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.

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Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

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Scales

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

Characteristic types of scales are:

  • Silvery-white scales: psoriasis Psoriasis Psoriasis is a common T-cell-mediated inflammatory skin condition. The etiology is unknown, but is thought to be due to genetic inheritance and environmental triggers. There are 4 major subtypes, with the most common form being chronic plaque psoriasis. Psoriasis
  • Greasy/waxy, yellowish scales: seborrheic dermatitis Seborrheic dermatitis Seborrheic dermatitis is a common chronic, relapsing skin disorder that presents as erythematous plaques with greasy, yellow scales in susceptible areas (scalp, face, and trunk). Seborrheic dermatitis has a biphasic incidence, occurring in two peaks: first in infants, then in adolescence and early adulthood. Seborrheic Dermatitis
  • Dry, diffuse, and fish-like scales on lower legs (ichthyosiform): ichthyosis vulgaris Ichthyosis Vulgaris Ichthyosis vulgaris is the most common type of keratinization disorders. The condition occurs due to an autosomal dominant mutation in the filaggrin gene, which results in skin-barrier dysfunction. Ichthyosis Vulgaris
  • Fine scales: tinea versicolor
  • Scaling in sheets: scarlet fever Scarlet fever Scarlet fever is a clinical syndrome consisting of streptococcal pharyngitis accompanied by fever and a characteristic rash caused by pyrogenic exotoxins. Scarlet fever is a non-suppurative complication of streptococcal infection that is more commonly seen in children. Incidence peaks during the winter and spring in temperate climates. Scarlet Fever
  • Follicular scales (such as keratotic plugs): keratosis pilaris
  • Gritty (sandpaper-like) scales: actinic keratosis Actinic keratosis Actinic keratosis (AK) is a precancerous skin lesion that affects sun-exposed areas. The condition presents as small, non-tender macules/papules with a characteristic sandpaper-like texture that can become erythematous scaly plaques. Actinic Keratosis (AK)
Lizard skin appearance of ichthyosis

Thickened, “lizard skin” appearance of ichthyosis vulgaris Ichthyosis Vulgaris Ichthyosis vulgaris is the most common type of keratinization disorders. The condition occurs due to an autosomal dominant mutation in the filaggrin gene, which results in skin-barrier dysfunction. 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 Impetigo Impetigo is a highly contagious superficial bacterial infection typically caused by Staphylococcus aureus (most common) and Streptococcus pyogenes. Impetigo most commonly presents in children aged 2 to 5 years with lesions that evolve from papules to vesicles to pustules, which eventually break down to form characteristic "honey-colored" crusts. 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 Atopic Dermatitis Atopic dermatitis, also known as eczema, is a chronic, relapsing, pruritic, inflammatory skin disease that occurs more frequently in children, although adults can also be affected. The condition is often associated with elevated serum levels of IgE and a personal or family history of atopy. Skin dryness, erythema, oozing, crusting, and lichenification are present. Atopic Dermatitis (Eczema): 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 Candidiasis Candida is a genus of dimorphic, opportunistic fungi. Candida albicans is part of the normal human flora and is the most common cause of candidiasis. The clinical presentation varies and can include localized mucocutaneous infections (e.g., oropharyngeal, esophageal, intertriginous, and vulvovaginal candidiasis) and invasive disease (e.g., candidemia, intraabdominal abscess, pericarditis, and meningitis). Candida/Candidiasis
    • Eczematous disease
    • Herpes simplex
Punched-out erosions with cutaneous herpes simplex virus infection

Punched-out erosions with cutaneous herpes simplex virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: Overview infection

Image: “Disseminated cutaneous Herpes Simplex Virus-1 in a woman with rheumatoid arthritis Rheumatoid arthritis Rheumatoid arthritis (RA) is a symmetric, inflammatory polyarthritis and chronic, progressive, autoimmune disorder. Presentation occurs most commonly in middle-aged women with joint swelling, pain, and morning stiffness (often in the hands). 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 Eczema Atopic dermatitis, also known as eczema, is a chronic, relapsing, pruritic, inflammatory skin disease that occurs more frequently in children, although adults can also be affected. The condition is often associated with elevated serum levels of IgE and a personal or family history of atopy. Skin dryness, erythema, oozing, crusting, and lichenification are present. Atopic Dermatitis (Eczema) (fingertips) and intertrigo.
Hand eczema with fissure

Hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand eczema Eczema Atopic dermatitis, also known as eczema, is a chronic, relapsing, pruritic, inflammatory skin disease that occurs more frequently in children, although adults can also be affected. The condition is often associated with elevated serum levels of IgE and a personal or family history of atopy. Skin dryness, erythema, oozing, crusting, and lichenification are present. Atopic Dermatitis (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 Systemic lupus erythematosus Systemic lupus erythematosus (SLE) is a chronic autoimmune, inflammatory condition that causes immune-complex deposition in organs, resulting in systemic manifestations. Women, particularly those of African American descent, are more commonly affected. 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 AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation, 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 Dermatologic examination Examination of the skin is a fundamental part of the standard physical exam. This exam consists of a thorough inspection of the skin of the entire body. The assessment focuses on identifying abnormal signs on the skin, such as the scalp, orifices, nails, and mucosal surfaces. Dermatologic Examination should be performed:

  • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the Skin and its appendages as well as mucous membranes
  • Performed with the naked eye and using a dermatoscope

Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the 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 Molluscum contagiosum Molluscum contagiosum is a viral infection limited to the epidermis and is common in children below 5 years of age. Lesions appear as grouped, flesh-colored, dome-shaped papules with central umbilication. Molluscum Contagiosum
    • Accuminate: condylomata acuminata Condylomata Acuminata Condylomata acuminata are a clinical manifestation of genital HPV infection. Condylomata acuminata are described as raised, pearly, flesh-colored, papular, cauliflower-like lesions seen in the anogenital region that may cause itching, pain, or bleeding. Condylomata Acuminata (Genital Warts)
    • 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 Eczema Atopic dermatitis, also known as eczema, is a chronic, relapsing, pruritic, inflammatory skin disease that occurs more frequently in children, although adults can also be affected. The condition is often associated with elevated serum levels of IgE and a personal or family history of atopy. Skin dryness, erythema, oozing, crusting, and lichenification are present. Atopic Dermatitis (Eczema), discoid lupus
    • Polycyclic: urticaria Urticaria Urticaria is raised, well-circumscribed areas (wheals) of edema (swelling) and erythema (redness) involving the dermis and epidermis with associated pruritus (itch). Urticaria is not a single disease but rather is a reaction pattern representing cutaneous mast cell degranulation. Urticaria (Hives)
    • Arcuate: urticaria Urticaria Urticaria is raised, well-circumscribed areas (wheals) of edema (swelling) and erythema (redness) involving the dermis and epidermis with associated pruritus (itch). Urticaria is not a single disease but rather is a reaction pattern representing cutaneous mast cell degranulation. Urticaria (Hives)
    • Linear: scabies Scabies Scabies is an infestation of the skin by the Sarcoptes scabiei mite, which presents most commonly with intense pruritus, characteristic linear burrows, and erythematous papules, particularly in the interdigital folds and the flexor aspects of the wrists. Scabies burrow, lichen nitidus
    • Reticular: livedo reticularis
    • Serpiginous: cutaneous larva migrans
    • Targetoid lesions: erythema multiforme Erythema multiforme Erythema multiforme (EM) is an acute hypersensitivity reaction characterized by targetoid skin lesions with multiple rings and dusky centers. Lesions may be accompanied by systemic symptoms (e.g., fever) and mucosal lesions (e.g., bullae). 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 Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Structure and Function of the 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 Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: Overview or varicella zoster virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: Overview).
  • 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 Pseudomonas Pseudomonas is a non-lactose-fermenting, gram-negative bacillus that produces pyocyanin, which gives it a characteristic blue-green color. Pseudomonas is found ubiquitously in the environment, as well as in moist reservoirs, such as hospital sinks and respiratory equipment. Pseudomonas wound infection (blue), vitiligo Vitiligo Vitiligo is the most common depigmenting disorder and is caused by the destruction of melanocytes. Patients present with hypo- or depigmented macules or patches which often occur on the face, hands, knees, and/or genitalia. Vitiligo (white)
  • Patch test: allergens placed on patient’s back under occlusive dressings and then checked for hypersensitivity reactions after 48 hours

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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.

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