Topical Corticosteroids
Classified into 7 potency classes (Class I = most potent, Class VII = least potent). Choose based on diagnosis, body site, and patient age.
| Class | Potency | Examples | Use Cases |
|---|---|---|---|
| I | Super high | Clobetasol 0.05%, halobetasol 0.05% | Psoriasis, lichen sclerosus, discoid lupus; avoid face/skin folds/genitals; max 2 weeks |
| IIโIII | High | Fluocinonide 0.05%, betamethasone dipropionate 0.05% | Severe eczema, psoriasis on thick skin; avoid face >2 weeks |
| IVโV | Medium | Triamcinolone 0.1%, fluticasone 0.05%, betamethasone valerate 0.1% | Moderate atopic dermatitis, contact dermatitis on trunk/extremities |
| VI | Low | Desonide 0.05%, alclometasone 0.05% | Face, intertriginous areas, children, mild dermatitis |
| VII | Least | Hydrocortisone 1%, 2.5% | Face, diaper area, mild inflammation; OTC |
Boards PearlSide effects increase with potency and duration: skin atrophy, striae, telangiectasias, hypopigmentation, perioral dermatitis, HPA axis suppression (especially in children). Face/genitals/intertriginous areas: Class VIโVII only. NEVER use high-potency on face long-term.
Practical TipsFingertip unit (FTU) = 0.5g, covers 2 palmar areas. Ointments more potent than creams (better penetration). Wet wrap technique increases absorption. Taper gradually after extended high-potency use to avoid rebound.
Topical Retinoids
Vitamin A derivatives โ bind retinoic acid receptors โ normalize keratinocyte differentiation, reduce comedone formation, anti-inflammatory
| Drug | Generation | Indications | Notes |
|---|---|---|---|
| Tretinoin (Retin-A) | 1st gen | Acne vulgaris, photoaging, melasma | Most studied; apply at night; initial irritation, purging (4โ8 weeks); photosensitivity |
| Adapalene (Differin) | 3rd gen | Acne (OTC 0.1%, Rx 0.3%) | Less irritating than tretinoin; gel preferred; good for sensitive skin |
| Tazarotene (Tazorac) | 3rd gen acetylenic | Acne, psoriasis | Most potent topical; most irritating; CI in pregnancy (teratogenic) |
| Trifarotene (Aklief) | 4th gen | Acne (face + trunk) | RAR-ฮณ selective; good for truncal acne |
Key Retinoid RuleApply pea-sized amount to clean, dry skin at night. Start every other night to build tolerance. "Start low, go slow." All topical retinoids: avoid in pregnancy (teratogenic risk โ tazarotene is Category X).
Isotretinoin (Accutane) & iPLEDGE
Mechanism
Oral retinoid โ reduces sebum production (โ sebaceous gland size), normalizes follicular epithelial desquamation, anti-inflammatory, anti-comedogenic
Indications
- Severe nodular/cystic acne unresponsive to antibiotics
- Moderate acne causing scarring
- Acne causing significant psychological distress
- Gram-negative folliculitis
iPLEDGE Program (REMS)
iPLEDGE Requirements
- Monthly prescriptions only; 30-day supply max
- Females with reproductive potential: 2 forms of contraception starting 1 month BEFORE, DURING, and 1 month AFTER treatment
- 2 negative pregnancy tests before starting (1 in office, 1 at certified lab)
- Monthly pregnancy tests during treatment
- All patients: monthly counseling, blood work (lipids, LFTs), mental health monitoring
Side Effects & Monitoring
| Side Effect | Notes |
|---|---|
| Teratogenicity | Highest teratogenic risk of any drug; Category X; causes craniofacial, cardiac, CNS defects |
| Mucocutaneous | Cheilitis (90%), dry skin/eyes/mouth; epistaxis; alopecia โ use emollients, lip balm |
| Hypertriglyceridemia | Monitor lipids monthly; discontinue if TG >800 mg/dL (pancreatitis risk) |
| Elevated LFTs | Usually mild and reversible; monitor monthly |
| Mood/depression | Controversial; monitor for mood changes, suicidal ideation; inform patients |
| Night blindness | Decreased rhodopsin; advise caution while driving at night |
| Bone effects | Premature epiphyseal closure in children/adolescents; arthralgia, myalgia |
| Pseudotumor cerebri | Increased ICP; headache, visual changes; DO NOT combine with tetracyclines (synergistic risk) |
Boards PearlDo NOT combine isotretinoin + tetracyclines (doxycycline/minocycline) = โ pseudotumor cerebri risk. Do NOT donate blood during treatment + 1 month after (teratogenic risk to pregnant recipients). Course: typically 4โ6 months; total cumulative dose 120โ150 mg/kg determines remission rate.
Biologics for Dermatologic Conditions
Psoriasis Biologics
| Drug | Target | Class | Notes |
|---|---|---|---|
| Adalimumab (Humira) | TNF-ฮฑ | Anti-TNF | Also approved for PsA, hidradenitis suppurativa; TB reactivation risk; hepatitis B reactivation |
| Etanercept (Enbrel) | TNF-ฮฑ/ฮฒ | Anti-TNF fusion | SQ injection; less immunogenic than adalimumab; can use in children โฅ4yo |
| Secukinumab (Cosentyx) | IL-17A | Anti-IL-17A | Also for PsA, ankylosing spondylitis; caution in IBD (may worsen Crohn's) |
| Ixekizumab (Taltz) | IL-17A | Anti-IL-17A | Similar to secukinumab; monthly dosing after loading |
| Ustekinumab (Stelara) | IL-12/23 (p40) | Anti-IL-12/23 | Q12 week dosing; also Crohn's (safer in IBD patients); weight-based dosing |
| Guselkumab (Tremfya) | IL-23 (p19) | Anti-IL-23 | Highly selective IL-23; Q8 week maintenance; high PASI response rates |
| Risankizumab (Skyrizi) | IL-23 (p19) | Anti-IL-23 | Q12 week maintenance; among highest efficacy rates (PASI 90/100) |
Screening Before BiologicsTB (PPD or IGRA), hepatitis B/C serology, CBC, CMP, HIV. Treat latent TB before starting. Update vaccines (live vaccines contraindicated while on biologics). Stop before surgery (typically 1 dosing cycle).
Atopic Dermatitis Biologics
| Drug | Target | Notes |
|---|---|---|
| Dupilumab (Dupixent) | IL-4Rฮฑ (blocks IL-4 + IL-13) | First-line biologic for mod-severe atopic dermatitis; also approved for asthma, CRS with polyps, EoE, prurigo nodularis; SQ Q2 weeks; injection site reactions, conjunctivitis |
| Tralokinumab (Adbry) | IL-13 | Q2 week SQ; similar efficacy to dupilumab; fewer conjunctivitis reports |
| Lebrikizumab (Ebglyss) | IL-13 | Q2 week SQ for mod-severe AD |
Boards PearlDupilumab (Dupixent) is the blockbuster biologic for atopic dermatitis. Mechanism: blocks shared IL-4Rฮฑ receptor subunit โ blocks BOTH IL-4 (Th2 differentiation) AND IL-13 (IgE production, itch signaling). Does NOT cause immunosuppression like TNF inhibitors.
JAK Inhibitors for Dermatology
Upadacitinib (Rinvoq), abrocitinib (Cibinqo) โ oral JAK inhibitors for atopic dermatitis. Ruxolitinib cream (Opzelura) โ topical JAK inhibitor for mild-mod AD. Baricitinib โ alopecia areata. Tofacitinib โ psoriasis and alopecia areata (off-label). FDA black box: thrombosis, MACE, malignancy, serious infections (oral JAKi).
Acne Vulgaris Treatment Ladder
| Severity | First-Line | Second-Line |
|---|---|---|
| Mild (comedonal) | Topical retinoid (adapalene) ยฑ BPO | Add topical antibiotic (clindamycin) |
| Mild-moderate (papulopustular) | Topical retinoid + BPO + topical clindamycin | Dapsone 5โ7.5% gel; azelaic acid |
| Moderate (papulopustular) | Oral doxycycline 50โ100mg daily + topical retinoid + BPO | Oral minocycline; Sarecycline (narrow spectrum) |
| Severe (nodular/cystic) | Oral isotretinoin (see above) | Oral spironolactone (females); combined OCP |
| Female hormonal acne | COC (norgestimate-EE); spironolactone 50โ100mg | Clascoterone (Winlevi) โ topical anti-androgen cream |
Key Agents
- Benzoyl peroxide (BPO): bactericidal against C. acnes; prevents antibiotic resistance; always combine with topical antibiotics
- Clindamycin topical: most common topical antibiotic; gel or lotion; ALWAYS with BPO to prevent resistance
- Doxycycline: preferred oral antibiotic; take with food (GI upset); photosensitivity; esophagitis if not washed down
- Azelaic acid 15โ20%: anti-inflammatory, anti-comedonal, hyperpigmentation; safe in pregnancy
Boards PearlDo NOT use topical antibiotics (clindamycin) alone without BPO โ resistance develops. Oral antibiotics should be used for โค3โ6 months then transition to topical regimen. Sarecycline (Seysara) โ narrow-spectrum tetracycline for acne; less GI side effects than doxy; better C. acnes selectivity.
Rosacea Pharmacotherapy
Subtypes & Treatments
| Subtype | Features | Treatment |
|---|---|---|
| Erythematotelangiectatic (ETR) | Flushing, erythema, telangiectasias | Brimonidine gel 0.33% (Mirvaso) or oxymetazoline cream 1% (Rhofade); laser/IPL for telangiectasias; avoid triggers |
| Papulopustular | Papules/pustules resembling acne (no comedones) | Metronidazole 0.75โ1% gel/cream (first-line); azelaic acid 15% gel; ivermectin 1% cream (Soolantra); topical BPO; oral doxy 40mg DR (Oracea) for moderate-severe |
| Phymatous | Rhinophyma (nose thickening) | Laser ablation; isotretinoin (medical); surgery |
| Ocular | Blepharitis, conjunctivitis, keratitis | Lid hygiene; oral doxycycline 40โ100mg; cyclosporine eye drops |
Trigger AvoidanceHot drinks, spicy food, alcohol (especially red wine), temperature extremes, UV exposure, emotional stress, exercise. Sunscreen (broad-spectrum SPF 30+) is essential daily.
Boards PearlBrimonidine (alpha-2 agonist) โ causes vasoconstriction; treats persistent erythema/flushing only (no papules). Rebound erythema may occur after cessation. Ivermectin cream (Soolantra) โ kills Demodex mites; anti-inflammatory; better long-term efficacy than metronidazole for papulopustular rosacea in some trials. Oracea (doxycycline 40mg modified-release) โ sub-antimicrobial dose; anti-inflammatory mechanism; lower resistance risk.
Dermatologic Antifungals
Topical Antifungals
| Drug | Class | Spectrum | Use |
|---|---|---|---|
| Clotrimazole (Lotrimin) | Azole | Dermatophytes, Candida | Tinea pedis/corporis/cruris, cutaneous candidiasis; OTC |
| Miconazole (Monistat) | Azole | Dermatophytes, Candida | Vulvovaginal candidiasis (OTC); tinea infections |
| Terbinafine (Lamisil) | Allylamine (inhibits squalene epoxidase) | Dermatophytes primarily | Tinea pedis (1 wk cream), nail involvement; cream OTC |
| Ciclopirox (Penlac) | Hydroxypyridinone | Broad spectrum including Candida | Onychomycosis (lacquer), tinea versicolor, seborrheic dermatitis |
| Ketoconazole 2% shampoo/cream | Azole | Dermatophytes, Candida, M. furfur | Seborrheic dermatitis, tinea versicolor; oral ketoconazole avoided (hepatotoxic) |
| Nystatin (Mycostatin) | Polyene | Candida only | Oral thrush, diaper dermatitis, vulvovaginal candidiasis; NOT effective for tinea |
Systemic Antifungals for Skin/Nails
| Drug | Indication | Duration/Notes |
|---|---|---|
| Terbinafine oral (Lamisil) | Onychomycosis (toenail/fingernail), tinea capitis | Toenail: 12 wks; fingernail: 6 wks. Check LFTs at baseline. Hepatotoxic (rare). Drug interactions via CYP2D6. |
| Itraconazole (Sporanox) | Onychomycosis, tinea capitis, tinea unguium | Pulse dosing: 200mg BID x1wk/month x2-3 months. Many drug interactions (CYP3A4); negative inotrope โ CI in HF |
| Fluconazole (Diflucan) | Vulvovaginal candidiasis, tinea versicolor, Candida infections | VVC: 150mg x1 dose. Tinea versicolor: 400mg x1 or 200mg weekly x2. CYP2C9/3A4 inhibitor; prolongs QT |
| Griseofulvin | Tinea capitis (children โ preferred) | 6โ8 weeks; take with fatty meal; teratogenic โ avoid in pregnancy; antifungal resistance emerging |
Boards PearlOnychomycosis diagnosis: KOH prep or fungal culture (PAS stain on nail biopsy) before starting systemic antifungals โ chronic nail changes have many mimics (psoriasis, trauma). Terbinafine oral = first-line for onychomycosis (best cure rates, 70โ80% toenail). Topical antifungals NOT effective for onychomycosis (poor nail penetration) except efinaconazole and tavaborole for mild cases.
Antivirals for Skin Conditions
Herpes Simplex & Varicella-Zoster
| Drug | Indication | Dose/Duration | Notes |
|---|---|---|---|
| Acyclovir (Zovirax) | HSV-1/2, VZV, primary episodes | HSV: 400mg TID x5-10d; VZV: 800mg 5x/day x7d | IV for immunocompromised, encephalitis, disseminated zoster; renal dose adjustment; well-tolerated |
| Valacyclovir (Valtrex) | HSV (oral/genital), VZV, herpes zoster | Zoster: 1g TID x7d; HSV suppression: 500mg-1g daily | Prodrug of acyclovir; better bioavailability; preferred over acyclovir for most outpatient indications |
| Famciclovir (Famvir) | Herpes zoster, genital HSV | Zoster: 500mg TID x7d; HSV recurrence: 1000mg BID x1d | Prodrug of penciclovir; equivalent to valacyclovir; used in immunocompromised |
Herpes Zoster TreatmentStart antivirals within 72 hours of rash onset (most benefit). Reduces duration, severity, and risk of postherpetic neuralgia (PHN). ALL immunocompromised patients and those with ophthalmic zoster require treatment regardless of timing. Ophthalmic zoster (V1 branch of CN V): refer to ophthalmology urgently.
Boards PearlHutchinson's sign: vesicle on tip of nose (nasociliary branch of V1) โ predict ocular involvement in herpes zoster. Treat ophthalmic zoster with IV acyclovir if immunocompromised or severe; oral valacyclovir for immunocompetent. Postherpetic neuralgia treatment: gabapentin, pregabalin, TCAs (amitriptyline), lidocaine patch, capsaicin 8% patch (Qutenza).
Molluscum Contagiosum & Warts
Molluscum: cantharidin (provider-applied vesicant), podophyllotoxin, imiquimod; most self-resolve in immunocompetent. Common warts: salicylic acid (OTC), cryotherapy with liquid nitrogen, cantharidin, laser; HPV warts โ see STI section (imiquimod, podofilox, TCA).
Miscellaneous Dermatologic Agents
Calcineurin Inhibitors (Non-Steroidal Anti-Inflammatory)
Tacrolimus ointment (Protopic 0.03%/0.1%) and pimecrolimus cream (Elidel 1%) โ T-cell calcineurin inhibitors โ block IL-2 production โ anti-inflammatory. Use for atopic dermatitis on face/skin folds (where steroids not ideal). Black box: rare theoretical lymphoma/skin cancer risk (use only if standard treatments fail). Second-line for atopic dermatitis.
PDE4 Inhibitors
Crisaborole (Eucrisa) 2% ointment โ topical PDE4 inhibitor โ โ cAMP โ anti-inflammatory. Mild-moderate atopic dermatitis โฅ2 years old. Burning/stinging at application site. Alternative to topical steroids. Roflumilast 0.3% cream (Zoryve) โ FDA approved for psoriasis (mild-moderate) without systemic risks of oral roflumilast.
Methotrexate for Psoriasis
Oral MTX: folate antagonist; suppress rapidly dividing keratinocytes and T-cell proliferation. Dose: 7.5โ25mg weekly. Monitor: CBC, LFTs, BMP, renal function. Side effects: hepatotoxicity (dose-cumulative โ liver biopsy if high cumulative dose), bone marrow suppression, teratogenicity. Supplement with folic acid 1mg daily (taken day AFTER MTX). CI: hepatic disease, active infection, immunodeficiency, renal impairment, pregnancy.
Boards PearlMTX + folic acid: give folic acid 1mg daily 6 days/week (NOT on MTX day) to reduce side effects (mucositis, GI upset, hepatotoxicity) without reducing efficacy. If leucovorin rescue needed (toxicity/overdose): leucovorin (folinic acid) binds DHFR receptors and reverses MTX toxicity.
Scabies Treatment
| Drug | Application | Notes |
|---|---|---|
| Permethrin 5% cream (Elimite) | Apply neck-to-toe, leave 8โ14h, rinse; repeat in 1 week | First-line; safe in pregnancy and infants >2mo; treat ALL household contacts simultaneously |
| Ivermectin oral | 200mcg/kg x1, repeat in 2 weeks | Alternative; preferred for crusted (Norwegian) scabies; NOT for children <15kg or pregnant women |
Lice Treatment
Permethrin 1% cream rinse (Nix) โ first-line; OTC; apply after shampoo 10 min then rinse; repeat in 9โ10 days. Malathion 0.5% lotion โ if permethrin-resistant. Ivermectin 0.5% lotion (Sklice) โ single application; Rx. Oral ivermectin โ for resistant cases.