Therapeutic Considerations in Pediatric Dermatology

General Principles - Little Skins, Big Care

• Pediatric skin characteristics:
  • ↑ Surface area to volume ratio.
  • Thinner stratum corneum.
  • Immature skin barrier function (↓ lipids, altered pH).
  • Developing microbiome.
• Therapeutic implications:
  • ↑ Percutaneous absorption of topical agents.
  • ↑ Risk of systemic toxicity from topicals (e.g., corticosteroids, lindane).
  • ↑ Transepidermal water loss (TEWL).
• Dosing principles:
  • Weight-based (mg/kg) is most common.
  • Body Surface Area (BSA) for potent/narrow therapeutic index drugs (e.g., methotrexate).

⭐ Topical corticosteroids can cause significant adrenal suppression in infants due to higher systemic absorption per unit body surface area.

Topical Therapies - Skin-Deep Solutions

• Topical Corticosteroids (TCS): Potency Classes I (Superpotent) to VII (Least potent).
  • Selection: Age (child: low potency), site (face/folds: low potency), severity of dermatosis.
  • Duration: Limit potent TCS to <2-4 weeks; use lowest effective potency for shortest duration.
  • Side effects: Skin atrophy, striae, telangiectasia, tachyphylaxis, systemic absorption (esp. infants, large areas, occlusion).
  • 📌 TCS Potency: Class I (Superpotent) > II > III > IV > V > VI > VII (Least potent).
• Topical Calcineurin Inhibitors (TCIs): Tacrolimus (0.03%, 0.1%), Pimecrolimus (1%).
  • Mechanism: Inhibit calcineurin → ↓ T-cell activation & inflammatory cytokines. No skin atrophy.
  • Indications: Atopic dermatitis (AD) - 2nd line, esp. sensitive areas (face, eyelids, intertriginous).
  • ⚠️ Black Box Warning: Potential long-term risk of rare malignancies; use as per guidelines.
• Emollients: Cornerstone of pediatric dermatology.
  • Importance: Restore skin barrier, hydrate, reduce xerosis, steroid-sparing.
  • Types: Ointments (most occlusive) > Creams > Lotions (least occlusive).
  • Frequency: Apply liberally & frequently, esp. within 3 minutes post-bathing (Soak and Seal).
• Other Topicals (Brief):
  • Antifungals: e.g., Clotrimazole, Miconazole for tinea, candidiasis.
  • Antibacterials: e.g., Mupirocin for impetigo, Fusidic acid.
  • Keratolytics: e.g., Salicylic acid, Urea (use cautiously in young children due to absorption risk).

⭐ Tacrolimus ointment does not cause skin atrophy, making it a preferred option for long-term intermittent use on sensitive skin areas like the face and flexures in atopic dermatitis, unlike topical corticosteroids.

Systemic Therapies - Inside-Out Healing

• Oral Antihistamines:
  • Sedating (e.g., hydroxyzine): for intense pruritus, urticaria; use with caution in young children.
  • Non-sedating (e.g., cetirizine, loratadine): preferred for daytime relief in chronic conditions.
• Oral Antibiotics: For bacterial skin infections like impetigo, cellulitis.
  • Common: Cephalexin, Amoxicillin-clavulanate.
  • Duration: Typically 7-14 days.
• Oral Antifungals:
  • Fluconazole: For candidiasis, tinea versicolor.
  • Griseofulvin: Gold standard for tinea capitis (requires fatty meal). 📌 "Greasy griseo for hair"
  • Monitoring: LFTs with prolonged use (e.g., >4 weeks).
• Systemic Corticosteroids/Immunosuppressants (e.g., Prednisolone):
  • Reserved for severe, refractory conditions: e.g., severe atopic dermatitis, psoriasis, vasculitis.

⭐ Griseofulvin, crucial for tinea capitis, must be taken with a fatty meal to significantly enhance its absorption and efficacy.

Condition Spotlights - Tiny Patient Tactics

Atopic Dermatitis (AD) eczematous inflammation

• Step-care approach:

⭐ > Topical corticosteroids for atopic dermatitis should be chosen based on potency and location; low potency (e.g., hydrocortisone **1%**) for face/intertriginous areas.

Diaper Dermatitis 👶

• Irritant: Erythema, spares folds.
  • Tx: Barrier creams (zinc oxide), frequent diaper changes, air exposure.
• Candidal: Beefy red plaques, satellite pustules, involves folds.
  • Tx: Topical antifungals (nystatin, clotrimazole) + barrier.

Molluscum Contagiosum (MC) 🦠

• Poxvirus; umbilicated papules.
• Options:
  • Watchful waiting (spontaneous resolution).
  • Destructive: Cryotherapy, curettage.
  • Chemical: Cantharidin (⚠️ blistering, avoid face/genitals).
  • Immunomodulatory: Imiquimod 5% cream. 📌 Mnemonic: "Molluscum Mountain" - Watch, Freeze, Burn, or Boost (Immunity).

High‑Yield Points - ⚡ Biggest Takeaways

• Topical corticosteroids: Use lowest effective potency; be aware of risks like skin atrophy and HPA axis suppression.
• Emollients: Cornerstone for atopic dermatitis and dry skin; apply frequently and liberally.
• Systemic absorption of topical drugs is higher in children due to ↑ body surface area to volume ratio and thinner stratum corneum.
• Tetracyclines (e.g., doxycycline) are contraindicated in children <8 years due to dental staining and potential bone growth inhibition.
• Isotretinoin use requires strict teratogenicity precautions and monitoring of lipids and liver function tests.
• Griseofulvin for tinea capitis is better absorbed with a fatty meal.
• Permethrin 5% cream is first-line for scabies; treat all household contacts simultaneously.