Skin Lesions Overview

Skin Lesions

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

Primary Skin Lesions

• Primary lesions are changes to the skin directly caused by a disease process.
• Examples include:
  • Macule: Flat area of color change (no elevation or depression), e.g., 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, e.g., mole.
  • Tumor: Solid mass larger than 1 cm, e.g., squamous cell carcinoma.
  • Plaque: Flat elevated surface on skin or mucous membrane, e.g., thrush.
  • Wheal: A type of plaque, characterized by transient edema in the dermis, e.g., intradermal skin test.
  • Vesicle: Small blister containing fluid within or under the epidermis, e.g., herpesvirus infection.
  • Bulla: Large blister greater than 0.5 cm, e.g., burn.
  • Pustule: Vesicle filled with pus, e.g., acne.

Secondary Skin Lesions

• Secondary lesions develop from primary lesions due to external forces or factors, such as scratching.
• Examples include:
  • Scales: Flakes of skin layer, e.g., psoriasis.
  • Crust: Dried exudate on skin, e.g., impetigo.
  • Fissure: Cracks in skin, e.g., athlete's foot.
  • Ulcer: Area of complete epidermis loss, e.g., pressure sore.
  • Scar: Excess collagen production after injury, e.g., wound healing.
  • Atrophy: Loss of a portion of skin, e.g., paralysis.

Bacterial Skin Infections

• Acne Vulgaris: Common skin condition caused by obstructed and infected sebaceous glands.
  • Characterized by comedones (blackheads and whiteheads), papules, pustules, cysts, and nodules.
  • Often triggered by hormonal changes, oily products, some medications, and stress.
  • Treatment includes over-the-counter cleansers, topical and oral antibiotics, oral contraceptives to regulate hormones, and isotretinoin (Accutane) for severe cases.
• Folliculitis: Inflammation of hair follicles, often caused by bacteria (e.g., Staphylococcus aureus). Manifests through pustules around the hair follicle.
• Furuncle: Deeper inflammation of the hair follicle, forming an abscess (boil).
• Carbuncle: Group of furuncles.
• Impetigo: Bacterial infection of superficial skin layers, typically targeting children. Characterized by oozing and honey-colored crusts. Highly contagious.
• Cellulitis: Bacterial infection of dermis and subcutaneous tissues. Causes redness, warmth, tenderness, and swelling (potentially expanding). Can be serious if untreated and lead to sepsis.
• Erysipelas: Superficial form of cellulitis usually caused by Streptococcus species, marked by a sharply demarcated, raised, red lesion. Serious if untreated.

Viral Skin Infections

• Warts: Caused by human papillomavirus (HPV). Various types exist: common, plantar, flat, and genital.
  • Treatment often involves self-resolution, topical treatments (salicylic acid), cryotherapy, laser, or surgical excision.
• Varicella Zoster (Chickenpox): Highly contagious viral infection marked by itchy blisters. Potential complication: shingles.
• Herpes Zoster (Shingles): Reactivation of the varicella-zoster virus, producing a painful rash in a dermatomal pattern; typically in the elderly.
• Herpes Simplex Virus (HSV): Recurrent viral infection causing either oral (cold sores) or genital lesions. Spread by contact and often characterized by blisters. No cure.
• Molluscum Contagiosum (MC): Highly contagious viral infection causing small, round lesions, typically in children. May resolve spontaneously or require removal.

Fungal Skin Infections

• Tinea (Ringworm): Various dermatophyte fungi infect the skin. Symptoms often include a circular rash with an outer ring.
• Candidiasis: Fungal infection of skin and mucous membranes, often involving skin folds or the mouth.
• Tinea Versicolor: Fungal infection causing patches of discoloration on the skin. Often called "sun fungus" due to increased visibility in sunlight.

Parasitic Skin Infections

• Scabies: Infestation of the skin caused by the itch mite Sarcoptes scabiei. Symptoms include severe itching and rash (typically in skin folds and creases).
• Pediculosis (Lice): Infestation of lice spread by direct contact, which cause itching and visible lice or nits (eggs).

Important Note:

• Many skin infections are considered contraindications for massage until the infection is resolved. This is especially important for contagious conditions. Always refer to a doctor for diagnosis and treatment.
• Contact with lesions should be avoided to prevent spreading the infection.

This quiz covers the classification and characteristics of skin lesions, focusing on primary skin lesions. Learn about various types, including macules, papules, nodules, and more. Test your knowledge on how these lesions are defined and identified in clinical settings.