Dermatology Lecture Review

Objectives for Dermatology Lecture

• Understand general pharmacotherapy when dealing with skin disorders

• Be able to describe pathophysiology, epidemiology, diagnosis, and treatment of skin disorders as cited in this lecture/reading materials.

Dermatology in Primary Care

• Speaker: Christina Snider, DNP, MSN, FNP-BC, PMHNP-BC

• Title: Associate Professor of Nursing

• Institution: University of Michigan-Flint SON

General Definitions Related to Skin Primary Lesions

• Lesion Size:

  • <1 cm:

  • Macule: flat discoloration

  • Papule: solid elevation

  • Vesicle: fluid-filled

  • Pustule: vesicle-like lesion with purulent content

• Lesion Size:

  • >1 cm:

  • Bulla: fluid-filled

  • Erosion: loss of epidermis

  • Ulcer: loss of epidermis and dermis

  • Patch: flat, non-palpable area of skin discoloration, larger than macule

  • Plaque: raised lesion, same or different color from surrounding skin, coalescence of papules

• Lesion Size:

  • Any size:

  • Wheal: circumscribed area of skin edema

  • Purpura: flat red-purple discoloration caused by RBCs lodged in the skin

  • Cyst: raised encapsulated fluid-filled lesion

Key Concepts – Secondary Lesions

• Important terms to know:

  • Excoriation: superficial loss of skin

  • Crust: dried secretion on the skin

  • Lichenification: thickening of skin due to chronic irritation

  • Scales: flaking off of skin

  • Erosion: loss of epidermis

  • Ulcer: deep loss of skin

  • Fissure: linear crack in the skin

Key Concepts – Distribution of Lesions

• Types:

  • Annular: ring-shaped

  • Scattered: randomly distributed

  • Confluent or Coalescent: merging lesions

  • Clustered: grouped together

  • Linear: in a line

  • Reticular: net-like pattern

  • Dermatomal: following a nerve root

General Pharmacotherapy with Skin Disorders

• Topical Corticosteroids: Types and Potencies:

  • Low potency:

  • Hydrocortisone: 0.5-2.5%

  • Mid potency:

  • Triamcinolone: 0.1%

  • High potency:

  • Fluocinonide: 0.05%

  • Super potency:

  • Clobetasol (propionate): 0.05%

• Usage Recommendations:

  • Use low potency for the face (thinnest skin) and thin skin areas.

Topical Steroid Potency

• Potency Categories (MPR, Fall 2017 ed.):

  • Low Potency:

  • Hydrocortisone (0.5-2.5%)

  • Fluocinolone Acetonide 0.01%, 0.2%

  • High Potency:

  • Fluocinonide 0.05%, Triamcinolone Acetonide 0.025%

  • Super High Potency:

  • Betamethasone Dipropionate Augmented 0.05%, Clobetasol Propionate 0.05%

• Coverage Guidelines:

  • One gram of corticosteroid covers a 10x10 cm area.

  • Various coverage areas require different amounts of corticosteroids:

  • 2 grams covers hands, head, face, or anogenitals.

  • 3 grams for anterior or posterior trunk or an arm.

  • 4 grams for a single lower extremity.

  • 30-60 grams cover entire skin surface.

Emollients/Ointments

• Ointment base: Oil in H2O

• Common forms: Eucerin, Nivea, Petroleum jelly

• Can irritate skin if alpha hydroxy acids are added.

• Ointments allow for maximum absorption; creams are next best; gels/lotions have the least absorption.

Topical Antifungals

• Polyenes:

  • Example: Nystatin (for Candida)

• Imidazoles:

  • Examples: Clotrimazole, Sulconazole, Ketoconazole (for Candida and dermatophytes)

• Allylamines:

  • Example: Lamisil (for dermatophytes)

Creams

• Generally applied 1-2 times daily until resolution unless specified otherwise.

Compresses/Baths

• Used to dry/debride areas of acute dermatitis.

• Examples of solutions:

  • Burow’s Aluminum Acetate 1:20

  • Domebro Aluminum Sulfate

  • Calcium Acetate

  • Aveeno colloidal oatmeal

Rate of Absorption

• Absorption rates vary:

  • Face: greatest rate of absorption

  • Axilla and genitals also have high absorption rates (especially diaper area in infants).

Office Tests

• Essential tests for skin conditions:

  • KOH: for fungal infections (dermatophyte)

  • Tzanck: for herpes infections

  • Mineral oil prep: for scabies

  • Biopsy: can be punch or excisional

  • Patch tests: for contact dermatitis

• In primary care, diagnosis is often made by appearance, and referral is common if no improvement after 1-2 rounds of treatment.

Superficial Infections

• Most common infecting organisms:

  • Streptococcus pyogenes and Staphylococcus aureus

• Consider MRSA in patients with comorbid conditions that may lead to serious infections.

Impetigo

• Definition: Acute, contagious skin infection.

• Causes: Primarily Staphylococcus aureus or Streptococcus pyogenes.

• Etiology: Often follows superficial trauma or occurs secondary to other conditions (e.g., scabies, herpes simplex).

• Symptoms: Begins with pruritic, superficial eruption of small (1-2 mm) vesicles that evolve to pustules, then crusted lesions with a golden honey appearance. May present with regional lymphadenopathy.

• Course: Typically self-limiting; persistent cases can lead to pigmentation changes and scarring.

Impetigo Treatment

• Mild cases: Mupirocin (Bactroban) for few lesions present.

• Severe cases: Antibiotics such as Dicloxacillin, Cephalexin, or Cefadroxil.

• Other management includes daily soaking of lesions and improving hygiene through frequent skin cleansing.

• For chronic cases, consider a nasal culture to check for staph/strep carriers.

Differential Diagnoses

• Must consider:

  • Tinea

  • Herpes

  • Burns

  • Contact dermatitis

Folliculitis

• Definition: Minor inflammation of individual hair follicles.

• Causes: Often due to Staphylococcus aureus, chemical irritation, or injury.

• Symptoms: Painful yellow pustules with hair at the center.

• Treatment:

  • Cleanse with mild soap (hexachlorophene)

  • Medications: 5% benzoyl peroxide gel, erythromycin solution 2%, clindamycin solution.

  • Oral antibiotics may be necessary depending on severity.

Furuncles (Boils)

• Definition: Deeper infection of hair follicles or cutaneous glands.

• Associated with Staphylococcus aureus (always consider MRSA).

• Symptoms: Pustular and often appear as abscesses located in hairy, high-friction areas (e.g., axilla, groin).

• Treatment:

  • Oral antibiotics: Doxycycline, sulfa, or clindamycin.

  • Apply warm moist heat 4 times a day for 30 minutes.

  • Lesions larger than 1 cm may require incision and drainage (I/D).

Carbuncles

• Definition: Group of furuncles that drain through multiple openings.

• Signs of systemic involvement: chills and fever.

• Treatment: managed like furuncles.

Cellulitis

• Definition: Acute spreading infection of skin and subcutaneous tissue.

• Symptoms: Pain, tenderness, intense erythema, chills, fever, and lymphadenopathy.

• Characteristics: The area enlarges constantly and may involve purulent or serous drainage at the inoculation site. It is not sharply demarcated (unlike erysipelas), and skin may become necrotic.

Cellulitis Management

• Most common pathogens: Streptococcus pyogenes followed by Staphylococcus aureus and Haemophilus influenzae. Consider other co-morbidities that may worsen situations (e.g., diabetes, peripheral vascular disease, immunosuppression).

• Treatment should be similar to that used for furuncles, with a focus on MRSA coverage.

• Improvement usually expected within 3-4 days, with a follow-up in 48 hours. Report worsening symptoms immediately.

Erysipelas

• Definition: A type of superficial cellulitis with sharply demarcated borders and specific symptoms.

• Common sites: Lower legs, face, and ears, often occurring after prior injury or diseases with impaired venous drainage.

• Most common cause: Streptococcus pyogenes.

• Symptoms: Rapid spread, marked erythema, warmth, local pain, elevated sharp margins, and potentially purulent drainage.

Erysipelas Management

• Prompt culture and blood cultures if systemic symptoms are present.

• Treatment similar to that for furuncles, with potential IV antibiotics for severe cases. Daily soaking to remove crusts recommended. Monitor for complications like glomerulonephritis and meningitis.

Ulcers with Secondary Infections

• Conditions: Chronic venous insufficiency, PVD ulcers at toes, pressure sores at heels, or neurogenic disorders at bony prominences.

• Management: Culture wounds for appropriate treatment.

Diabetic Foot Ulcers

• Types of infection without ulcer: Usually streptococci (groups A, B, C, D) or Staphylococcus aureus.

• Management includes culture to identify causative organisms and send to wound clinics/home care for specialized treatment.

Bites

• Human Bites: Can lead to cellulitis, treated with Augmentin or Clindamycin (if penicillin allergy), and ensure tetanus shot is administered.

• Dog and Cat Bites: Can lead to soft tissue infections; puncture wounds should be irrigated. Consider rabies shots if the dog is unvaccinated. Consult public health resources for wild animals due to rabies risk.

Spider Bites

• Brown Recluse Spider: Produces necrotic lesions, usually not painful initially. Symptoms may follow, including fever, chills; treatment needed due to potential tissue loss.

• Black Widow Spider: Venomous, known for painful bite and systemic cramping; treatment is supportive care and may require hospitalization.

Malignant Melanoma Assessment

• The ABCD(E) Features for identification:

  • A = Asymmetry

  • B = Border irregularity

  • C = Color uniformity: brown, black, red, white, blue, purple

  • D = Diameter > 6 mm at the greatest dimension

  • E = Evolving (new features)

  • F = Feel: Changes in texture (raised lesions)

• Finding more than 2 ABCD features indicates high sensitivity (100%) and specificity (98%).

Differential Diagnoses for Malignant Melanoma

• Actinic keratoses

• Basal Cell Carcinoma

• Squamous Cell Carcinoma

• Malignant Melanoma

• Dysplastic Nevi: abnormal moles

• Venous Lake: common lesions from chronic sun exposure.

Melanoma Overview

• Leading cause of death from skin disease, increasing incidence among cancers.

• Risk Factors:

  • Family history (FAMM syndrome)

  • Sun exposure

  • Hair color: blonde or red

  • Significant freckling, especially on the upper back

  • History of blistering sunburns before age 20.

  • Outdoor working history as a teenager.

  • Presence of actinic keratoses.

• Peak incidence: age 40. Having one or two risk factors increases the risk 3.5 times.

Characteristic Lesions of Melanoma

• Lesions typically raised, irregular borders, color variation from brown to dark blue.

• Subtypes are often flat (macular) freckles.

• Incisional biopsy is essential; will not cause metastasis.

• Lesions frequently pruritic, may be tender or painful.

Atypical Moles (Dysplastic Nevi)

• Features:

  • Larger than 6 mm

  • Irregular or poorly defined boundaries

  • Variegated colors

• Can be associated with familial atypical mole and melanoma syndrome (FAMM).

• Monitor for new moles more than for existing ones.

Actinic Keratosis

• Description: Focal areas of epidermal dysplasia potential to progress to squamous cell carcinoma (1 in 100).

• Manifestation: Rough lesions with a pink or flesh-colored appearance in sun-exposed areas.

• Treatment:

  • Topical 5-FU cream

  • Cryotherapy (liquid nitrogen)

Basal Cell Carcinoma

• Most common type of skin cancer, rarely metastasizes.

• Frequently occurs on sun-exposed areas, especially the head and neck.

• Symptoms: New or evolving lesions that become red, peel, bleed then scab, appearing pearly and painless.

Squamous Cell Carcinoma

• Potential to metastasize, often arises from untreated actinic keratoses.

• Description: Firm erythematous nodules, may have scale and ulceration.

• Common on sun-exposed areas.

Acronyms for Skin Lesions

• Basal Cell Carcinoma (BCC) Treatment Reminder:

  • P = Pearly papule

  • U = Ulcerating

  • T = Telangiectasia

  • O = On face/scalp/pinnae

  • N = Nodule

  • S = Slow growing

• Squamous Cell Carcinoma (SCC) Treatment Reminder:

  • N = Nodular

  • O = Opaque

  • S = Sun exposed areas

  • U = Ulcerating

  • N = Non-distinct borders

Acne Vulgaris

• Most common skin condition in the U.S., potentially leading to significant psychological trauma.

Pathophysiology of Acne

• Development starts with adrenal gland secretion stimulating sebum production from sebaceous glands.

• This process involves altered keratinization, desquamation of follicular cells, and inflammatory responses, leading to clogged pores caused by Propionibacterium acnes metabolization, which increases glycerol and free fatty acids, forming comedones.

Types of Acne

• Classification:

  • Comedonal: primary lesions.

  • Inflammatory: secondary lesions such as papular or pustular and cystic/nodulocystic forms.

American Academy of Dermatology Acne Classification System

• Severity Levels:

  • Mild:

  • Few to several papules/pustules

  • Moderate:

  • Several to many papules/pustules

  • Few to several nodules

  • Severe:

  • Numerous papules/pustules

  • Many nodules

Management of Acne

• Importance of medical history to identify aggravating factors.

• Treatment options include a wide variety of topical agents; creams may be greasy, while gels typically dry the skin.

• Factors contributing to acne include lithium, dilantin, steroids, and stress.

Topical Treatment for Acne

• Antibiotics: Recommended for mild papules or pustules:

  • Erythromycin gel

  • Clindamycin gel (available in solutions, gels, ointments, and pads)

• Combination Treatments:

  • Duac or Benzaclin: clindamycin & benzoyl peroxide combination.

  • Not all combination treatments are covered by insurance.

Benzoyl Peroxide

• Effective for all forms of papulopustular acne.

• Mechanism: Antibacterial action and drying agent.

• Side effects may include irritation and bleaching of clothing.

Topical Medications for Comedones

• Differin/Retin A/Tazorac:

  • Mechanism: Comedolytic; prevents new lesions from forming.

  • Available in creams, gels, solutions with potential side effects like irritation and photosensitivity.

Systemic Treatment for Acne

• Oral Antibiotics: For moderate to severe inflamed acne; often require 6-8 weeks of consistent treatment.

  • Common choices include tetracyclines (doxycycline, minocycline), with side effects including GI issues, phototoxicity, candidiasis, and others.

  • Erythromycin: Side effects include GI troubles; however, it is safe during pregnancy.

• Accutane/Isotretinoin: Indicated for severe nodulocystic acne unresponsive to therapy.

  • Mechanism: Decreases sebum production, antibacterial properties.

  • Available in varying doses (10, 20, 40 mg).

  • Patients must use sunscreen; side effects are common and can include dry skin, conjunctivitis, arthralgias, and increases in liver function tests; absolute contraindication in pregnancy requires reliable contraceptive use.

Oral Contraceptives for Acne

• Beneficial for women and older teens resistant to conventional therapies, particularly those with significant sebum production or comedones.

Acne Rosacea

• Definition: Chronic inflammatory disorder predominantly affecting the central face; characterized by vascular dilation.

• Primary features include erythema, papules, pustules, and tissue hyperplasia.

• Typically progressive with no known cure; avoidance of sun exposure is advised.

• Common among fair-skinned individuals, with onsets typically between ages 20-30.

Predominant Theories on Rosacea

• Theories include a vascular disorder, inflammatory response, bacterial involvement (H. Pylori), or genetic factors.

• Does not cause comedones (differentiation from acne vulgaris).

• Rhinophyma: Enlarged bulbous nose due to sebaceous gland hyperplasia.

Rosacea Symptoms and Triggers

• Symptoms: Sudden recurrences of facial flushing; dry eye syndrome may frequently occur.

• Triggers: Sun exposure, dry/oily skin, certain skin products.

Rosacea Treatment

• Topical Treatments: Metronidazole 0.75% in gel, lotion, or cream form; clindamycin or erythromycin may be alternatives.

• Systemic Management: For ocular symptoms, moderate papules, or burning/stinging; tetracycline 500 mg BID and others; dose reduction after 1-2 months if responding, with options to switch to topical treatments afterward.

Miliaria

• Definition: Occlusion of eccrine gland ducts, seen in active individuals who perspire heavily.

• Commonly confused with folliculitis; similar condition occurs in neonatal acne.

Alopecia

• Types: Non-scarring and scarring.

• Non-scarring conditions include pattern hair loss (androgenetic alopecia), thyroid disease, lupus, and drug-induced hair loss.

• Treatment options: propecia, minoxidil, and surgical hair transplants.

• Alopecia areata: Characterized by immunologically mediated hair loss, typically manifests as one or more coin-shaped areas.

Atopic Dermatitis (Eczema)

• Any eczematous condition associated with a strong family history of asthma and allergic rhinitis. Correlated with other atopic diseases.

• Diagnosis: Characterized by itching and inflammation, supported by at least three of the following: excessive dryness/scaling, location in skin folds of arms/legs.

Atopic Dermatitis Management

• Treatment focuses on avoiding irritants, minimizing skin dryness, and consistent use of emollients. For acute phases, antihistamines and corticosteroids (both topical and systemic) are often employed.

• Intermediate-potency topical corticosteroids are usually necessary during flares, switching to lowest potency afterward.

• Tacrolimus: An immunomodulator that inhibits mast cell activation; considered a non-steroidal option.

Contact Dermatitis

• Types: Irritant and allergic.

• Irritant Contact Dermatitis: Manifested through a scalded appearance, characterized by erythema, peeling skin, and a lacy border limited to the contact area.

• Allergic Contact Dermatitis: Results from delayed hypersensitivity with eruptions confined to the contact area, often due to chemicals, metals, latex, or plant exposures.

Poison Ivy/Oak

• Response: Eruption occurs 6-72 hours post-exposure; washing with soap within a timely manner (50% effective after 10 min, only 10% after 30 min, ineffective after 60 min).

• Treatment: Med-high potency corticosteroids combined with emollients; prednisone may be required for more severe reactions.

Intertrigo

• Definition: Yeast or bacterial growth in skin folds; presents with itching, burning, and stinging sensations.

• Differential Diagnosis Includes:

  • Seborrheic dermatitis

  • Psoriasis

  • Candida infections

• Treatment: Keep areas dry, reduce friction, and weight maintenance.

Seborrheic Dermatitis

• Prevalence: 3-5% of the population; onset commonly in adulthood.

• Characterized by remissions and flare-ups; commonly affects areas rich in sebaceous glands.

• Symptoms: Pruritis and dandruff; potential associations with certain conditions (AIDS, Parkinson's).

Treatment for Seborrheic Dermatitis

• Focused on decreasing skin hyper-proliferation, inflammation, and yeast presence. Treatment options include tars, hydrocortisone, ketoconazole, and possibly fluorinated corticosteroids (e.g., Lidex).

Seborrheic Keratosis

• Appearance: Stuck-on, warty lesions typically found on the back and chest; often benign but may mimic malignant melanoma.

• Referral to dermatology is common for investigation or cosmetic treatment.

Psoriasis

• Definition: Idiopathic benign epidermal hyperproliferation with genetic and environmental contributions.

• Characterization: Lifelong disease with flare-ups, often presents with thick scaled nails and heavy scaling on extremities.

• Exacerbates through stress or other environmental factors.

Psoriasis Types

• Four distinct types: Chronic plaque (most common), guttate psoriasis (commonly triggered by infections), erythrodermic and pustular psoriasis (rare).

• Nail involvement seen in around 30% of cases, presenting with distinctive nail morphologies, such as ice-pick markings or subungual hyperkeratosis.

Psoriasis Management

• Chronic nature requires ongoing therapy; avoid systemic corticosteroids, as abrupt withdrawal may precipitate flares. Treatments include emollients, topical corticosteroids, anthralin, calcipotriene, and specialized dermatological therapy including phototherapy.

Dermatophyte Infections

• Causes: Fungi penetrating hair, nails, and skin (stratum corneum). Common for pruritis and stinging sensations; transmitted via direct or indirect contact.

• Types: Tinea capitis, faciei, corporis, cruris, pedis, manum, unguium.

Tinea Corporis

• Classic “ringworm” appearance; characterized by ring-like plaques with delicate scales at margins. Differential diagnosis includes various skin conditions.

• Diagnosed via KOH test and treated with topical imidazole antifungals.

Tinea Cruris

• Appearance: Semicircular scaly plaques on the groin and inguinal folds. Managed effectively with clotrimazole cream 1%.

Tinea Pedis

• Common Name: Athlete's foot; characterized by cracking in feet and between toes. Diagnosed via KOH prep and responds to topical antifungal agents like clotrimazole 1%.

Tinea Unguium (Onychomycosis)

• Common condition (30% of skin-related mycotic infections). Characterized by toenail changes: white discoloration, crumbly subungual debris.

• Treatment includes ciclopirox nail lacquer or systemic antifungals (e.g., itraconazole, terbinafine) with a need for liver function monitoring due to hepatotoxicity.

Tinea Versicolor

• Description: Chronic yeast infection manifesting as discolored macules on the trunk and shoulders; may present with pruritis. Diagnosed with KOH prep, treated with ketoconazole shampoo or oral itraconazole.

Candida Albicans

• Typical presentations in immunocompromised states; causes “diaper rash” appearance; managed with topical nystatin.

Herpes Simplex Virus (HSV)

• Types: HSV-1 (oral infections) and HSV-2 (genital infections). Symptoms often include blistering skin and consideration of dormant virus residing in nerves.

Herpes Zoster (Shingles)

• Etiology: Reactivation of varicella-zoster virus; characterized by painful rash that follows a dermatomal distribution. Prodromal symptoms may occur including headache and malaise.

Management of Herpes Zoster

• Critical to initiate therapy within 48-72 hours post-symptom onset; options include topical moisture to lesions and systemic antiviral medications, such as valacyclovir, famciclovir, or acyclovir.

• Pain management strategies include NSAIDs and neuropathic pain agents.

Postherpetic Neuralgia (PHN)

• Pain persisting after herpes lesions resolve; management may include topical agents and moderate to potent opioids for persistent conditions.

Scabies

• Caused by mite infestation characterized by intense pruritis worsening at night. Diagnosis through skin scraping.

Scabies Management

• First-line treatments include permethrin or lindane with washing and disinfecting practices to eliminate infestation.

Pediculosis (Lice)

• Common presentations involve pruritis, typically on the scalp. Managed using permethrin or lindane treatments.

Warts

• Caused by human papillomavirus (HPV); manifestation includes various forms (e.g., verruca vulgaris) typically presenting as papules.

Warts Management

• Treatment includes salicylic acid or cryotherapy, particularly for plantar warts, while genital warts can be treated with topical medications like podofilox.

Molluscum Contagiosum

• Caused by the pox virus; particularly prevalent among HIV patients and children. Presentation involves 1-4 mm papules, often with umbilicated centers.

Pityriasis Rosea

• A benign rash with a viral origin notable for its herald patch, typically self-limiting.

Burns

• Classification of burns and treatment: first degree (no skin loss), second degree (affecting upper epidermis), and third degree (involving full thickness).

• Focused history and examination essential for managing burns.

Lichen Planus

• Chronic inflammatory reaction affecting skin and mucous membranes; presents with pruritic, purple papules with potentially genetic factors.

Dyshidrosis

• Characterized by vesicular eruptions on palms and soles, with treatment options including topical corticosteroids and oral antibiotics.

Lyme Disease

• Caused by Borrelia burgdorferi transmitted via ticks. Early recognition and treatment are crucial, especially for the erythema migrans rash type.

Antibiotic Therapy for Lyme Disease

• Criteria for starting treatment based on EM or other clear symptoms; frontline options include doxycycline or amoxicillin based on severity and presentation.

Rocky Mountain Spotted Fever

• Further characterized with risks associated with tick exposure, symptoms, and management protocols.