💊Pharmacology for Nurses Unit 40 – Dermatologic Disorder Drugs

Overview of Dermatologic Disorders

• Dermatologic disorders affect the skin, hair, and nails, ranging from mild to severe and acute to chronic
• Common types include infectious (bacterial, viral, fungal), inflammatory (eczema, psoriasis), and neoplastic (benign and malignant tumors) conditions
• Skin disorders can cause significant physical discomfort (itching, pain) and psychological distress (self-consciousness, anxiety) for patients
• Prevalence varies by age, with certain conditions more common in pediatric (diaper dermatitis) or geriatric (pressure ulcers) populations
• Environmental factors like sun exposure (UV radiation), occupational hazards (chemical irritants), and lifestyle habits (smoking) can contribute to dermatologic issues
• Diagnosis involves visual examination, skin scrapings or biopsies, and laboratory tests (culture and sensitivity) to identify causative agents or underlying pathologies
• Treatment goals include relieving symptoms, preventing complications (infection, scarring), and improving quality of life through pharmacologic and non-pharmacologic interventions

Key Skin Anatomy and Physiology

• The skin is the largest organ of the body, serving as a protective barrier, regulating temperature, and facilitating sensory perception
• Composed of three main layers: epidermis (outermost), dermis (middle), and hypodermis (deepest)
  • Epidermis consists of keratinocytes that undergo keratinization to form a waterproof barrier
  • Dermis contains collagen and elastin fibers for strength and elasticity, as well as blood vessels, nerves, and appendages (hair follicles, sweat glands)
• Skin pH is slightly acidic (4.5-6.5), helping to prevent microbial growth and maintain moisture balance
• Melanocytes in the basal layer of the epidermis produce melanin, the pigment responsible for skin color and UV protection
• Langerhans cells in the epidermis are part of the immune system, detecting and presenting antigens to activate T-lymphocytes
• Skin turnover (cell renewal) occurs every 28-30 days, with dead cells shed from the surface (desquamation) and replaced by new cells from the basal layer
• Sebaceous glands secrete sebum (oils) to lubricate and waterproof the skin, while eccrine sweat glands help regulate body temperature through evaporation

Common Dermatologic Conditions

• Acne vulgaris is a chronic inflammatory disorder of the pilosebaceous unit (hair follicles and sebaceous glands), characterized by comedones (blackheads, whiteheads), papules, pustules, and nodules
• Atopic dermatitis (eczema) is a chronic, relapsing inflammatory condition causing pruritic, erythematous, and scaly patches on flexural surfaces (antecubital and popliteal fossae)
• Psoriasis is an autoimmune disorder resulting in the rapid proliferation of keratinocytes, forming thick, silvery scales on extensor surfaces (elbows, knees) and the scalp
• Rosacea is a chronic inflammatory condition affecting the face, presenting with erythema, telangiectasia, papules, and pustules
• Seborrheic dermatitis is a chronic, relapsing inflammatory dermatosis characterized by greasy, yellow scales on the scalp (dandruff), face, and chest
• Fungal infections like tinea corporis (ringworm), tinea pedis (athlete's foot), and onychomycosis (nail fungus) are caused by dermatophytes invading the stratum corneum
• Viral infections such as herpes simplex (cold sores), varicella-zoster (shingles), and human papillomavirus (warts) can cause localized skin lesions
• Bacterial infections like impetigo (Staphylococcus aureus, Streptococcus pyogenes) and cellulitis (deeper soft tissue infection) require prompt treatment to prevent spread

Pharmacological Approaches

• Topical medications are the mainstay of treatment for most dermatologic conditions, delivering active ingredients directly to the affected area while minimizing systemic absorption
  • Formulations include creams, ointments, gels, lotions, and solutions, each with specific properties (occlusion, hydration) suited for different skin types and lesions
• Systemic medications (oral or injectable) may be necessary for severe, widespread, or refractory cases not responding to topical therapy alone
• Combination therapy using multiple agents with different mechanisms of action can provide synergistic effects and improve treatment outcomes
• Antimicrobial agents (antibiotics, antifungals, antivirals) are used to treat infectious skin conditions, targeting specific causative organisms
• Anti-inflammatory agents (corticosteroids, calcineurin inhibitors) reduce inflammation, pruritus, and erythema in conditions like atopic dermatitis and psoriasis
• Retinoids (vitamin A derivatives) regulate cell proliferation and differentiation, making them useful for acne, psoriasis, and photoaging
• Immunomodulators (biologics) target specific cytokines or immune pathways involved in the pathogenesis of inflammatory skin disorders like psoriasis and atopic dermatitis
• Keratolytic agents (salicylic acid, urea) soften and exfoliate the stratum corneum, facilitating the penetration of other topical medications and removing scales

Major Drug Classes and Mechanisms

• Topical corticosteroids (hydrocortisone, betamethasone) are the most widely used anti-inflammatory agents, suppressing the production of pro-inflammatory cytokines and reducing capillary permeability
  • Potency ranges from class VII (lowest) to class I (highest), with selection based on the severity and location of the lesion
• Topical calcineurin inhibitors (tacrolimus, pimecrolimus) inhibit T-cell activation and cytokine production, providing a steroid-sparing alternative for atopic dermatitis
• Topical retinoids (tretinoin, adapalene) normalize keratinocyte differentiation, reduce comedogenesis, and promote collagen synthesis, making them effective for acne and photoaging
• Topical antibiotics (clindamycin, erythromycin) inhibit bacterial protein synthesis, reducing the proliferation of P. acnes in acne and treating superficial skin infections
• Topical antifungals (ketoconazole, terbinafine) disrupt fungal cell membranes or inhibit ergosterol synthesis, treating dermatophyte infections like tinea and candidiasis
• Oral antibiotics (doxycycline, minocycline) have anti-inflammatory properties in addition to their antimicrobial effects, making them useful for moderate to severe acne
• Oral retinoids (isotretinoin) are reserved for severe, nodular acne unresponsive to other therapies, inducing apoptosis in sebaceous glands and reducing sebum production
• Biologics (adalimumab, ustekinumab) target specific cytokines (TNF-α, IL-12/23) involved in the pathogenesis of psoriasis and other inflammatory skin disorders, interrupting the inflammatory cascade

Administration and Dosing

• Topical medications should be applied in a thin, even layer to the affected area, avoiding excessive occlusion which can increase systemic absorption
  • Frequency of application varies from once daily to four times daily, depending on the specific medication and the condition being treated
• Patients should be instructed on the proper application technique (fingertip unit) and the importance of consistent use for optimal results
• Oral medications should be taken with food or milk to minimize gastrointestinal irritation, and at the same time each day to maintain steady-state levels
• Dosing for oral medications is based on weight, age, and renal/hepatic function, with adjustments made as necessary based on clinical response and tolerability
• Isotretinoin requires enrollment in the iPLEDGE program, with monthly pregnancy tests and dispensing limits due to its teratogenic potential
• Biologics are administered by subcutaneous injection or intravenous infusion, with dosing intervals ranging from every other week to every 12 weeks
• Proper storage of medications is essential, with most topical products kept at room temperature and protected from light and moisture
• Patients should be advised not to share their medications with others, as this can lead to misuse and potential adverse effects

Side Effects and Adverse Reactions

• Topical corticosteroids can cause local side effects like skin atrophy, striae, telangiectasia, and hypopigmentation with prolonged use, as well as systemic effects (HPA axis suppression) if used over large areas or under occlusion
• Topical retinoids commonly cause dryness, erythema, and peeling (retinoid dermatitis) during the first few weeks of treatment, which can be managed with moisturizers and gradual titration of the medication
• Oral antibiotics can cause gastrointestinal upset, photosensitivity, and vaginal candidiasis, requiring the use of probiotics and sun protection
• Isotretinoin is associated with severe birth defects, necessitating the use of two forms of contraception in female patients of childbearing potential
  • Other side effects include dry skin and mucous membranes, elevated liver enzymes and lipids, and pseudotumor cerebri
• Biologics can increase the risk of infections (tuberculosis reactivation) and malignancies (lymphoma), requiring screening tests and close monitoring
• Patients should be advised to report any unusual symptoms or worsening of their condition to their healthcare provider promptly
• Allergic reactions (urticaria, angioedema) can occur with any medication, and patients should be instructed on the signs and symptoms to watch for

Nursing Considerations and Patient Education

• Nurses play a critical role in assessing the patient's skin condition, monitoring for treatment response and adverse effects, and providing patient education
• A thorough skin assessment should be performed at each visit, documenting the type, location, and severity of lesions, as well as any signs of infection or other complications
• Patients should be educated on the proper use and application of their medications, including the importance of consistent use and not exceeding the prescribed amount
• Nurses should reinforce the need for sun protection (SPF 30+) when using topical retinoids or oral antibiotics, as these medications can increase photosensitivity
• Patients using topical corticosteroids should be instructed to use the lowest potency and shortest duration necessary to control their symptoms, and to avoid applying them to the face, groin, or axillae unless specifically directed
• Nurses should assess the patient's understanding of their condition and treatment plan, providing additional education and resources as needed
• Patients should be encouraged to keep a symptom diary and to bring it to each appointment, as this can help track progress and identify potential triggers or aggravating factors
• Nurses should emphasize the importance of maintaining a healthy lifestyle (balanced diet, regular exercise, stress management) in addition to pharmacologic treatment for optimal management of dermatologic conditions
• Patients should be advised to avoid harsh soaps, detergents, and other potential irritants that can exacerbate their skin condition, and to use mild, fragrance-free products instead
• Nurses should provide emotional support and reassurance to patients, as dermatologic conditions can have a significant impact on self-esteem and quality of life