Skin conditions, management

Question 1

The British Association of Dermatologists list of preferred unlicensed dermatological preparations (specials) is available at:

Answer 1

https://www.bad.org.uk/guidelines-and-standards/access-to-medicines/.

Question 2

Both vehicle and active ingredients are important in the treatment of skin conditions; the vehicle alone may have more than a…

Answer 2

mere placebo effect.

Question 3

The vehicle affects

Answer 3

1. the degree of hydration of the skin
2. has a mild anti-inflammatory effect and 3. aids the penetration of active drug.

Question 4

What are applications?

Answer 4

Usually viscous solutions, emulsions, or suspensions for application to the skin (including the scalp) or nails.

Question 5

What are collodions? How are they applied?

Answer 5

Hint:Collodion is a flammable syrupy solution of nitrocellulose, ether and alcohol. It is used as a coating solution in surgical dressings or more.
They are painted on the skin and allowed to dry to leave a flexible film over the site of application.

Question 6

What are creams?

Answer 6

Emulsions of oil and water and are generally well absorbed into the skin.

Question 7

What might a cream contain?

Answer 7

An antimicrobial preservative unless the active ingredient or basis is intrinsically bactericidal and fungicidal.

Question 8

What is more preferred, creams or ointments?

Answer 8

Generally, creams are cosmetically more acceptable than ointments because they are less greasy and easier to apply.

Question 9

What do gels consist of?

Answer 9

Active ingredients in suitable hydrophilic or hydrophobic bases; they generally have a high water content. Gels are particularly suitable for application to the face and scalp.

Question 10

When might lotions be favoured over creams and ointments?

Answer 10

Lotions have a cooling effect and may be preferred to ointments or creams for application over a hairy area. Lotions in alcoholic basis can sting if used on broken skin.

Question 11

What are shake lotions and what might they contain?

Answer 11

1. Shake lotion is an aqueous suspension of powders. Hence, such lotions require shaking before each application.
2. Shake lotions (such as calamine lotion) contain insoluble powders which leave a deposit on the skin surface.

Question 12

What are ointments

Answer 12

Greasy preparations which are normally anhydrous and insoluble in water, and are more occlusive than creams.

Question 13

What are ointments particularly suitable for?

Answer 13

Chronic, dry lesions.

Question 14

The most commonly used ointment bases consist of…

Answer 14

Soft paraffin or a combination of soft, liquid, and hard paraffin.

Question 15

Can ointments have hydrophilic or lipophilic properties?

Answer 15

Both. They may have occlusive properties on the skin surface, encourage hydration, and also be miscible with water; they often have a mild anti-inflammatory effect.

Question 16

What do water-soluble ointments contain that helps with removal?

Answer 16

Water-soluble ointments contain macrogols which are freely soluble in water and are therefore readily washed off; they have a limited but useful role where ready removal is desirable.

Question 17

Define pastes and what they’re used for:

Answer 17

Pastes are stiff preparations containing a high proportion of finely powdered solids such as zinc oxide and starch suspended in an ointment. They are used for circumscribed lesions such as those which occur in lichen simplex, chronic eczema, or psoriasis.

Question 18

Occlusive ingredients sit on the skin as a barrier rather than emollient ingredients that can influence how the skin cells function. Would you say pastes are more or less occlusive than ointments?

Answer 18

They are less occlusive than ointments and can be used to protect inflamed, lichenified, or excoriated skin.

Question 19

How are dusting powders used?

Answer 19

Dusting powders are used only rarely. They reduce friction between opposing skin surfaces.

Question 20

Should dusting powders be applied to moist areas?

Answer 20

No because they can cake and abrade the skin.

Question 21

What is talc? Does it absorb moisture?

Answer 21

Talc is a lubricant but it does not absorb moisture; it can cause respiratory irritation

Question 22

How does starch differ from talc?

Answer 22

Starch is less lubricant but absorbs water.

Question 23

Should creams and ointments be diluted?

Answer 23

The BP directs that creams and ointments should not normally be diluted but that should dilution be necessary care should be taken, in particular, to prevent microbial contamination.

Question 24

If creams and ointment are diluted, how should this be achieved?

Answer 24

1. The appropriate diluent should be used
2. Heating should be avoided during mixing
3. Careful of excessive dilution as this may affect the stability of some creams.
4. Diluted creams should normally be used within 2 weeks of preparation.

Question 25

What are the suitable quantities of dermatological preparations to be prescribed for the face?

Answer 25

Creams and Ointments: 15–30 g Lotions: 100 mL These amounts are usually suitable for an adult for twice daily application for 1 week. The recommendations do not apply to corticosteroid preparations. For suitable quantities of corticosteroid preparations, see relevant table.

Question 26

What are the suitable quantities of dermatological preparations to be prescribed for both hands?

Answer 26

Creams and Ointments: 25-50 g Lotions: 200 mL These amounts are usually suitable for an adult for twice daily application for 1 week. The recommendations do not apply to corticosteroid preparations. For suitable quantities of corticosteroid preparations, see relevant table.

Question 27

What are the suitable quantities of dermatological preparations to be prescribed for the scalp?

Answer 27

Creams and Ointments: 50–100 g Lotions: 200 mL These amounts are usually suitable for an adult for twice daily application for 1 week. The recommendations do not apply to corticosteroid preparations. For suitable quantities of corticosteroid preparations, see relevant table.

Question 28

Are these amounts suitable for children?

Answer 28

These amounts are usually suitable for children 12-18 years for twice daily application for 1 week; smaller quantities will be required for children under 12 years. These recommendations do not apply to corticosteroid preparations.

Question 29

What are the suitable quantities of dermatological preparations to be prescribed for both arms or both legs?

Answer 29

Creams and ointments: 100–200 g Lotions: 200mL These amounts are usually suitable for an adult for twice daily application for 1 week. The recommendations do not apply to corticosteroid preparations. For suitable quantities of corticosteroid preparations, see relevant table.

Question 30

What are the suitable quantities of dermatological preparations to be prescribed for the trunk?

Answer 30

Creams and ointments: 400 g Lotions: 500 mL These amounts are usually suitable for an adult for twice daily application for 1 week. The recommendations do not apply to corticosteroid preparations. For suitable quantities of corticosteroid preparations, see relevant table.

Question 31

What are the suitable quantities of dermatological preparations to be prescribed for groins and genitalia?

Answer 31

Creams and ointments: 15–25 g Lotions: 100mL These amounts are usually suitable for an adult for twice daily application for 1 week. The recommendations do not apply to corticosteroid preparations. For suitable quantities of corticosteroid preparations, see relevant table.

Question 32

Do excipients in topical products cause problems?

Answer 32

Rarely

Question 33

How can you find out if an excipient i topical products cause problems?

Answer 33

If a patch test indicates allergy to an excipient, products containing the substance should be avoided.

Question 34

The following excipients in topical preparations are associated, rarely, with sensitisation; the presence of these excipients is indicated in the entries for topical products.

Answer 34

Beeswax Benzyl alcohol Butylated hydroxyanisole Butylated hydroxytoluene Cetostearyl alcohol (including cetyl and stearyl alcohol) Chlorocresol Edetic acid (EDTA) Ethylenediamine Fragrances Hydroxybenzoates (parabens) Imidurea Isopropyl palmitate N-(3-Chloroallyl)hexaminium chloride (quaternium 15) Polysorbates Propylene glycol Sodium metabisulfite Sorbic acid Wool fat and related substances including lanolin (purified versions of wool fat have reduced the problem)

Question 35

With topical preparations, what must be considered for neonates and why?

Answer 35

Caution is required when prescribing for neonates: their large BSA in relation to body mass increases susceptibility to toxicity from systemic absorption of substances applied to the skin.

Question 36

Should topical preparations containing potentially sensitising substances such as corticosteroids, aminoglycosides, iodine, and parasiticidal drugs be avoided?

Answer 36

Yes.

Question 37

Should preparations containing alcohol be avoided?

Answer 37

Yes because they can dehydrate the skin, cause pain if applied to raw areas, and the alcohol can cause necrosis.

Question 38

What needs to be considered in preterm neonates?

Answer 38

In preterm neonates, the skin is more fragile and offers a poor barrier, especially in the first fortnight after birth.

Question 39

What needs to be considered in preterm infants?

Answer 39

Preterm infants, especially if below 32 weeks corrected gestational age, may also require special measures to maintain skin hydration.