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Derm Pharm 2020 > 3 - Agents used for Hyperkeratosis > Flashcards

3 - Agents used for Hyperkeratosis Flashcards

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Dermatology Board Prep flashcards
1
Q

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)

A

True

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2
Q

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

A

True

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3
Q

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

A

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)

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4
Q

Salicylic acid is lipid soluble and therefore miscible with epidermal lipids

A

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

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5
Q

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

A

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

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6
Q

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

A

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

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7
Q

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

A

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

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8
Q

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

A

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

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9
Q

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

A

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)

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10
Q

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

A

True (salicylic acid pKa = 2.98)

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11
Q

Salicylic acid has keratolytic and desmolytic effects

A

True (desmolytic more accurately describes the mechanism of action)

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12
Q

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

A

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

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13
Q

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

A

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

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14
Q

Salicylic acid exerts its keratolytic and desmolytic effects by:

(1) reducing corneocyte adhesion
(2) loosening and causing detachment of corneocytes

A

True

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15
Q

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

A

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

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16
Q

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

A

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

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17
Q

Salicylic acid is used for the following hyperkeratotic disorders:

(1) calluses
(2) corns
(3) hyperkeratosis
(4) ichthyosis
(5) keratoderma

A

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

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18
Q

Salicylic acid is used for the following cosmetic indications:

(1) hyperpigmentation
(2) rejuvenation/peeling

A

True

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19
Q

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

A

True

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20
Q

Salicylic acid is used for the following cutaneous infections:

(1) dermatophyte infections
(2) verruca (HPV)

A

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

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21
Q

Salicylic acid is used for the following dermatitis:

(1) cradle cap
(2) seborrhoeic dermatitis

A

True

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

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22
Q

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

A

True

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23
Q

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

A

True

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24
Q

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

A

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

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25
Q

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

A

True

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26
Q

Salicylic acid has been used for pruritus

A

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

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27
Q

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

A

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

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28
Q

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

A

True

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29
Q

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

A

True

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30
Q

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

A

True

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31
Q

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

A

True

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32
Q

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

A

True

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33
Q

Salicylic acid has been used in hyperhidrosis

A

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

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34
Q

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

A

True (risk of systemic absorption and salicylism)

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35
Q

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

A

True (risk of systemic absorption and salicylism)

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36
Q

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

A

True (risk of systemic absorption and salicylism)

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37
Q

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

A

True (risk of systemic absorption and salicylism)

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38
Q

Percutaneous absorption of salicylic acid is enhanced by application under occlusion

A

True (risk of systemic absorption and salicylism)

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39
Q

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

A

True

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40
Q

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

A

True

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41
Q

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

A

True

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42
Q

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

A

True

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43
Q

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

A

True

44
Q

Salicylate systemic toxicity causes the following GI effects:

(1) nausea
(2) vomiting

A

True

45
Q

Salicylate systemic toxicity causes the following neurological effects:

(1) confusion
(2) dizziness
(3) delirium
(4) psychosis
(5) stupor
(6) coma
(7) death

A

True

46
Q

Salicylate systemic toxicity causes the following metabolic effects:

(1) respiratory alkalosis
(2) metabolic acidosis in infants and children
(3) hypoglycaemia

A

True

47
Q

Tinnitus is an early warning sign of salicylate systemic toxicity

A

True

48
Q

Salicylate systemic toxicity causes hyperventilation

A

True (stimulation of medullary respiratory centre in the brain)

49
Q

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

A

True

50
Q

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

A

True

51
Q

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

A

True

52
Q

Sulfur has antiparasitic properties

A

True (used for scabies in topical formulations)

53
Q

Sulfur has anti-acne properties

A

True (used for acne, Rosacea and perioral dermatitis)

54
Q

Sulfur has anti-seborrhoeic properties

A

True (used for seborrhoeic dermatitis and pityriasis versicolor)

55
Q

Sulfur is a yellow non-metallic element

A

True

56
Q

The 2 Sulfur preparations used in dermatology include:

1) sublimed Sulfur
(2) precipitated Sulfur (smaller particle size allowing for greater interaction with skin

A

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
Q

Precipitated Sulfur is the most common Sulfur used in dermatology

A

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

58
Q

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

A

True (lower concentration Sulfur produces keratoplastic effects)

59
Q

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

A

True

60
Q

Sulfur has antiseptic properties

A

True

61
Q

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

A

True

62
Q

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

A

True (higher concentrations of Sulfur has keratolytic effects)

63
Q

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)

A

True

64
Q

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

A

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
Q

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

A

True

66
Q

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)

A

True

67
Q

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

A

True

68
Q

Sulfur may cause allergic contact dermatitis

A

True

69
Q

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

A

True

70
Q

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

A

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

71
Q

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

A

True

72
Q

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

A

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
Q

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

A

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

74
Q

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

A

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
Q

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

A

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
Q

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

A

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

77
Q

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)

A

True

78
Q

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

A

True

79
Q

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

A

True

80
Q

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

A

True

81
Q

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

A

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

82
Q

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

A

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

83
Q

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

A

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
Q

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

A

True

85
Q

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

A

True

86
Q

Phototoxic and photoallergic reactions to tar products have been reported

A

True

87
Q

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

A

True

88
Q

The phototoxic dermatitis from coal tar products can result in poikiloderma

A

True

89
Q

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

A

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

90
Q

Tar products may cause irritant reactions as well

A

True

91
Q

Tar can cause pruritus

A

True

92
Q

Tar can cause folliculitis

A

True

93
Q

Tar can cause comedones

A

True

94
Q

Tar can cause acneiform eruptions

A

True

95
Q

Tar can cause keratoses (tar warts)

A

True

96
Q

Tar can cause keratoacanthomas

A

True

97
Q

Urea has antimicrobial properties

A

True (inhibit the growth of some microorganisms)

98
Q

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

A

True (enhancer of protein-water binding capacity)

99
Q

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

A

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
Q

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

A

True

101
Q

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

A

True

102
Q

Urea enhances the percutaneous absorption of various chemicals and pharmaceutical agents

A

True

103
Q

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

A

True

104
Q

Urea 40-50% has humectant and keratolytic properties and is used for:

(1) calluses
(2) chemical avulsion of dystrophic nails
(3) hyperkeratosis

A

True

105
Q

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

A

True

106
Q

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)

A

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

Derm Pharm 2020 (47 decks)

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