Skin lesions, nails, and hair

Primary Lesion

Signs/Symptoms

Etiology

Clinical Examples

Macule

Flat, circumscribed color change, <1 cm

Pigment or vascular change

Freckles, petechiae, measles rash

Papule

Elevated, solid lesion, <1 cm

Epidermal thickening or inflammation

Elevated moles, warts

Patch

Flat, irregularly shaped macule >1 cm

Same as macule but larger

Vitiligo, café-au-lait spots

Plaque

Elevated, plateau-like lesion >1 cm

Coalesced papules

Psoriasis, seborrheic keratosis

Nodule

Elevated, firm lesion >1 cm, deeper than papule

Dermal/subcutaneous infiltration

Lipoma, erythema nodosum

Wheal

Transient, raised, erythematous, irregular borders

Dermal edema from allergic reaction

Urticaria, mosquito bites

Tumor

Large (>2 cm), solid mass

Neoplastic growth

Lipoma, carcinoma

Urticaria (Hives)

Raised, itchy wheals

Histamine release

Allergic reactions

Vesicle

Small (<1 cm), fluid-filled elevated lesion

Epidermal separation

Chickenpox, herpes simplex

Bulla

Large (>1 cm), fluid-filled lesion

Blistering disorders

Bullous pemphigoid, burns

Cyst

Encapsulated, fluid or semi-solid lesion

Blocked ducts

Sebaceous cyst

Pustule

Raised lesion filled with pus

Bacterial infection

Acne, impetigo

Secondary Lesion

Signs/Symptoms

Etiology

Clinical Examples

Crust

Dried exudate on skin surface

Dried serum, blood, or pus

Scab on abrasion, impetigo

Scale

Flakes of dead skin

Excessive keratin shedding

Psoriasis, eczema

Lesion

Signs/Symptoms

Etiology

Clinical Examples

Fissure

Linear crack or break in skin

Dryness, trauma

Athlete’s foot

Erosion

Loss of superficial epidermis, moist

Trauma, rupture of vesicle

Ruptured chickenpox vesicle

Ulcer

Deeper loss of skin,  may bleed or scar

Pressure, vascular compromise

Pressure sore

Excoriation

Self-inflicted abrasion

Scratching

Scabies, insect bites

Scar

Fibrous tissue replacing injured skin

Healing after injury

Surgical scar

Atrophic Scar

Thinned, depressed scar

Loss of collagen

Striae (stretch marks)

Lichenification

Thickened, rough skin from chronic rubbing

Chronic irritation

Chronic eczema

Keloid

Raised, hypertrophic scar extending beyond injury

Excess collagen formation

After surgery or trauma

Lesion

Signs/Symptoms

Etiology

Clinical Examples

Herpes Zoster

Painful, grouped vesicles along nerve

Reactivation of varicella-zoster virus

Shingles

Erythema Migrans of Lyme Disease

Expanding bull’s-eye rash

Tick-borne Borrelia infection

Early Lyme disease

Labial Herpes Simplex (Cold Sores)

Painful vesicles on lips

HSV-1 infection

Cold sores

Lesion

Signs/Symptoms

Etiology

Clinical Examples

Basal Cell Carcinoma

Pearly, translucent papule with telangiectasia

UV radiation

Most common skin cancer

Squamous Cell Carcinoma

Scaly, erythematous patch or nodule

UV radiation, chronic irritation

Can metastasize

Malignant Melanoma

Asymmetric, irregular borders, color variation

UV exposure, genetic

Deadliest skin cancer

Hair Condition

Signs/Symptoms

Etiology

Clinical Examples

Toxic Alopecia

Sudden, diffuse hair loss

Chemotherapy, illness

Chemotherapy-induced hair loss

Tinea Capitis

Scaly patches with hair loss

Fungal infection

Scalp ringworm

Traction Alopecia

Hair loss due to pulling or tension

Hairstyles causing tension

Tight ponytails

Hirsutism

Excessive hair growth in females

Hormonal imbalance

PCOS

Nail Condition

Signs/Symptoms

Etiology

Clinical Examples

Beau Lines

Transverse grooves or depressions

Trauma, illness, systemic disease

Severe illness, chemotherapy

Splinter Hemorrhages

Thin, longitudinal red/brown lines

Trauma, endocarditis

Infective endocarditis

Onychomycosis

Thickened, brittle, discolored nails

Fungal infection

Toenail fungus

Pitting

Small depressions in nail surface

Psoriasis

Nail psoriasis

Late Clubbing

Bulbous enlargement of distal finger

Chronic hypoxia

Lung disease

Habit-Tic Dystrophy

Central longitudinal groove from repetitive trauma

Habitual picking

Nail picking behavior