Skin Lesions Overview

Skin Lesions

• A lesion is any variation from normal tissue.
• Lesions are classified as either primary or secondary.

Primary Skin Lesions

• Changes to the skin directly caused by a disease.
• Examples:
  • Macule: Flat area of color change (no elevation or depression). Example: Freckles.
  • Papule: Solid elevation less than 0.5 cm in diameter.
  • Nodule: Solid elevation 0.5 to 1 cm in diameter, extending deeper into the dermis than a papule. Example: Mole.
  • Tumor: Solid mass larger than 1 cm. Example: Squamous cell carcinoma.
  • Plaque: Flat elevated surface on skin or mucous membrane. Example: Thrush.
  • Wheal: Type of plaque, resulting from transient edema (swelling) in the dermis. Example: Intradermal skin test.
  • Vesicle: Small blister with fluid within or under the epidermis. Example: Herpesvirus infection.
  • Bulla: Large blister greater than 0.5 cm in diameter. Example: Burn.
  • Pustule: Vesicle filled with pus. Example: Acne.

Secondary Skin Lesions

• Develop from primary lesions or external forces (e.g., scratching).
• Examples:
  • Scales: Flakes of skin layer. Example: Psoriasis.
  • Crust: Dried exudate (discharge) from skin. Example: Impetigo.
  • Fissure: Cracks in the skin. Example: Athlete's foot.
  • Ulcer: Area of loss extending through the epidermis. Example: Pressure sore.
  • Scar: Excess collagen production after injury. Example: Wound healing.
  • Atrophy: Loss of some portion of skin. Example: Paralysis.

Bacterial Infections

• Acne Vulgaris:
  • Common, inflammatory condition of pilosebaceous units (oil glands).
  • Overproduction of sebum forms a keratin plug, infected by bacteria.
  • Forms comedones (pimples).
  • Common in younger individuals (12-15), triggered by puberty-related androgen surge.
  • Equally affects males and females, though males tend to have more severe cases.
  • Follicular keratinization blocks follicle.
  • Androgens cause increased sebum production.
  • Bacteria (e.g., Propionibacterium acnes) colonizes.
  • Genetics are involved.
  • Triggers: Hormonal changes, oily products, certain drugs, sweating, excessive skin contact.
  • Progression: Comedones → papules → pustules → cysts/nodules.
  • Treatment: Limit triggers, OTC/Rx medications, cleansers, topical/oral antibiotics, oral contraceptives, isotretinoin (severe cases).
• Folliculitis, Furuncle, Carbuncle: Infections of hair follicles.
  • Folliculitis: Inflammation of hair follicle.
  • Furuncle: Deeper inflammation of follicle, forming an abscess (boil).
  • Carbuncle: Group of furuncles.
  • Cause: Bacteria (mostly Staphylococcus aureus), viruses/fungi, irritation, occlusion.
  • Treatment: Topical cleansers, antibiotics. If furuncle/carbuncle, drainage required.
• Pseudofolliculitis Barbae: Ingrown beard hair, common in Black men.
  • Irritation from shaving causing hair to curl into skin.
  • Itchy, red papules/pustules.
  • Often chronic, firm papules (unlike the acute, pustular folliculitis barbae).
  • Treatment: Warm compresses, antibiotics if infection present.
• Impetigo: Superficial bacterial skin infection (deeper = ecthyma).
  • Commonly caused by Streptococcus or Staphylococcus.
  • Spread by contact/contaminated objects.
  • Vesicles/pustules, oozing, honey-colored crust.
  • Treatment: Antibiotics (topical/oral).
• Cellulitis: Bacterial infection of dermis & subcutaneous tissues.
  • Often follows skin wounds/boils.
  • Commonly caused by Staphylococcus aureus or group A Streptococcus.
  • Redness, warmth, tenderness, swelling, possible fever, chills, lymphadenopathy. Spreading red streaks possible (lymphangitis).
  • Serious if untreated; can spread to bloodstream (sepsis).
  • Treatment: Oral antibiotics (based on suspected organism).
• Erysipelas: Superficial form of cellulitis.
  • Commonly caused by various Streptococcus species.
  • Erythematous lesions with sharply demarcated, raised border (orange-peel skin).
  • Warm, swollen, painful/tender area. Lymphadenopathy and possible lymphedema.
  • Systemic symptoms possible (fever, chills, etc.).
  • Treatment: Prompt antibiotic treatment crucial to avoid sepsis or complications.

Viral Infections

• Warts, Varicella, Herpes Zoster, Herpes Simplex, Molluscum Contagiosum (see individual entries below)

Fungal Infections

• Tinea (ringworm), Candidiasis, Tinea Versicolor (see individual entries below)

Parasitic Infections

• Scabies & Pediculosis (see individual entries below)
• (Note: The following are the subtopics of the viral, fungal, and parasitic infections listed above that are not fully outlined)*

Warts (HPV related)

• Several types (common, plantar, flat, genital).
• Genital warts are highly contagious.
• Treatment varies by type; most resolve spontaneously; topical treatments are usual.
• Warts may be painful or painless, isolated or clustered.
• Can be a risk for cancer development.

Varicella Zoster (Chickenpox)

• Highly contagious viral infection, often in children.
• Spread via respiratory droplets/direct contact.
• Blisters that crust over.
• Possible complications: pneumonia, encephalitis.
• Treatment is supportive; antivirals could be suggested.
• Vaccination is available.

Herpes Zoster (Shingles)

• Reactivation of dormant Varicella-Zoster Virus (VZV).
• Often in older individuals.
• Painful vesicles in dermatomal patterns.
• Can cause post-herpetic neuralgia (PHN).
• Treatment is supportive; antivirals are used for early treatment.
• Vaccination exists.

Herpes Simplex Virus (HSV)

• Highly contagious; oral or genital herpes depending on the strain.
• Painful vesicles/pustules, crusting, recurrent/latent phases, common triggers.
• No cure; treatment focuses on reducing symptoms and transmission periods.
• HSV-1 and 2 can each infect the body's other portions (e.g., HSV-1 can infect the genitals).

Molluscum Contagiosum (MC)

• Highly contagious viral skin infection, often in children.
• Small, raised lesions with a central dimple.
• Treatment is often supportive; removal techniques could be suggested instead of letting it resolve naturally.
• Some types of warts of molluscum (or types of warts) are more common in HIV patients, other types may be more spreadable, etc.

Tinea (Ringworm)

• Fungal infection, classified by location (e.g., Tinea pedis - foot, Tinea unguium - nail, Tinea corporis - body).
• Circular rash, scaling or crumbling nails, etc.
• Treatment: Antifungal creams/powders, possibly corticosteroids (for pain/itching).

Candidiasis

• Fungal infection of skin/mucous membranes; commonly in groin, mouth, and between digits.
• May be caused by Candida albicans.
• Risk factors: immunosuppression, hyperhidrosis, incontinence, certain medications.
• Symptoms vary by location (e.g., vaginal discharge, oral patches).
• Treatment: Antifungal creams/medicated mouthwash, keeping the skin dry.

Tinea Versicolor

• Fungal infection causing discolored skin patches.
• Often in warm/humid climates.
• Hypo- or hyperpigmented patches, possibly scaling; not always painful or itchy.
• Treatment: Topical antifungal creams, oral antifungals (if needed).

Scabies

• Mite infestation.
• Severe itching, tiny red bumps/rash, especially in skin creases or folds (especially at night after a bath).
• Highly contagious – direct contact.
• Treatment: Topical creams, wash bedding/clothes.

Pediculosis (Lice)

• Several types of lice (head, body, pubic).
• Severe itching, visible lice/eggs.
• Highly contagious – direct contact/sharing items.
• Treatment: Topical creams/shampoos, re-applying after 10 days, daily combing, disinfection/vacuuming to remove fomites (infected items).

This quiz covers the classification of skin lesions, focusing on primary lesions caused directly by diseases. You'll explore various types of lesions, including macules, papules, and nodules, with examples to enhance your understanding. Test your knowledge and familiarize yourself with dermatological terminology.