DERMATOLOGY Flashcards
(29 cards)
What is dermatitis?
Inflammation of the dermis and epidermis. Presentation may include erythema, vesicles, and pruritus. History is crucial for diagnosis.
Differentiate types of dermatitis.
Atopic: IgE-mediated, barrier dysfunction
Contact allergic: T-cell mediated
Irritant: Non-allergic, inflammatory
What is the non-pharmacological management of atopic dermatitis?
Frequent moisturisers (post-bath)
pH-neutral, fragrance-free cleansers
Avoid triggers
Wet-wrap therapy during flare-ups
Key moisturiser excipients?
Humectants (glycerin), occlusives (petrolatum), emollients (lanolin)
How do Topical CorticoSteroids work in dermatitis?
↓ Leukocyte infiltration
↓ Macrophage/APC function
↓ Prostaglandin and leukotriene production
Vasoconstriction via ↓ histamine release
TCS safety concerns?
Systemic absorption minimal
Caution in children due to high BSA:weight
Side effects: skin thinning, striae, telangiectasia
How to use TCS safely in children?
Fingertip unit (FTU) dosing method:
1 FTU = 2 adult hand areas
What are calcineurin inhibitors?
Tacrolimus (Protopic®), Pimecrolimus (Elidel®)
MOA: Inhibit T-lymphocyte activation, mast cell degranulation
AE: Burning, pruritus, erythema
Used for sensitive skin, steroid intolerance
What causes acne?
Multifactorial:
↑ sebum via androgens
Hyperkeratinisation
C. acnes colonisation
Inflammatory cytokines (IL-1β, TNFα)
Non-pharmacological acne management?
Twice daily cleansing (oil-free)
Avoid occlusive cosmetics
Avoid picking
Diet: Cut processed food, chocolate
Benzoyl peroxide MOA and AE?
Kills C. acnes
AE: Redness, scaling, bleaching
Azelaic acid?
↓ C. acnes
↓ DHT conversion
AE: Redness, dryness, delayed onset (6–8 weeks)
Retinoid MOA and safety?
Act on RAR/RXR → normalize keratinization
AE: Irritation, photosensitivity, teratogenic
Drugs: Tretinoin (Retin-A®), adapalene (Differin®)
Topical antibiotics?
Clindamycin, erythromycin (not monotherapy)
Combine with benzoyl peroxide (e.g., Clindoxyl®)
When to use systemic antibiotics for acne?
For moderate-severe acne.
Tetracyclines (doxycycline): inhibit C. acnes, ↓ inflammation
AE: GI upset, hyperpigmentation, contraindicated <8yrs or in pregnancy
Systemic retinoids (Isotretinoin)?
↓ Sebaceous gland size
AE: Dry skin, LFT ↑, teratogenicity
Monitor lipids, LFTs, pregnancy
Oral contraceptives in acne?
↓ Androgens → ↓ sebum
Use low-androgenicity pills e.g. Diane-35®, Ginette®, Angeliq®
What causes superficial mycoses?
Dermatophytes: Trichophyton, Microsporum, Epidermophyton
Risk factors: Maceration, shared items, intertriginous folds
Classical signs of skin mycoses?
Central clearing with red, scaly “active border”
Imidazoles?
Broad activity: dermatophytes + Candida
MOA: Inhibit ergosterol via CYP450 inhibition
Terbinafine (topical)?
Allylamine: inhibits squalene epoxidase
Used in tinea, Malassezia
Selenium sulphide?
Mild antifungal
↓ corneocyte production
For seborrheic dermatitis, tinea capitis
When to use oral antifungals?
For resistant or extensive infections:
Fluconazole: CNS penetration, few interactions
Itraconazole: Lipophilic, food boosts absorption
Terbinafine: For skin/nail; LFT monitoring
Griseofulvin: Fungistatic, binds keratin; delayed effect
How to treat fungal nail infections? (onychomycosis)
Topical: Amorolfine (Loceryl®) – poor penetration, file nail first
Oral: Terbinafine, Itraconazole
Treat fingernails = 6 weeks; toenails = 12 weeks
