Derm summary 4

Question 1

What are the characteristics and uses of creams in dermatology?

Answer 1

Type: Emulsions (usually oil-in-water)
Properties: Contain water, need preservatives
Texture: Light, easy to spread
Absorption: Moderate; good for moist or weeping lesions
Use: Non-greasy feel, moderate absorption
Examples: Hydrocortisone cream, Clotrimazole cream

Question 2

What are the characteristics and uses of ointments in dermatology?

Answer 2

Type: Anhydrous, greasy, occlusive
Properties: No preservatives needed
Texture: Thick, greasy
Absorption: Excellent; enhances penetration
Use: Dry, scaly, lichenified skin; overnight
Examples: White soft paraffin, Betnovate ointment, Diprosalic ointment

Question 3

What are the characteristics and uses of lotions in dermatology?

Answer 3

Types: Emulsions (e.g., Locoid Crelo), Suspensions (e.g., Calamine), Solutions (e.g., Betnovate scalp)
Properties: Low viscosity, runny, fast-drying
Use: Large or hairy areas, weeping/exudative lesions
Examples: Calamine lotion, steroid scalp lotions

Question 4

What are the characteristics and uses of gels in dermatology?

Answer 4

Type: Water-based, semisolid
Agents: Carbomers, xanthan gum, cellulose derivatives
Texture: Non-greasy, cooling
Absorption: Moderate to good
Use: Oily skin, hair-bearing areas, patient preference
Examples: Clindamycin gel, Ibuprofen gel, Metronidazole gel

Question 5

What are common additional ingredients in topical formulations and their functions?

Answer 5

Preservatives: prevent microbial growth (e.g., parabens)
Emulsifiers: stabilise emulsions (e.g., cetearyl alcohol)
Penetration enhancers: improve drug delivery (e.g., propylene glycol)
Vehicles/Bases: affect delivery and formulation (e.g., paraffin)

Question 6

Which topical base is recommended for different lesion types?

Answer 6

Dry lesions: Ointments
Moist/weeping: Creams or gels
Exudative/wet: Lotions or gels
Hairy areas: Lotions, gels

Question 7

What counselling tips should be given when using topical treatments?

Answer 7

1. Apply emollients generously (e.g., 500g/week for eczema)
2. Apply in direction of hair growth
3. Leave 30-minute gap between emollient and steroid
4. Warn about: slipping, fire risk (paraffin), contamination risks