Study Notes on Atopic Dermatitis & Drug Induced Skin Disorders

Dermatology: Atopic Dermatitis & Drug Induced Skin Disorders

Objectives of the Atopic Dermatitis Section

  1. Understand SCORAD scoring and its significance regarding treatment choice.

  2. Determine non-pharmacotherapy counseling recommendations for atopic dermatitis.

  3. Understand referral moments for patients to a primary care provider.

  4. Identify optimal pharmacotherapy options for atopic dermatitis.

Background

  • Epidemiology

  • Etiology

  • Pathophysiology

  • Diagnosis

Types of Eczema (Dermatitis)

  • Allergic Contact Eczema (Dermatitis):

    • Reaction with redness, itching, weeping on contact with known allergens (e.g., poison ivy).

  • Atopic Dermatitis:

    • Chronic, itchy inflammatory skin disease.

  • Contact Eczema (Dermatitis):

    • Localized reaction due to exposure to allergen/irritant presenting with itch and redness.

  • Dyshidrotic Eczema:

    • Often seen on palms and soles; presents as deep, itchy blisters.

  • Neurodermatitis:

    • Scaly skin patches from localized itch.

  • Nummular Eczema:

    • Coin-shaped itchy patches.

  • Seborrheic Eczema:

    • Yellowish, oily scaliness primarily affecting the scalp and face.

  • Stasis Dermatitis:

    • Occurs in lower legs due to circulatory factors.

Atopic Dermatitis (AD) aka Eczema

  • Characteristics:

    • Chronic pruritic inflammatory skin disease.

    • Clinical Presentation:

    • Hallmark symptom: Pruritis (itching)

    • Other symptoms: Xerosis (dry skin) leading to waxing and waning of symptoms.

    • Common Locations:

    • Cheeks, forehead, scalp, chin, behind ears, neck, trunk.

    • Can extend to the rest of the body.

    • Visual Indicators:

      • Erythematous (red appearance), papular eruption, scaling, oozing skin.

Atopic Dermatitis in Adults

  • Characteristics:

    • Lesions are more diffuse than in children.

    • Increased erythema and involvement of the face with dry, scaly skin.

    • Lichenification:

    • Rough thickened skin due to chronic scratching.

    • Hypopigmented macular lesions:

    • Result from healed lesions affecting the cheeks.

Epidemiology and Etiology of Atopic Dermatitis

  • Epidemiology Statistics:

    • Affects 15-30% of children, 2-10% of adults.

    • 65% develop symptoms before 1st year of life.

    • Typical onset occurs between 3-6 months.

  • Risk Factors:

    • Environmental factors, genetics, immunology, skin barrier dysfunction.

Pathophysiology of Atopic Dermatitis

  • Chronic inflammatory skin disease with an unknown initial trigger for inflammation.

  • Irritation-induced scratching:

    • Releases pro-inflammatory cytokines from keratinocytes.

    • Creates a cycle where itch leads to damage which perpetuates the inflammation.

  • Itch-Scratch Cycle:

    • Damages the skin further, leading to enhanced inflammation.

Diagnosis and Complications

  • Diagnosis:

    • Based on symptoms and clinical presentation using SCORAD.

  • Complications Include:

    • Secondary bacterial or fungal infections, often requiring systemic antibiotics.

    • Most common infection: Staphylococcus aureus.

    • Ocular issues: conjunctivitis, eyelid dermatitis.

    • Potential for scarring, sleep disturbances, behavioral changes, and growth disruptions.

    • Skin pigmentation changes.

Clinical Features of Atopic Dermatitis

  • Essential Features Needed for Diagnosis:

    • Pruritus

    • Eczema presence

    • Distribution on face, neck, and external areas for infants/children.

    • Chronic/relapsing history:

    • Early age of onset, personal/family history of atopy, IgE reactivity, xerosis.

Treatment Goals

  • Objective of Treatment:

    • Create a tailored regimen that alleviates symptoms and restores skin appearance similar to normal.

    • Identify and mitigate triggers.

    • Relieve symptoms and prevent exacerbations while reducing medication adverse effects.

    • Enhance quality of life.

Non-Pharmacologic Counseling Points for AD

  • Trigger Identification and Reduction:

    • Focus on irritants/allergens, temperature/humidity, and emotional stress.

  • Skin Hydration Strategies:

    • Use unscented moisturizers liberally throughout the day.

  • Bathing Practices:

    • Lukewarm baths lasting 5-10 mins, followed by the application of moisturizers (soak & smear concept).

    • Prefer non-soap cleansers low in pH and allergens.

  • Wet-Wrap Therapy:

  • Fingernail Care:

    • Keep children's fingernails short to prevent scratching.

Nonpharmacologic Therapy Overview

  • General Practice:

    • Moisturizers should be applied frequently to restore skin integrity and percutaneous water loss management.

  • Types of Products:

    • Occlusives: Add an oily layer (ex: petrolatum).

    • Humectants: Increase moisture holding.

    • Emollients: Smoother skin by filling in spaces.

  • Recommended Products:

    • Aveeno Baby Soothing Relief Moisture Cream, CeraVe lotion, Cetaphil, Neutrogena products, Vanicream.

Pharmacotherapy Treatment Overview

  • 1st Line: Topical Corticosteroids

  • System for unresponsive cases:

    • 2nd Line includes Immunomodulators, Coal Tar, Phosphodiesterase-4 inhibitors.

  • Phototherapy plus calcineurin inhibitors may be necessary in severe cases.

  • Long-term management:

    • Frequent monitoring and adapt therapy as needed.

Topical Corticosteroids

  • Mechanism of Action:

    • Reduce inflammation, itch, and lesions.

  • Recommended Application Regimen:

    • Generally twice daily until lesions heal (approx. two weeks), then taper to once or twice weekly.

  • Adverse Effects:

    • Skin atrophy, striae distendae, potential HPA axis suppression, pregnancy concerns.

Topical Calcineurin Inhibitors

  • Mechanism: Block T cell activation.

  • Advantages: Long-term use on sensitive areas without steroid complications.

  • Common Products: Tacrolimus Ointment, Primecolimus Cream.

Drug Induced Skin Disorders Objectives

  1. Understand types of drug reactions.

  2. Identify common signs and symptoms of drug-induced skin disorders.

  3. Know common causative drug classes.

  4. Determine the common management strategy for drug-induced reactions.

  5. Know dosing and counseling for epinephrine.

Background on Drug Induced Skin Disorders

  • Epidemiology:

    • 15-20% of ADRs exhibit skin manifestations.

    • Approximately 636,000 annual healthcare visits.

Definitions of Drug Reactions

  • Irritant vs. Allergic:

    • Irritant reactions are localized without an immune response; allergic reactions necessitate it and may affect systemic regions.

  • Types of Adverse Drug Reactions (ADRs):

    • Adverse drug reactions, interactions, intolerance, and hypersensitivity/allergic responses.

Common Drug Reactions: Urticaria and Angioedema

  • Urticaria Characteristics:

    • Hives caused by IgE reactions; presents with extremely pruritic wheals.

  • Angioedema Symptoms:

    • Swelling beneath the skin, potentially affecting breathing.

Management of Urticaria and Angioedema

  • Management Strategies:

    • Discontinue offending drugs, use antihistamines, and for anaphylactic reactions administer epinephrine, steroids, and fluids.

SJS/TEN & Management

  • Signs of SJS/TEN:

    • Severe blistering with systemic symptoms; clinical management is critical with potential for life-threatening outcomes.

Overall Management of Drug-Induced Skin Reactions

  • Universal Management Principles:

    • Immediate discontinuation of the offending drug, supportive care, and thorough documentation.