3 - Alpha-Hydroxy Acids Flashcards

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1
Q

Alpha-hydroxy acids (AHA) are a family of carboxylic acids with a hydroxyl group on the adjacent (or alpha) carbon

A

True

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2
Q

The AHA are:

(1) Glycolic acid - 2 carbons
(2) Lactic acid - 3 carbons
(3) Malic acid - 4 carbons
(4) Tartaric acid - 4 carbons
(5) Citric acid - 6 carbons
(6) Mandelic acid - 8 carbons

A

True (Glycolic acid and lactic acid are most commonly used)

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3
Q

The most commonly used AHA are:

(1) Glycolic acid
(2) Lactic acid

A

True

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4
Q

The higher molecular weight AHA such as Malic acid, tartaric acid, citric acid and Mandelic acid are not as widely used as these do not penetrate the stratum corneum as well as Glycolic acid and Lactic acid

A

True

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5
Q

Glycolic acid is derived from sugar cane

A

True

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6
Q

Lactic acid is derived from milk

A

True

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7
Q

The AHA used in practice are chemically synthesised

A

True

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8
Q

Glycolic acid is the smallest of the AHA (2 carbon molecule)

A

True

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9
Q

Glycolic acid is stable

A

True

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10
Q

Glycolic acid is colourless

A

True

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11
Q

Glycolic acid is odourless

A

True

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12
Q

Glycolic acid is water-soluble

A

True

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13
Q

Glycolic acid is non-toxic if ingested

A

True

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14
Q

Lactic acid is a 3 carbon AHA molecule which can exist in several isomeric forms

A

True

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15
Q

Polyhydroxy acids (PHA) are also a family of carboxylic acids but are longer carboxylic acids with >2 hydroxyl groups, 1 of which is attached to the (alpha) carbon

A

True (owing to their larger size, PHA have a slower rate of absorption into the skin compared to AHA)

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16
Q

Owing to their larger size, PHA have a slower rate of absorption into the skin compared to AHA

A

True

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17
Q

The principal PHA are:

(1) gluconolactone
(2) galactose
(3) lactobionic acid - polymer of galactose and gluconolactone derived from lactose in cow’s milk

A

True

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18
Q

The PHA (galactose, gluconolactone, and lactobionic acid) contain more hydroxyl groups than AHA, therefore allowing them to bind more water than the smaller AHA

A

True (thus PHA have greater humectant and moisturising properties)

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19
Q

All AHA cause detachment of keratinocytes by promoting the degradation of corneodesmosomes, thereby accelerating stratum corneum turnover (epidermal effects)

A

True

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20
Q

AHA are hypothesised to decrease the calcium ion concentration in the epidermis, causing loss of calcium ions from the cell junctions which lead to desquamation, thereby promoting keratinocyte proliferation and retard keratinocyte differentiation (epidermal effects)

A

True (hence giving the skin a more youthful appearance)

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21
Q

When AHA are consistently applied to rough and dry skin, regulation of keratinisation yields a smoother less scaly surface (epidermal effects)

A

True

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22
Q

Desquamation from follicular orifices induced by AHA cleanses the pores and prevents follicular occlusion (epidermal effects)

A

True

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23
Q

Patients using AHA products note the control of dry skin, ichthyosis and acne, as well as disappearance of solar lentigines (epidermal effects)

A

True (regulation of keratinisation and desquamation)

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24
Q

Higher concentration AHA products not only diminish corneocyte cohesion, but can also reduce melanin synthesis (epidermal effects)

A

True (therefore this melanin inhibitory effect combined with epidermal remodelling/regulation of keratinisation makes the higher concentration AHA potentially useful for treating seborrhoeic keratoses, AKs, verrucae and facial rhytides)

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25
Q

AHA causes:

(1) epidermal effects
(2) dermal effects

A

True

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26
Q

Long term use of AHA produces measurable dermal effects including increased glycosaminoglycans, increased collagen density, disbursement of melanin, and improved quality of elastic fibres (improved dermal ground substances)

A

True

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27
Q

Long term use of AHA causes increase thickness of the viable epidermis and papillary dermis, without any inflammation (epidermal and dermal effects)

A

True

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28
Q

AHA causes the increase in type I collagen and intercellular ground substances, namely hyaluronic acid, that leads to increased dermal hydration and thickness and provides an aqueous environment for the diffusion of nutrients and toxins (dermal effects)

A

True

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29
Q

AHA causes a decrease in overall photodamage (epidermal and dermal effects)

A

True

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30
Q

AHA does not cause increase in dermal vasculature

A

True (this is in contrast to topical retinoids)

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31
Q

AHA may reverse the epidermal atrophic changes that are associated with topical corticosteroid treatment

A

True

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32
Q

PHA (gluconolactone, galactose, lactobionic acid) have a similar mechanism of action to AHA (Glycolic acid, lactic acid) as well as additional humectant and moisturising properties

A

True (PHA have more hydroxyl groups than AHA and therefore a greater water binding capacity)

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33
Q

PHA (gluconolactone, galactose, lactobionic acid) treated skin shows less transepidermal water loss and less skin irritation than AHA (Glycolic acid, lactic acid) treated skin when challenged with sodium lauryl sulfate

A

True (PHA have more hydroxyl groups than AHA and therefore a greater water binding capacity)

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34
Q

PHA (gluconolactone, galactose, lactobionic acid) are used in many cosmetic formulations because they produce similar results to AHA and are tolerated by more sensitive skin types

A

True (PHA have more hydroxyl groups than AHA and therefore a greater water binding capacity)

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35
Q

AHA produce stratum corneum response only with the following:

(1) <10% AHA application daily with pH >3
(2) high % AHA in short exposure times with pH <3

A

True

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36
Q

AHA produces both epidermal and dermal response with the following:

(1) single exposure to un-neutralised high % AHA
(2) repeated exposures to low % AHA with pH<3
(3) repeated exposures to high % AHA with pH>3

A

True

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37
Q

AHA is used in xerosis

A

True (reversal of hyperkeratosis, increase in viable epidermis and dermal thickness)

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38
Q

AHA is used in ichthyosis

A

True (reversal of hyperkeratosis, increase in viable epidermis and dermal thickness)

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39
Q

AHA is used in rhytides

A

True (increased production of collagen and intercellular ground substances, causing reversal of the epidermal and dermal markers of photoaging)

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40
Q

AHA is used in dermatoheliosis

A

True (increased production of collagen and intercellular ground substances, causing reversal of the epidermal and dermal markers of photoaging)

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41
Q

AHA is used to reverse the changes seen in brittle aged nails

A

True

42
Q

AHA is used in acne vulgaris because of its unique effect of superficial and controlled desquamation on the stratum corneum

A

True (5-10% once to twice daily as a home regimen, 35-70% for short exposures in the office setting as a superficial chemical peel)

43
Q

AHA is used in Rosacea

A

True

44
Q

AHA (specifically Glycolic acid and lactic acid) is effective in hyperpigmentation and pigmented lesions such as solar lentigines, melasma

A

True (decreased melanin in the epidermis on histology may be related to epidermal remodelling and turnover, as well as tyrosinase activity)

45
Q

AHA is used in actinic keratosis as a pre-treatment regimen prior to topical 5-FU cream as this resulted in shorter healing time than 5-FU monotherapy and equivalent efficacy in the reduction of AKs

A

True (20% Glycolic acid peels once weekly for 4 weeks > topical 5-FU cream daily for 4 weeks)

46
Q

It was once thought that thinning of the stratum corneum in normal skin might increase water loss and cause skin sensitivity to potentially irritating chemicals, however treatment with low concentration Glycolic acid does not affect the organisation of barrier lipids in the stratum corneum or increase transepidermal water loss

A

True

47
Q

Surprisingly, prolonged use of some AHA formulations actually make stratum corneum more resistant to potentially irritating substances such as detergents

A

True

48
Q

Compared to AHA, preliminary studies of PHA have been shown to have equivalent anti-aging effects

A

True

49
Q

Both AHA and PHA are well tolerated, but patients report associated burning and stinging with AHA products

A

True

50
Q

Glycolic acid peels can be used for dermatoheliosis by starting at a low % Glycolic acid and then gradually increasing this on an individual basis as tolerated

A

True

51
Q

Patients with oily skin are less reactive to Glycolic acid peels

A

True

52
Q

Patients with excessive sun-induced or environmental damage are more sensitive to Glycolic acid peels

A

True

53
Q

Patients are encouraged to repeat a previous treatment regimen (% AHA and duration) if they experienced excessive irritation of peeling with the last treatment

A

True

54
Q

Some authors believe that patients who used a combination therapy of Tretinoin (retinoid) and Glycolic acid (AHA) have better acne control than with either agent alone

A

True (Glycolic acid aids in comedone extrusion whilst Tretinoin prevents new comedone formation) - therefore some dermatologists prescribe a Tretinoin at night and an appropriate AHA for the morning

55
Q

Monthly superficial AHA (Glycolic acid) peels are usually added to the management of acne as Glycolic acid helps to resolve non-inflammatory, superficial inflammatory and nodulocystic acne lesions

A

True

56
Q

When using AHA peels in conjunction with Tretinoin for acne, physicians must be aware that Tretinoin increases the depth of treatment and the resultant exfoliation

A

True (use a more superficial peel instead)

57
Q

AHA (Glycolic acid 8% lotion) is also reported to be effective in treating pseudofolliculitis barbae, resulting in reduction of lesions with little irritation

A

True

58
Q

AHA (Glycolic acid) peels reduce the inflammation in Rosacea

A

True

59
Q

Although topical retinoids have been used for Rosacea, they can produce excessive irritation and exacerbate the telengiectatic component, which is in contrast to AHA which do not promote angiogenesis

A

True

60
Q

AHA may prevent attachment of the Demodex mite in the follicles of Rosacea patients through the AHA effect on corneocyte adhesion

A

True

61
Q

The low pH of AHA (Glycolic acids) may deplete bacterial nutrients and reduce the presence of viable pathogens in Rosacea patients

A

True

62
Q

For patients with papulopustular Rosacea, AHA (Glycolic acid) peels may be used on a daily basis and in the office setting similar to that described for acne vulgaris

A

True

63
Q

Glycolic acid (AHA) may be used in combination with other bleaching agents such as hydroquinone to enhance each other’s penetrance and yielding a better therapeutic response for management of pigmentary disorders

A

True

64
Q

Glycolic acid (AHA) may be combined with ‘Kligman regimen’ (hydroquinone, Tretinoin, topical corticosteroid) for greater skin lightening effects in pigmentary disorders

A

True

65
Q

AHA (Glycolic acid) peels are effective and safe in medium to dark skinned individuals but the % Glycolic acid and the peeling time must be increased with caution due to the risks of more chemical irritancy and possible post-inflammatory hyperpigmentation

A

True

66
Q

Chemical peeling agents used in the office setting contain AHA concentrations from 20-70%

A

True

67
Q

The topical efficacy of an AHA formulation depends on its bioavailability concentration and the vehicle used

A

True

68
Q

For topical treatments, penetration of the stratum corneum is the major limiting factor determining the free AHA concentration in the epidermis and dermis

A

True

69
Q

For AHA formulations, the closer the pH is to neutral (pH7), the less the irritation there is to the skin

A

True (AHA can be neutralised with an inorganic alkali or organic base to raise the pH, making the formulation less irritating to the skin)

70
Q

The AHA can also be buffered to create a compound that resists pH changes when an acid or alkali is added in order to maintain a range of pH i.e between 2.8 and 4.8, although this reduces the free acid levels and efficacy of the AHA preparation

A

True (buffering is not synonymous to neutralisation of an AHA formulation)

71
Q

The bioavailability of AHA (free acid levels) can be calculated from both the pH of the preparation and the concentration of the AHA

A

True

72
Q

Because glycolic acid is water soluble, most Glycolic acid in the water phase is in direct contact with stratum corneum when applied topically

A

True (hence vehicle plays a role in absorption)

73
Q

Glycerin (used in vehicles) has a strong affinity for AHA and because Glycerin cannot substantially penetrate the stratum corneum, it reduces the AHA absorption

A

True

74
Q

Propylene glycol in the vehicle can enhance the penetration of AHA by modifying the permeability of the stratum corneum

A

True

75
Q

When selecting a topical therapy with AHA, the physician should choose a vehicle that enhances drug delivery, is non-irritating and promotes patients compliance

A

True

76
Q

There is clearly an inverse relationship between the pH of AHA preparations and their potential for skin irritation

A

True (higher the pH, lower potential for skin irritation)

77
Q

Skin irritation depends on the pH of the AHA formulation and not the AHA %, as the pH of the AHA formulation is lowered, the potential for skin irritation is increased

A

True (there is an inverse relationship between pH of AHA and their potential for skin irritation)

78
Q

As the pH of AHA formulation is nearer to neutrality at 4.4, the cutaneous irritation dropped off markedly

A

True

79
Q

The epidermal effects such as thinning of the stratum corneum and thickening of the viable epidermis is noted when patients are treated with a Glycolic acid product with pH 3.8 but the efficacy of Glycolic acid diminishes when the pH approaches 4.4

A

True

80
Q

The ideal pH for an AHA formulation is 3.8

A

True (lower % AHA also produces significant dermal effects at pH 3.8 + efficacy of Glycolic acid on epidermal effects diminishes the pH approaches 4.4)

81
Q

More rapid absorption and subsequent irritation from AHA occurred at lower pH levels

A

True

82
Q

AHA may cause burning

A

True

83
Q

AHA may cause dermatitis

A

True

84
Q

AHA may cause swelling

A

True

85
Q

AHA may cause skin discolouration

A

True

86
Q

AHA may cause blistering

A

True

87
Q

AHA may cause peeling

A

True

88
Q

AHA may cause itching

A

True

89
Q

The most common adverse effect from AHA use is irritant contact dermatitis

A

True

90
Q

Irritant contact dermatitis from AHA can be managed by reducing the AHA concentration, altering the application schedule or increasing the pH of the product

A

True

91
Q

Most patients experience mild erythema, burning, stinging for several minutes to a few hours after a superficial AHA peel

A

True

92
Q

If the reaction from a superficial AHA peel is more severe or prolonged such as scaling, crusting, or blistering; application of a topical corticosteroid can be helpful

A

True

93
Q

Pigmentary disturbances may result from a AHA chemical peel and necessitate additional treatment

A

True

94
Q

All skin types are susceptible to hypopigmentation following a deep AHA chemical peel but this is rare

A

True

95
Q

Hyperpigmentary problems from AHA peels are more often encountered in dark skinned individuals and usually respond to treatment with Tretinoin and/or bleaching creams

A

True (proper photoprotection is recommended for several weeks following a peel)

96
Q

Larger molecular weight AHA (Malic acid, citric acid) tend to remain on the skin surface much longer, therefore producing more of an epidermal effect as the stratum corneum resists penetration of these compounds

A

True (these larger molecular weight AHA also result in less stinging and burning than the lower molecular weight AHA)

97
Q

HSV infection can rarely be triggered from a AHA peel due to chemical and/or inflammatory trauma, therefore prophylactic acyclovir, Valacyclovir or Famciclovir can be used to minimise postoperative herpetic infections in patients who are prone to such outbreaks

A

True

98
Q

Short term topical application of Glycolic acid increases the skin’s photosensitivity

A

True (Unknown mechanism, advisable for patients to wear adequate sunscreen when using AHA)

99
Q

One possible explanation for AHA-induced photosensitivity is that UVR is transmitted through normally moisturised skin than through dry skin as dry skin scatters or reflects UVR

A

True (AHA reduces stratum corneum thickness/hyperkeratosis and remodels the epidermis)

100
Q

The tumour prevention effects of AHA may be attributed to the removal of photodamaged keratinocytes

A

True