Atopic Dermatitis Study Notes

Course Overview and Derm Study Strategies

• Study Tips for Dermatology:

  • Know the basic presentation of each condition, including key patient characteristics, physical location on the body, and signs or symptoms.

  • Memorize brand and generic names and their specific indications.

  • Utilize the "Derm Exam Resource" worksheet for Brand/Generic names.

  • Prioritize studying treatment algorithms, specifically identifying first-line, second-line, and alternative therapeutic options.

  • Do not neglect non-pharmacologic treatment options.

  • Exam focus: Choosing the most appropriate therapy for a given scenario.

Topical Corticosteroid (TCS) Potency Classification

• Low Potency (Class 6 & 7):

  • Mnemonic: "HAFD the strength"

  • Hydrocortisone, Alclometasone, Fluocinolone, Desonide

  • Hydrocortisone ($0.5\%$ & $1.0\%$): OTC Brand names: $Cortaid$ , $Cortizone$,$Lanacort$. Route: Topical. Dosing: Apply BID (Twice daily).

  • Hydrocortisone ($2.5\%$): Brand name: $Hytone$ . Status: Rx.

  • Alclometasone: Brand name: $Aclovate$. Status: Rx.

  • Fluocinolone acetonide: Brand name: $Synalar$. Status: Rx.

  • Desonide: Brand name: $DesOwen$. Status: Rx.

• Medium Potency (Class 3 - 5):

  • Mnemonic: "For Her Majesty VAL, a MEDIUM rare T-Bone steak."

  • Fluticasone propionate: Brand name: $Cutivate$. Route: Topical. Dosing: Apply BID. Status: Rx.

  • Hydrocortisone valerate: Brand name: $Westcort$. Status: Rx.

  • Mometasone furoate: Brand name: $Elocon$. Status: Rx.

  • Betamethasone valerate: Brand name: $Valisone$. Status: Rx. (Note: Potency may vary depending on concentration/strength).

  • Triamcinolone acetonide: Brand name: $Kenalog$. Status: Rx. (Note: Potency may vary depending on concentration/strength).

• High Potency (Class 2):

  • Mnemonic: "The -CINONIDEs and DI- rhyme with HIGH."

  • Amcinonide: Brand name: $Cyclocort$. Route: Topical. Dosing: Apply BID. Status: Rx.

  • Fluocinonide: Brand name: $Lidex$. Status: Rx.

  • Halocinonide: Brand name: $Halog$. Status: Rx.

  • Diflorasone diacetate: Brand name: $Psorcon$. Status: Rx.

• Very High Potency / Super-potent (Class 1):

  • Mnemonic: "My BETA fish, NATE is VERY HIGH-ly aggressive."

  • Betamethasone dipropionate: Brand name: $Diprolene$. Route: Topical. Dosing: Apply BID. Status: Rx.

  • Halobetasol propionate: Brand names: $Temovate$, $Ultravate$. Status: Rx.

Non-Steroidal Therapeutic Agents

• Topical Calcineurin Inhibitors (TCI):

  • Tacrolimus ointment: Brand name: $Protopic$. Route: Topical. Dosing: Apply BID for flares; BIW (Twice weekly) for maintenance. Status: Rx.

  • Pimecrolimus cream: Brand name: $Elidel$. Route: Topical. Dosing: Apply BID. Status: Rx.

• Janus Kinase (JAK) Inhibitors:

  • Ruxolitinib cream: Brand name: $Opzelura$. Route: Topical. Status: Rx.

  • Delgocitinib cream: Brand name: $Anzupgo$. Route: Topical. Indicated for moderate to severe AD on hands/wrists only.

  • Abrocitinib: Brand name: $Cibinqo$. Route: Oral. Status: Rx.

  • Upadacitinib ER: Brand name: $Rinvoq$. Route: Oral. Status: Rx.

• Phosphodiesterase-4 (PDE-4) Inhibitors:

  • Crisaborole ointment ($2\%$): Brand name: $Eucrisa$. Route: Topical. Dosing: Apply BID. Status: Rx.

  • Roflumilast cream ($0.15\%$ & $0.05\%$): Brand name: $Zoryve$. Route: Topical. Dosing: Apply once daily. Status: Rx.

  • Difamilast ointment ($1\%$): Brand name: $Adquey$. Route: Topical. Dosing: Apply BID.

• Biologics / Monoclonal Antibodies:

  • Dupilumab: Brand name: $Dupixent$. MOA: Inhibits $IL-4$ and $IL-13$. Route: SC (Subcutaneous). Dosing: Every $2$ weeks.

  • Tralokinumab: Brand name: $Adbry$. MOA: Inhibits $IL-13$. Route: SC. Dosing: Every $2$ weeks.

  • Lebrikizumab: Brand name: $Ebglyss$. MOA: Inhibits $IL-13$. Route: SC. Dosing: Every $2$ weeks.

  • Nemolizumab: Brand name: $Nemluvio$. MOA: Inhibits $IL-31$. Route: SC. Dosing: Every $4$ weeks.

• Topical Antibiotics:

  • Mupirocin ointment: Brand name: $Bactroban$. Route: Topical. Dosing: Apply BID-TID.

OTC Baths, Cleansers, and Moisturizers

• Cleansers:

  • Mild, non-soap cleanser ($Cetaphil$): Used in place of soap.

  • Glycerin Soap ($Neutrogena$): Contains TEA-Stearate and triethanolamine.

• Colloidal Oatmeal:

  • Colloidal oatmeal ($\pm$ mineral oil): Brand name: $Aveeno Oatmeal Bath$.

  • Administration: Use in warm bath; soak for $15-20$ minutes once or twice daily. Pat skin dry to leave a film of oatmeal.

• Moisturizers and Emollients:

  • Petrolatum: Brand name: $Aquaphor$. Dosing: Apply $3$ to $4$ times daily (more if washing frequently).

  • Lanolin: Used as a moisturizer/emollient.

  • Urea: Mild keratolytic and humectant. Dosing: Apply $3$ to $4$ times daily.

  • Alpha hydroxy acid: Brand names: $AmLactin$ , $Lac-Hydrin$. Generic: Ammonium lactate/Lactic acid.

Antihistamines

• Topical Antihistamines:

  • Brand name: $Benadryl$ Cream/Gel. Generic: Diphenhydramine. Dosing: Apply BID. Maximum duration: $7$ days due to sensitizing potential.

• Oral Antihistamines (First Generation):

  • Diphenhydramine ($Benadryl$): OTC. Dosage: $25-50\,mg$ PO QHS (at bedtime).

  • Hydroxyzine pamoate ($Vistaril$): Rx. Dosage: PO TID-QID PRN (typically QHS due to sedation).

  • Hydroxyzine hydrochloride ($Atarax$): Rx.

Clinical Definitions of Dermatitis

• Dermatitis: A nonspecific term covering various disorders characterized by erythema (redness) and inflammation.

• Xerosis: The medical term for dry skin.

• Eczema: A group of inflammatory skin disorders, often of unknown cause.

• Atopic Dermatitis (AD): A form of eczema ("atopic eczema") that is chronic, characterized by a lifetime of flares and remissions.

Presentation and Differentiating Characteristics

• Atopic Dermatitis (AD):

  • Hallmark symptom: Pruritus (itching). "The itch that rashes."

  • Onset: Often in early childhood. $50\%$ diagnosed in 1st year of life (typically $2-3$ months); $85\%$ by age $5$.

  • Atopic Triad: Co-occurrence of Asthma, Allergic Rhinitis, and Atopic Dermatitis.

  • Location by Age:

    • Adults: Skin creases (flexure surfaces like antecubital and popliteal fossae), neck, and hands.

    • Children/Infants: Face (cheeks, forehead, neck) and extremities.

  • Forms of AD:

    • Acute: Intense pruritus, red papules/vesicles, clear exudate, crusts.

    • Subacute: Red, excoriated papules; scratching leads to scaly plaques.

    • Chronic: Lichenified (thickened) plaques.

• Xerosis:

  • Common in older patients. Presents as rough skin, scales, and fissures. Pruritus and loss of flexibility occur. Usually found on limbs.

• Contact Dermatitis:

  • Can affect anyone. Presents as papules or vesicles over inflamed skin. Irritant contact dermatitis often causes scaling and fissures. Itching/burning occurs specifically at the site of contact.

• Dermatological Terminology:

  • Papule: A solid elevation up to $0.5\,cm$.

  • Excoriation: Skin abrasions typically from scratching.

  • Lichenification: Thickening of the skin with exaggerated markings.

  • Vesicle: Small, fluid-filled blister.

Severity Assessment and Digital Tools

• SCORAD (Severity Scoring of Atopic Dermatitis) Index:

  • Calculation: $\text{SCORAD} = \frac{A}{5} + \frac{7B}{2} + C$

  • A (Extent): Percentage of area involved.

    • Head involvement is $4.5\%$ for adults ($8.5\%$ for children under $2$).

    • Trunk is $18\%$ (front) and $18\%$ (back).

    • Arms are $4.5\%$ each.

    • Legs are $9\%$ each.

  • B (Intensity): Rated $0-3$ (Absence, Mild, Moderate, Severe) for Erythema, Edema/papulation, Oozing/Crusting, Excoriations, Lichenification, and Dryness (evaluated on uninvolved skin).

  • C (Subjective Symptoms): Visual analog scale ($0-10$) for Pruritus and Sleep Loss (average of last $3$ days/nights).

Triggers and Exclusions for Self-Care

• Common Triggers:

  • Food: Eggs, milk, peanuts, soy, wheat, nuts, strawberries.

  • Aeroallergens: Dust mites, cat dander, mold, pollen.

  • Airborne Irritants: Tobacco smoke, air pollution.

  • Others: Cosmetics/fragrances, psychological stress, extreme temperatures, excessive hand washing, irritating clothing (wool/synthetics), dyes/preservatives.

Treatment Algorithms and Non-Pharmacologic Care

• General Algorithm:

  • Baseline: Basic therapy involving moisturizers and non-pharmacologic interventions.

  • Mild-Moderate: Topical steroids, TCIs, PDE-4 inhibitors, or topical JAK inhibitors.

  • Severe: Systemic immunosuppression.

• Bathing Recommendations:

  • Brief sessions ($3-5$ minutes).

    • Frequency: $2-3$ times per week (sponge baths on other days).

    • Water temperature: Lukewarm/tepid (not more than $3^{\circ}$ above body temperature).

    • Cleansers: Non-soap ($Cetaphil$, $Neutrogena$ glycerin soap).

    • Moisturizing: Apply scent-free moisturizer liberally immediately after bathing while skin is still damp.

Pharmacotherapy: Detailed Agent Profiles

• Emollients and Moisturizers:

  • Types: Lotions (thinnest), Creams, Ointments (thickest/most lipophilic).

  • MOA: Fill space between desquamating skin scales.

  • Ointments: Occlusive, provide better hydration and increased drug absorption. Avoid on weeping/infected skin.

  • Side Effects: Often caused by fragrances or ingredients like lanolin.

• Urea:

  • MOA: Keratolytic; increases water uptake in stratum corneum; binds skin proteins to increase elasticity.

  • Strengths: $10\%$ for simple dry skin; $20-30\%$ for resistant scales.

  • Side Effects: Stinging or burning on broken skin.

• TCS Adverse Drug Reactions (ADRs):

  • Cutaneous: Atrophy (skin thinning), telangiectases (visible small blood vessels), striae (stretch marks), acne, hypopigmentation, alopecia, or hypertrichosis.

  • Systemic Risk Factors: Long duration, high potency, use on large BSA, application to thin skin (face, genitals, intertriginous areas), or application to broken skin.

  • Specific Systemic ADRs: Adrenal suppression, Cushing’s syndrome, decreased growth in children, osteoporosis, glaucoma, increased infection risk, hypertension, centripetal fat distribution, and hypokalemia.

• Topical Calcineurin Inhibitors (TCIs):

  • Advantages: No skin atrophy; can be used on sensitive areas for prolonged (episodic) periods.

  • Side Effects: Transient stinging/burning.

  • Black Box Warning (BBW): Rare malignancies (skin cancer, lymphoma). Avoid in immunocompromised patients (HIV, chemotherapy). Sunscreen must be used.

• Topical Janus Kinase (JAK) Inhibitors:

  • BBW: Serious infections, mortality, malignancy (lymphoma, lung cancer), MACE (Major Adverse Cardiovascular Events like heart attack/stroke), and thrombosis (DVT, PE, arterial thrombosis).

Dosing and the Fingertip Method

• The Fingertip Unit (FTU):

  • $1 \text{ fingertip (from tip of finger to first joint)} = 0.5\,g$.

  • $1 \text{ fingertip}$ covers the area of $2 \text{ adult hands}$.

  • $1 \text{ hand-print} \approx 1\% \text{ BSA}$.

  • Therefore: $0.5\,g = 2\% \text{ BSA}$; $1\,g = 4\% \text{ BSA}$.

• Sample Calculation (Slide 79):

  • Scenario: Area is $2$ hand-prints behind each knee ($4$ hand-prints total).

  • $4 \text{ hand-prints} = 2 \text{ FTUs} = 1.0\,g$ per application.

  • Dosing: BID ($2.0\,g$ per day).

  • Supply: $60\,g$ tube.

  • Duration: $\frac{60\,g}{2.0\,g/day} = 30 \text{ days}$.

• Sample Calculation (Slide 81):

  • Scenario: Area is $1$ hand-print behind each knee ($2$ hand-prints total).

  • $2 \text{ hand-prints} = 1 \text{ FTU} = 0.5\,g$ per application.

  • Dosing: BID ($1.0\,g$ per day).

  • Supply: $15\,g$ tube.

  • Duration: $\frac{15\,g}{1.0\,g/day} = 15 \text{ days}$.

Questions & Discussion

• Question: Which of the following is a LOW potency topical corticosteroid?

  • Answer: Hydrocortisone ($D$).

• Question: Which of the following is a VERY HIGH potency topical corticosteroid?

  • Answer: Clobetasol ($B$).

• Question: Which of the following is a JAK inhibitor?

  • Answer: Abrocitinib ($A$).

• Question: What is the hallmark symptom of atopic dermatitis?

  • Answer: Pruritus ($C$).

• Question: Which are included in the atopic triad?

  • Answer: Asthma, AT, and Allergic Rhinitis (I, II, and III).

• Question: Which antihistamine is most likely to work for pruritus?

  • Answer: Diphenhydramine ($A$) - primarily due to its sedative properties rather than H1 blockade efficacy in AD skin.

• Question: Which is a prescription antihistamine?

  • Answer: Atarax ($A$).

• Question: Which does NOT have a BBW?

  • Answer: Desonide ($B$). (Abrocitinib, Pimecrolimus, Tacrolimus, and Upadacitinib all have BBWs).