Secondary Skin Lesions

The identification and classification of a patient’s skin lesions are important steps in the diagnosis of any skin disorder. Primary lesions represent the initial presentation of the disease process. Secondary lesions develop from irritated or manipulated primary lesions and/or manifestations of disease progression. The key features of skin lesions include type, morphology, color, shape, arrangement, and distribution. A comprehensive examination of the skin, appendages, and mucous membranes is done, with the type of procedure performed depending on the suspected diagnosis.

Last update:

Table of Contents

Share this concept:

Share on facebook
Share on twitter
Share on linkedin
Share on reddit
Share on email
Share on whatsapp

Scales

Scales are dry or greasy masses of keratin that represent thickened stratum corneum.

Characteristic types of scales are:

  • Silvery-white scales: psoriasis
  • Greasy/waxy, yellowish scales: seborrheic dermatitis
  • Dry, diffuse, and fish-like scales on lower legs (ichthyosiform): ichthyosis vulgaris
  • Fine scales: tinea versicolor
  • Scaling in sheets: scarlet fever
  • Follicular scales (such as keratotic plugs): keratosis pilaris
  • Gritty (sandpaper-like) scales: actinic keratosis
Lizard skin appearance of ichthyosis

Thickened, “lizard skin” appearance of ichthyosis vulgaris

Image: “In vivo confocal microscopy of pre-Descemet corneal dystrophy associated with X-linked ichthyosis: a case report” by BMC Ophthalmology. License: CC BY 4.0

Crust

  • Dried exudate of body fluids (blood, pus, or sebum) on an area of damaged skin
  • The color of the crust gives clues to its cause:
    • Yellow crusts arise from sebum.
    • Yellow-green crusts are formed from pus.
    • Red or brown crusts are formed from blood (hemorrhagic crust).
  • Shape may indicate previous lesion:
    • Round/oval: former vesicle/bulla or pustule
    • Linear: excoriations
  • May be thin, delicate, and easy to remove or thick and deeply attached to the skin.
  • Examples include:
    • Tinea capitis
    • Impetigo
    • Scabs on healing wounds
Crusted, nonbullous impetigo on the upper extremity of a pediatric patient

Crusted, nonbullous impetigo on the upper extremity of a pediatric patient

Image: “Diagnosis of Atopic Dermatitis: Mimics, Overlaps, and Complications” by Siegfried EC, Hebert AA. License: CC BY 4.0

Erosion

  • Discontinuity of the skin exhibiting incomplete loss of the epidermis
  • Does not penetrate below the dermal–epidermal junction and, thus, heals without scarring
  • Lesion is moist, well-circumscribed, and depressed.
  • Can be traumatic, inflammatory, or due to infectious skin diseases
  • Examples include: 
    • Tinea pedis
    • Candidiasis
    • Eczematous disease
    • Herpes simplex
Punched-out erosions with cutaneous herpes simplex virus infection

Punched-out erosions with cutaneous herpes simplex virus infection

Image: “Disseminated cutaneous Herpes Simplex Virus-1 in a woman with rheumatoid arthritis receiving infliximab: a case report” by Justice EA, Khan SY, Logan S, Jobanputra P. License: CC BY 2.0

Excoriation

Excoriation is a linear abrasion produced by mechanical means (scratching, rubbing, or picking) that usually involves only the epidermis but can reach the papillary dermis.

Excoriation disorder secondary to skin picking

Excoriation disorder secondary to skin picking

Image: “Derma me” by Boogafreak/Vatadoshu. License: Public Domain

Ulcer

  • A breakdown of the skin exhibiting complete loss of the epidermis and often portions of the dermis and subcutaneous fat
  • Ulcers always result in a scar.
  • Causes include:
    • Trauma (e.g., heat, cold, electrical, chemical)
    • Infections (e.g., bacterial, viral, fungal)
    • Chronic venous stasis
    • Vascular compromise (e.g., decubitus ulcers and peripheral arterial disease)
Ulcer from chronic venous stasis

Ulcer from chronic venous stasis

Image: “Interaction between a regenerative matrix and wound bed in nonhealing ulcers: results with 16 cases” by Motolese A, Vignati F, Brambilla R, Cerati M, Passi A. License: CC BY 3.0

Fissure

  • A linear crack in the skin that is usually narrow and extends through the epidermis into the dermis
  • Caused by external tension or excessive drying of the skin
  • Fissures commonly occur at the angles of the mouth (angular cheilitis).
  • Examples also include eczema (fingertips) and intertrigo.
Hand eczema with fissure

Hand eczema with fissure between first and second digit

Image: “Occupational protein contact dermatitis: two case reports” by Rocha J, Pereira T, Sousa-Basto A, Brito C. License: CC BY 3.0

Atrophy

  • A loss of tissue that can be epidermal, dermal, or subcutaneous
  • Atrophic skin usually appears thin, translucent, and wrinkled.
  • Produced by long-term sun exposure, aging, and some inflammatory and neoplastic skin diseases, such as systemic lupus erythematosus and cutaneous T-cell lymphoma
  • Atrophy also may occur as a result of the long-term use of topical corticosteroids.
Atrophic skin of the left hip seen in granulomatous slack skin

Atrophic skin of the left hip seen in granulomatous slack skin (T-cell lymphoma)

Image: “Granulomatous slack skin T-cell lymphoma: an important differential diagnosis with giant cell tumor of soft tissue” by Adriano AR, Lima TS, Battistella M, Bagot M. License: CC BY 4.0, cropped by Lecturio.

Lichenification

  • Thickening and hyperpigmentation of the skin resulting from repeated rubbing
  • Normal skin/skinfold markings become more prominent.
  • Examples include:
    • Lichen simplex chronicus
    • Prurigo
    • Atopic dermatitis

Approach to Diagnosing Skin Conditions

Complete medical history

  • Underlying conditions (e.g., autoimmune disorders, diabetes)
  • Accompanying symptoms (e.g., burning, itching)
  • Medications
  • Allergies
  • Evolution and duration of skin lesion, aggravating and alleviating factors
  • Social, sexual, and travel history

Physical examination

A general physical examination as well as a focused dermatologic examination should be performed:

  • Skin and its appendages as well as mucous membranes
  • Performed with the naked eye and using a dermatoscope

Skin features and commonly associated skin conditions and/or lesions to consider:

  • Texture: 
    • Raised: papule, plaque, nodule, cyst, wheal
    • Depressed: ulcer, atrophy
    • Flat: macule, patch
    • Fluid-filled: vesicle, bulla, furuncle, pustule, abscess
  • Morphology: 
    • Dome-shaped: hemangioma
    • Flat-topped: verruca plana
    • Umbilicated: molluscum contagiosum
    • Accuminate: condylomata acuminata
    • Verrucous: verruca vulgaris
    • Pedunculated: acrochordon (skin tag)
  • Diameter: varies per condition
  • Composition: fluid-filled, pus-filled, blood-filled, or solid
  • Borders: regular or irregular, flat or raised
  • Color: hypopigmentation, hyperpigmentation, or erythema
  • Arrangement: grouped (herpetiform)/scattered
  • Configuration: 
    • Annular: tinea corporis, granuloma annulare
    • Round/discoid/nummular: eczema, discoid lupus
    • Polycyclic: urticaria
    • Arcuate: urticaria
    • Linear: scabies burrow, lichen nitidus
    • Reticular: livedo reticularis
    • Serpiginous: cutaneous larva migrans
    • Targetoid lesions: erythema multiforme
    • Whorled: incontinentia pigmenti
Secondary skin lesions

Secondary skin lesions:
Erosion: discontinuity of the skin with incomplete loss of the epidermis without penetration below the dermal–epidermal junction
Ulcer: complete loss of the epidermis and portions of the dermis and subcutaneous fat resulting in a scar
Fissure: narrow linear crack/split in the skin, extending through the epidermis into the dermis
Atrophy: loss of tissue that can be epidermal, dermal, or subcutaneous with appearance of thin, translucent, and/or wrinkled skin surface
Excoriation: linear abrasion produced by mechanical means (scratching, rubbing, or picking)
Crust: dried exudate of body fluids (blood, pus, or sebum) on an area of damaged skin
Scale: dry or greasy masses of keratin representing thickened stratum corneum
Lichenification: thickening and hyperpigmentation of the skin resulting from repeated rubbing

Image by Lecturio.

Diagnostic procedures

  • Skin biopsy (lesion excised, saucerized, or taken by punch biopsy)
  • KOH preparation: 
    • Lesion is scraped and placed on a glass microscope slide, where it is treated with 1 or 2 drops of a solution of 10%–20% KOH.
    • If fungal infection suspected
  • Tzanck smear: cytologic technique when vesicular conditions are noted (infections from herpes simplex virus or varicella zoster virus).
  • Diascopy: determines whether lesion will blanch under pressure, differentiating a hemorrhagic (does not blanch) from a fluid-filled lesion
  • Wood’s light: 
    • Uses 360-nm UV light to evaluate lesions
    • Conditions: erythrasma (coral pink color), Pseudomonas wound infection (blue), vitiligo (white)
  • Patch test: allergens placed on patient’s back under occlusive dressings and then checked for hypersensitivity reactions after 48 hours

References

  1. Amerson, E. H., Burgin, S., Shinkai, K. (2019). Fundamentals of clinical dermatology: morphology and special clinical considerations. In Kang, S., et al. (Eds.). Fitzpatrick’s Dermatology, 9th ed. McGraw-Hill.
  2. Bolognia, J. L., Schaffer, J.V ., Cerroni, L. (2018). Basic Principles of Dermatology, 4th ed. Edinburgh. Elsevier.

Study on the Go

Lecturio Medical complements your studies with evidence-based learning strategies, video lectures, quiz questions, and more – all combined in one easy-to-use resource.

Learn even more with Lecturio:

Complement your med school studies with Lecturio’s all-in-one study companion, delivered with evidence-based learning strategies.

🍪 Lecturio is using cookies to improve your user experience. By continuing use of our service you agree upon our Data Privacy Statement.

Details