicylic acid is lipid soluble and therefore miscible with sebaceous glands lipids in hair follicles

True (in contrast to AHA such as Glycolic acid and lactic acid which are water soluble)

6

Salicylic acid is lipid soluble and therefore can interact with lipids that surround keratinised cells

True (in contrast to AHA such as Glycolic acid and lactic acid which are water soluble)

7

Salicylic acid is lipid soluble and therefore is able to interact with multilamellar structures surrounding keratinocytes in the stratum corneum and in hair follicles

True (in contrast to AHA such as Glycolic acid and lactic acid which are water soluble)

8

Because of the greater lipophilic qualities of salicylic acid in contrast to the water solubility of AHA, the clinical effect of salicylic acid may be limited to the superficial epidermis

True (AHA free acids may penetrate deeper into the epidermis and dermis as well)

9

Salicylic acid has a pKa (acid dissociation constant) of 2.98 and must be formulated at a proper pH to allow enough free acid to be present to obtain a significant exfoliative effect

True (various formulations with concentrations of salicylic acid at a pH close to pKa give significantly more exfoliation than formulation at any pH significantly greater than the pKa)

10

Salicylic acid formulations with concentrations of at a pH close to its pKa (acid dissociation constant) give significantly more exfoliation than formulation at any pH significantly greater than the pKa

True (salicylic acid pKa = 2.98)

11

Salicylic acid has keratolytic and desmolytic effects

True (desmolytic more accurately describes the mechanism of action)

12

Salicylic acid and its derivatives have sunscreen effects (such as the UVB absorber octisalate/octyl salicylate)

True (therefore topical Salicylic acid which is frequently used in psoriasis can interfere with UVB phototherapy for psoriasis)

13

Salicylates such as acetylsalicylate (aspirin) and Salicylic acid have anti-inflammatory properties

True (the anti-inflammatory effect of a Salicylic acid is most pronounced at 0.5% and 5%)

14

Salicylic acid exerts its keratolytic and desmolytic effects by:
(1) reducing corneocyte adhesion
(2) loosening and causing detachment of corneocytes

True

15

The term 'desmolytic' is more preferable to 'keratolytic' in regard to the mechanism of action of salicylic acid as Salicylic acid disrupts the cellular junctions (desmosomes) rather than lysing/breaking intercellular keratin filaments

True (acts as an organic solvent to remove the intercellular lipid linking the cornified cells)

16

Salicylic acid causes a more irregular and thinner stratum corneum without altering the epidermal thickness

True (in contrast the AHA that thins the stratum corneum, but increases thickness of the viable epidermis and dermis)

17

Salicylic acid is used for the following hyperkeratotic disorders:
(1) calluses
(2) corns
(3) hyperkeratosis
(4) ichthyosis
(5) keratoderma

True
Calluses/corn = 2-20% Salicylic acid in collodion-based paint and gels, 10-50% Salicylic acid in a plaster
Hyperkeratosis = 6% Salicylic acid multi vesicular emulsion cream
Ichthyosis/keratoderma = 6% Salicylic acid + 60% propylene glycol + 20% ethanol

18

Salicylic acid is used for the following cosmetic indications:
(1) hyperpigmentation
(2) rejuvenation/peeling

True

19

Salicylic acid is used for the following papulosquamous dermatosis:
(1) psoriasis

True

20

Salicylic acid is used for the following cutaneous infections:
(1) dermatophyte infections
(2) verruca (HPV)

True
Dermatophyte = 6% Salicylic acid + 12% benzoic acid in wool fat and petrolatum (Whitfield's ointment), 10% Salicylic acid + 20% urea for avulsing toenails
Verruca = 2-20% Salicylic acid in collodion-based paint and gels, 10-50% Salicylic acid in a plaster

21

Salicylic acid is used for the following dermatitis:
(1) cradle cap
(2) seborrhoeic dermatitis

True
Shampoos with 2% Salicylic acid, often in combination with tar and Sulfur

22

Salicylic acid may be used in acne vulgaris due to its mild comedolytic effects

True

23

In the treatment of psoriasis, Salicylic acid is added into topical preparations containing dithranol to prevent its oxidation

True

24

In the treatment of psoriasis, the original Lassar's paste contained 2% Salicylic acid + 24% zinc oxide + 24% starch + 50% WSP

True (although compounds duplicating the original Lassar's paste should always be freshly prepared because the ingredients combine to form zinc salicylate on standing) - modern formulations of Lassar's paste do not contain Salicylic acid because of the interaction of salicylic acid and zinc oxide

25

In treatment of psoriasis, compounding calcipotriene with Salicylic acid should be avoided as this results in instability of calcipotriene when mixed with Salicylic acid

True

26

Salicylic acid has been used for pruritus

True (antipruritic formulations at a concentration of 1-2%)

27

Salicylic acid has been used for painful aphthous ulcers and for topical musculoskeletal symptomatic pain relief

True
Aphthous ulcers = choline salicylate
MSK pain = methyl salicylate found in oil of wintergreen

28

Salicylic has been used as a superficial peeling agent as part of Jessner's solution which consists of 14% Salicylic acid + 14% resorcinol + 14% lactic acid in ethanol

True

29

Salicylic acid in concentrations of 20-30% in a hydroethanolic vehicle is also used as a superficial chemical peel for acne, photodamage, and hyperpigmentation

True

30

The effect of salicylic acid in chemical peeling procedures is largely related to epidermal injury

True

31

50% Salicylic acid ointment has been used to treat severely photodamaged hands and forearms

True

32

1-2% Salicylic acid is used as an exfoliant to increase corneocyte shedding and improve the appearance of aged skin

True

33

Salicylic acid has been used in hyperhidrosis

True (2% Salicylic acid to 15% aluminium chloride hexahydrate is efficacious and less irritating than preparations that contained aluminium chloride hexahydrate only)

34

When applied topically to the skin, Salicylic acid is readily absorbed

True (risk of systemic absorption and salicylism)

35

Percutaneous absorption of salicylic acid is enhanced by incorporation into hydrophilic ointment

True (risk of systemic absorption and salicylism)

36

If Salicylic acid is applied to erythrodermic skin, it can be detected in the urine within 24 hours

True (risk of systemic absorption and salicylism)

37

Percutaneous absorption of salicylic acid is enhanced by tape stripping of the stratum corneum

True (risk of systemic absorption and salicylism)

38

Percutaneous absorption of salicylic acid is enhanced by application under occlusion

True (risk of systemic absorption and salicylism)

39

Systemic toxicity due to percutaneous absorption of salicylic acid is rare, but a potentially serious event as salicylates in high concentrations are toxic to the CNS

True

40

Salicylates in high concentrations causes CNS toxicity including nausea, vomiting, tinnitus, confusion, dizziness, delirium, psychosis, stupor, coma and death

True

41

Tinnitus due to salicylate toxicity is caused by increased labyrinthine pressure and effects on cochlear hair cells secondary to vasoconstriction in the auditory microvasculature

True

42

Salicylate toxicity stimulates the medullary respiratory centre in the brain that causes marked hyperventilation and respiratory alkalosis, and in infants and children metabolic acidosis may occur

True

43

Signs of salicylate toxicity generally occur when blood concentrations exceed 35 mg/dL

True

44

Salicylate systemic toxicity causes the following GI effects:
(1) nausea
(2) vomiting

True

45

Salicylate systemic toxicity causes the following neurological effects:
(1) confusion
(2) dizziness
(3) delirium
(4) psychosis
(5) stupor
(6) coma
(7) death

True

46

Salicylate systemic toxicity causes the following metabolic effects:
(1) respiratory alkalosis
(2) metabolic acidosis in infants and children
(3) hypoglycaemia

True

47

Tinnitus is an early warning sign of salicylate systemic toxicity

True

48

Salicylate systemic toxicity causes hyperventilation

True (stimulation of medullary respiratory centre in the brain)

49

Symptoms of Salicylate toxicity appeared early in the course of treatment, frequently within 2-3 days of initiating therapy

True

50

Salicylates affect glucose utilisation and may lead to hypoglycaemia, especially in patients with uraemia due to reduced protein binding of salicylates

True

51

Salicylic acid is only a weak contact sensitiser, and the incidence is rare

True

52

Sulfur has antiparasitic properties

True (used for scabies in topical formulations)

53

Sulfur has anti-acne properties

True (used for acne, Rosacea and perioral dermatitis)

54

Sulfur has anti-seborrhoeic properties

True (used for seborrhoeic dermatitis and pityriasis versicolor)

55

Sulfur is a yellow non-metallic element

True

56

The 2 Sulfur preparations used in dermatology include:
(1) sublimed Sulfur
(2) precipitated Sulfur (smaller particle size allowing for greater interaction with skin)

True
sublimed Sulfur = produced by direct conversion of crude Sulfur from solid phase to gas
precipitated Sulfur = produced by boiling sublimed Sulfur with lime and water and then adding hydrochloric acid resulting in very fine particles

57

Precipitated Sulfur is the most common Sulfur used in dermatology

True (sublimed Sulfur is also used, but not as common) - precipitated Sulfur has smaller particle size and has greater interaction with skin

58

Sulfur has keratolytic effects (breaking down of the stratum corneum) at high concentrations and although the exact mechanism is unknown, the interaction of Sulfur with cysteine in keratinocytes that leads to release of hydrogen sulfide probably accounts for the break down of keratin and cause dissolution of the stratum corneum

True (lower concentration Sulfur produces keratoplastic effects)

59

Sulfur has antifungal effects which relates to the formation of pentathionic acid by cutaneous bacteria and keratinocytes, as well as the keratolytic effects of Sulfur which causes shedding of infected stratum corneum

True

60

Sulfur has antiseptic properties

True

61

Sulfur has antibacterial effects as it demonstrates inhibitory effect on the growth of P. Acnes, some streptococci and staph aureus

True

62

Sulfur has keratoplastic effects (normalisation of keratinisation and epidermal cell maturation) at low concentrations, which also relates to the interaction between Sulfur and cysteine that promotes normal keratinisation

True (higher concentrations of Sulfur has keratolytic effects)

63

The use of Sulfur in the treatment of Rosacea may be due to killing of Demodex mites implicated as a causative factor in some cases of Rosacea (antiparasitic effects)

True

64

The action of Sulfur in scabies is poorly understood although the formation of hydrogen sulfide (from the interaction of Sulfur and cysteine) and polythionic acid which are toxic to the mite, and the shedding/keratolytic effects of the stratum corneum through which the mites burrows may be the mechanism of action in the treatment of scabies

True (Sulfur was used before the availability of permethrin, but there are no well designed studies regarding the efficacy and toxicity of Sulfur in the therapy of scabies)

65

Sulfur penetrates the skin within 2-8 hours of topical application

True

66

The anti-acne properties of Sulfur may not be related to its keratolytic effect, but may instead be related to non-specific irritant effects that lead to peeling (desquamative effects)

True

67

Fatal toxicity after Sulfur was applied to large areas of the skin of infants has been reported rarely

True

68

Sulfur may cause allergic contact dermatitis

True

69

Tar has antiproliferative effects on the epidermis and appears to exert its actions through suppression of DNA synthesis consequently leading to reduction of mitotic activity in the basal layer of the epidermis

True

70

In combination with UV light, tar reduced epidermal proliferation more effectively than with either treatment modality alone

True (the combination of tar and UV therapy for psoriasis is called 'Goeckerman regimen')

71

Tar (specifically bituminous marine fossil-derived tar) has anti-inflammatory activity caused by inhibition of chemotaxis of neutrophils due to leukotrienes

True

72

Tar preparations are useful topical therapy for inflammatory skin diseases such as psoriasis, atypical dermatitis, seborrhoeic dermatitis

True (can also be used in eczematous dermatitides, pityriasis versicolor and dermatophyte infections as tar has antifungal properties against yeast, dermatophytes and hypomycetes; vitiligo, pruritus)

73

Tar shampoos are commonly used to treat seborrhoeic dermatitis of the scalp

True (shale oils also have antifungal properties against yeast, dermatophytes and hypomycetes)

74

Tar has been associated with possible skin carcinogenesis but has been declared effective and safe as clinical studies in numerous patients demonstrated that the skin cancer incidence in these patients is no different from that of the general population

True (the skin cancer incidence is increased in patients with psoriasis who received extensive treatment with tar and UVR but the relative contributions of the UVR and the tar components to this carcinogenesis is unknown)

75

Scrotal SCC in association with tar exposure is a well-known occupationally induced cancer

True (although the use of protective clothing, better hygiene and less scrotal exposure to carcinogens made tar-induced scrotal SCC primarily of historical significance only)

76

The cancer potential of tar has been linked to its carcinogen content

True (major carcinogenic agents in tar are polyaromatic hydrocarbons such as benzapyrene, anthracene and pyridines)

77

Tar preparation of dermatologic importance are derived from 3 main organic sources:
(1) bituminous coal (crude coal tar)
(2) wood (wood tar)
(3) marine fossils (bituminous tar/sulfonated shale oil)

True

78

Crude coal tar derived from bituminous coal is the most widely used form of tar in dermatology and contains polyaromatic hydrocarbons (and the major carcinogenic agents benzapyrene, anthracene, pyridines), phenols and nitrogen bases

True

79

Wood tar derived from wood is also rich in polyaromatic hydrocarbons (just like crude coal tar), but have fewer carcinogenic agents (such as anthracene and pyridines) than crude coal tar; although is more irritating and toxic due to the higher phenol absorption properties

True

80

Bituminous tar/sulfonated shale oil derived from marine fossils has comparatively low levels of polyaromatic hydrocarbons carcinogenic agents (benzapyrene, anthracene, pyridines) than crude coal tar and wood tar

True

81

A major disadvantage of the use of tar is poor compliance due to the smell, appearance, and staining capacity

True (as a consequence crude coal tar has been modified to produce LPC)

82

Liquor picis carbonis (LPC) is an alcohol extract of crude coal tar that is more cosmetically acceptable, but is therapeutically inferior to crude coal tar

True (although patient acceptance of LPC exceeds that of other forms of tar)

83

Crude coal tar causes photosensitivity and is an adverse effect that is responsible (in part) for the therapeutic effect of the Goeckerman regimen

True (wood tar and bituminous tar/sulfonated shale oil do not photosensitise and are more cosmetically attractive than crude coal tar)
Goeckerman regimen = tar + UV therapy

84

In contrast to crude coal tar, wood tar and bituminous tar/sulfonated shale oil do not photosensitise and are more cosmetically attractive than crude coal tar

True

85

Tar smarts is the phototoxicity from natural sunlight and inadvertent tar exposure, due to the UVR wavelengths in the UVA spectrum (320-400 nm)

True

86

Phototoxic and photoallergic reactions to tar products have been reported

True

87

More often allergic contact dermatitis appears to occur with wood tar and may cross-react with colophony, balsam of Peru, and turpentine

True

88

The phototoxic dermatitis from coal tar products can result in poikiloderma

True

89

The acute toxic potential of tar (mainly wood tar due to its high phenol content) is due to phenol

True (newer products have been manufactured with reduced phenol content to minimise the risk for phenol toxicity)

90

Tar products may cause irritant reactions as well

True

91

Tar can cause pruritus

True

92

Tar can cause folliculitis

True

93

Tar can cause comedones

True

94

Tar can cause acneiform eruptions

True

95

Tar can cause keratoses (tar warts)

True

96

Tar can cause keratoacanthomas

True

97

Urea has antimicrobial properties

True (inhibit the growth of some microorganisms)

98

Urea has humectant (moisturising properties that reduce transepidermal water loss and increase skin hydration) properties by absorbing water from the atmosphere in high humidity environment due to its high water solubility and low water vapour pressure

True (enhancer of protein-water binding capacity)

99

Urea has keratolytic properties by:
(1) incorporating itself into the stratum corneum and breaking hydrogen bonds to reach the interior of epidermal keratins
(2) water solubility and water-binding capacity giving it the humectant characteristics leading to increased desquamation of corneocytes

True (high concentrations of urea is a protein solvent and denaturant and has the ability to macerate dystrophic nails due to its hydrating properties)

100

Urea is bipolar, rendering the molecule water soluble and capable of ionic interactions with salt solutions leading to an increase in water-binding capacity when mixed with sodium chloride

True

101

As urea is the end product of the catabolism of animal proteins, urea is not an energy source for most pathogenic bacteria and therefore does not promote pathogenic bacterial growth

True

102

Urea enhances the percutaneous absorption of various chemicals and pharmaceutical agents

True

103

Urea 10-25% has humectant, antipruritic and mild keratolytic properties and is used for:
(1) Xerosis
(2) hyperkeratosis
(3) atopic dermatitis
(4) xerotic dermatitis
(5) keratosis pilaris
(6) keratodermas
(7) icthyosis

True

104

Urea 40-50% has humectant and keratolytic properties and is used for:
(1) calluses
(2) chemical avulsion of dystrophic nails
(3) hyperkeratosis

True

105

Topical urea preparations can cause irritant reactions (related to the high acidity of the preparations) and maceration (owing to the humectant properties), but are these more likely with the higher concentration products and especially if used under occlusion

True

106

Application of urea in excoriated or fissured skin can produce stinging and irritation and is related to the high acidity of the preparations (usually pH 3 or less)

True (new stabilised preparations claim less acidity and consequently less irritation)