Topical Treatments

Question 1

What are bases or vehicles

Answer 1

The substance that the active drug is dissolved in when applied to the skin

Question 2

Name 6 examples of bases/vehicles

Answer 2

Creams, ointments, lotion, gels, pastes, foams

Question 3

Describe the key features of creams

Answer 3

WHAT?
- Semi sold emulsification of oil in water
- Contains emulsifier & preservative
- High water content

USES
- Cools & moisturises the skin

BENEFITS
- Non-greasy, easy to apply & cosmetically acceptable

Question 4

Describe the key features of ointments

Answer 4

WHAT?
- Semi solid grease/ oil (soft paraffin)
- Doesn’t contain preservatives
- High lipid content

USES
- Are occlusive & limit transdermal water loss

DISADVANTAGES
- Greasy & less cosmetically acceptable

Question 5

Describe the key features of lotions

Answer 5

WHAT?
- Liquid formulations of medications
- Medication suspended in alcohol or water

USES
- Treats dry, hair-bearing areas such as the scalp

DISADVANTAGES
- Suspension in alcohol can cause stinging

Question 6

Describe the key features of gels

Answer 6

WHAT?
- Semi solid thickened aqueous lotions/solutions
- Contains high molecular weight polymers e.g methylcellulose

USES
- Used to treat hair-bearing areas and the face

Question 7

Describe the key features of pastes

Answer 7

WHAT?
- Semi solid finely powdered material e.g. zinc

USES
- Cool and hydrate the skin, often used in cooling bandages

DISADVANTAGES
- Stiff, greasy, difficult to apply

Question 8

Describe the key features of foams

Answer 8

WHAT?
- Colloid with two – three phases
- Usually hydrophilic liquid in continuous phase
- With foaming agent dispersed in gaseous phase

BENEFITS
- Increased penetration of active agent
-Can easily spread over large areas
- Not greasy or oily

Question 9

What are emollients

Answer 9

Any ointment/cream/lotion/gel
That enhances rehydration of epidermis

Question 10

Emollient uses

Answer 10

• Dry/scaly skin conditions e.g. eczema
• Certain emollients (e.g. emulsifying ointments) can be used as soap substitutes

Question 11

What topical treatments are a fire risk

Answer 11

Paraffin-based treatments (ointments)

Question 12

Emollients containing what substance should not be left on

Answer 12

SLS

Question 13

Why does certain emollients contain urea

Answer 13

urea attracts and holds water in the stratum corneum which compensates for the reduced levels of natural moisturising factor (NMF)

Question 14

What is wet wrap therapy

Answer 14

Liberal emollients (and topical steroids if required) are applied and then covered with two layers of tubifast bandage, the first wet and the other dry

Question 15

When is wet wrap therapy used

Answer 15

Used for very dry (xerotic) skin
Soothes the skin, introduces moisture and protects from damage caused by scratching

Question 16

What are the effects of topical corticosteroids

Answer 16

Anti-inflammatory, immunosuppressant & vasoconstricting effects plus anti-proliferating action upon keratinocytes and fibroblasts

Question 17

What topical steroids are there

Answer 17

Mild - hydrocortisone 1%
Moderate - Modrasone clobetasone butyrate 0.05%
Potent - Mometasone betamethasone valerate 0.1%
Very potent - Clobetasol proprionate 0.05%

Question 18

When are topical corticosteroids used

Answer 18

Inflammatory conditions
- Particularly atopic eczema and contact dermatitis
- Psoriasis - beware rebound or triggering pustular psoriasis
- Generally used when simple emollients become ineffective
- Non-infective inflammatory dermatoses e.g. lichen planus
- Keloid scars (intralesional or tape)

Question 19

Topical steroid reversible local side effects

Answer 19

• Acneiform eruptions
• Perioral dermatitis
• Can mask fungal infections
• ‘rebound’ psoriasis
• tachyphylaxis
• Contact allergy to hydrocortisone
• Steroid rosacea - facial flushing, telangiectasia, inflammatory lesions

Question 20

Topical steroids systemic absorption side effects

Answer 20

• Suppression of HPA axis
• Cushing’s disease (very rare)
• Growth retardation (very rare)

Question 21

Topical steroids permanent side effects

Answer 21

• Glaucoma and cataract
• Hirsutism (male pattern hair distribution in women)
• Striae (stretch marks)
• Thinned epidermis (atrophy) → easy bruising, purpura
• Multiple telangiectasia (dilated superficial blood vessels)

Question 22

What factors affect the penetration & potency of topical steroids

Answer 22

• Body site e.g. thickness of stratum corneum
• Skin - permeability & Occlusion
• Specific drug - formulation & concentration
• Vehicle - affects potency and affects compliance

Question 23

When would you use cream vs ointment vs lotion steroids

Answer 23

• Moist or weeping lesion - creams
• Dry, lichenified, scaly lesions - ointments
• Large area, hair bearing areas, exudative lesions - lotions

Question 24

What can be added to topical steroids to increase penetration

Answer 24

Urea, salicylic acid

Question 25

When might occlusive polythene or hydrocolloid dressings be used when applying topical steroids & what benefits and risks does it have

Answer 25

• Only used under supervision on a short term basis
• Only on areas of very thick skin (e.g. palms and soles)
• Increases absorption but also increases side effects