The Basics: Skin Types, Definitions, and Differentials

Abstract

This chapter serves as a reference tool for identifying and describing skin lesions in regards to color, distribution, configuration, borders, and shape. In addition, dermatological disorders are categorized based on primary lesion(s) to help in the differential diagnosis.

Table 1.1 Skin types

Skin Lesion Description

Describing skin lesions and findings is an important skill in order to effectively communicate with colleagues. The description should include primary lesion terminology with information in regards to color, distribution, color, configuration, borders, and shape along with any secondary lesions if present. The tables below define terms that are used to describe lesions.

Table 1.2 Primary Lesions

Table 1.3 Terminology of other descriptive lesions

Table 1.4 Terminology for describing color, shape, texture, and pattern of lesions

Table 1.5 Secondary lesions

Differential Diagnoses Based on Primary Lesions

Primary Lesions

Macules and Patches

White/Hypopigmented Macules

Alezzandrini’s syndrome (vitiligo)

Amelanotic melanoma or melanoma with regression

Amino acid disorders (e.g. Phenylketonuria)

Atrophic lichen planus

Chediak-Higashi syndrome

Chemical leukoderma (i.e. phenols)

Halo nevus without nevus

Hypomelanosis of Ito

Hypopigmented mycosis fungoides

Idiopathic guttate hypomelanosis

Incontinentia pigmenti – fourth stage

Lichen sclerosis et atrophicus

Morphea

Nevus anaemicus

Nevus depigmentosus

Oculocutaneous albinism

Partial albinism (piebaldism)

Pityriasis alba

Pityriasis Lichenoides chronica

Progressive macular hypomelanosis

Post inflammatory hypopigmentation

Radiation dermatitis

Scarring discoid lupus erythematosus

Syphilis, yaws, pinta

Thyroid disease

Tinea versicolor

Tuberculoid leprosy

Tuberous sclerosis

Vitiligo

Vogt-Koyanagi syndrome (vitiligo)

Waardenburg’s syndrome (piebaldism)

Brown Macules

Acanthosis nigricans

Adrenocorticotropic hormone (ACTH) administration

Addison’s disease

Agminated Nevus

Albright’s syndrome

Ataxia-telangiectasia

Becker’s nevus

Berloque dermatitis

Bloom’s syndrome

Cafe au lait spots

Congenital nevus

Drug (i.e. arsenic, psoralen, chlorpromazine, minocycline)

Dyskeratosis congenita

Ephelides

Erythema dyschromicum perstans (initial lesions)

Erythromelanosis follicularis faciei et colli

Exogenous Ochronosis

Fanconi’s syndrome

Fixed drug eruption

Galli-Galli disease

Hemochromatosis

Junctional nevus

Lentigo maligna

Lentigo

Lichen amyloidosis

lncontinentia pigmenti - third stage

Macular amyloidosis

Melasma

Mongolian spot

Moynahan’s syndrome (LEOPARD)

Nevus of Ota/Ito

Nevus spilus

Peutz-Jeghers syndrome

Pigmented contact dermatitis (Riehl’s melanosis)

Phytophotodermatitis (i.e. limes, celery, fig)

Postinflammatory hyperpigmentation

Seborrheic keratosis (early)

Speckled lentiginous nevus

Traumatic tattoo

Tuberous sclerosis

Urticaria Pigmentosa

Von Recklinghausen’s Neurofibromatosis

Erythema/Red Macules

Acral erythema (palms and soles – due to chemotherapy)

Carcinoid

Drug hypersensitivity syndrome (sulfa, anticonvulsants, allopurinol, minocycline)

Erysipelas

Figurate erythemas –

• Erythema multiforme

• Erythema annulare centrifugum

• Erythema marginatum

• Erythema chronica migrans

• Erythema gyratum repens

• Erythema dyschromicum perstans

Fixed drug eruption

Necrolytic migratory erythema (glucagonoma)

Physical agents –

• Heat (erythema ab igne, first degree burn)

• Cold

• Trauma

Postinflammatory erythema

Scarlet fever

Staph/strep toxic shock syndrome

Toxic erythema (drug, infection, systemic disease)

Ultraviolet exposure

Urticaria

Urticaria pigmentosa

Vascular nevi

Viral exanthems (i.e. nterovirus, hepatitis, mononucleosis, measles, roseola, erythema infectiosum)

Atrophic Patches

Acrodermatitis chronica atrophicans

Anetoderma

Aplasia cutis congenita

Atrophic lichen planus

Atrophie blanche

Atrophoderma of Pasini and Pierini

Chronic graft vs. host reaction

Extramammary Paget’s

Focal dermal hypoplasia

Follicular atrophoderma

Leprosy

Lichen sclerosus et atrophicus

Lupus erythematosus

Macular atrophy

Malignant atrophic papulosis (Degos disease)

Meischer’s granuloma (giant cell elastophagocytosis)

Morphea

Necrobiosis lipoidica diabeticorum

Nevus lipomatosus

Sarcoidosis

Steroid application or injection

Striae

Syphilis, tertiary

Papules and Plaques

Red Papules

Arthropod reaction

Bacteremia (i.e. meningococcal, gonococcal)

Disseminated candidiasis

Eruptive xanthomas

Folliculitis (i.e. bacterial, candidal, eosinophilic, fungal, viral)

Gianotti-Crosti syndrome (children-acral only; hepatitis B, EBV)

Guttate Psoriasis

Hot tub folliculitis (Pseudomonas)

Lymphomatoid papulosis

Miliaria rubra/profunda

Papular drug eruption

Pityriasis lichenoides et varioliformis acuta

Scabies

Secondary Syphilis

Viral exanthem

Annular Papules

Alopecia mucinosa

Arthropod reaction

Basal cell carcinoma

Contact dermatitis

Dermatophyte infections

Elastosis perforans serpiginosa

Erythema elevatum diutinum

Granuloma annulare

Leiomyoma

Lichen planus

Lymphocytic infiltrate of Jessner

Lymphocytoma cutis

Lymphoma/leukemia cutis

Leishmaniasis

Mastocytoma

Meischer’s granuloma (giant cell elastophagocytosis)

Necrobiosis lipoidica diabeticorum

Nummular eczema

Sarcoidosis

Syphilis, secondary or tertiary

Hyperkeratotic Papules

Acquired perforating dermatosis (Kyrle’s disease)

Acrokeratosis verruciformis of Hopf

Actinic keratosis

Arsenic ingestion

Confluent reticulate papillomatosis (Gougerot-Carteaud)

Cutaneous horn

Darier’s disease

Elastosis perforans serpiginosa (elastic fibers)

Epidermal nevi (Inflammatory Linear Verrucous Epidermal Nevus – ILVEN)

Follicular lichen planus

Incontinentia pigmenti (verrucous stage)

Keratoacanthoma

Keratosis pilaris

Keratosis punctata

Lichen spinulosus

Lichen striatus

Lithium ingestion

Localized epidermolytic hyperkeratosis

Perforating folliculitis

Phrynoderma

Pityriasis rubra pilaris

Porokeratosis

Psoriasis

Reactive perforating collagenosis (collagen fibers)

Seborrheic keratosis

Verruca vulgaris/plana

Lichenoid Papules

Bowenoid papulosis (genitals)

Cowden’s disease (lichenoid papules on the face)

Gianotti-Crosti (acral lichenoid papules)

Lichen amyloidosis

Lichen myxedematosus

Lichen nitidus

Lichen planus

Lichen sclerosus et atrophicus

Lichen simplex chronicus

Lichen spinulosus

Lichen striatus

Lichenoid actinic keratosis

Lichenoid drug eruption

Lichenoid seborrheic keratosis

Papular granuloma annulare

Sarcoidosis

Secondary syphilis

Tuberculosis cutis lichenoides (lichen scrofulosorum)

Verruca plana

Linear Papules

Contact dermatitis

Granuloma annulare

Herpes zoster (usually vesicular)

Ichthyosis hystrix

Insect bites

Jellyfish stings (usually vesicular)

Koebnerization (i.e. lichen planus, psoriasis, verruca vulgaris)

Linear epidermal nevus

Lichen planus

Linear porokeratosis

Lichen nitidus

Lichen striatus

Linear verruca vulgaris/plana

Nevus unius lateris

Nevus verrucosus

Sporotrichosis

Red Plaques

Actinic keratosis

Acute hemorrhagic edema of infancy

Alopecia mucinosa

Amelanotic melanoma

Bowen’s disease

Discoid lupus

Eosinophilic granuloma

Erysipelas

Erythema elevatum diutinum

Fixed drug eruption

Granuloma annulare

Granuloma faciale

Kaposi’s sarcoma

Langerhan’s cell histiocytosis (intertriginous areas)

Leishmaniasis

Leprosy

Leukemia/lymphoma cutis

Lupus vulgaris

Lymphocytic infiltrate of Jessner

Malignant angioendotheliomatosis

Mycosis fungoides

Polymorphous light eruption

Pseudolymphoma of Spiegler-Fendt

Psoriasis

Rosacea

Sarcoidosis

Seborrheic dermatitis

Superficial basal cell carcinoma

Sweet’s syndrome

Annular Plaques

Actinic granuloma (annular elastolytic giant Cell Granuloma)

Alopecia mucinosa

Basal cell carcinoma

Bowen’s disease

Cutaneous larva migrans

Deep fungal infection

Discoid lupus erythematosus

Eosinophilic annular erythema

Erysipeloid

Erythema annulare centrifugum

Erythema chronicum migrans (Lyme disease)

Erythema multiforme

Factitial dermatitis

Fixed drug eruption

Granuloma annulare

Granuloma faciale

Leprosy

Leukemia/lymphoma cutis

Lichen planus

Lichen sclerosus et atrophicus

Lichen simplex chronicus

Lupus vulgaris

Lymphocytic infiltrate of Jessner

Lymphocytoma cutis

Morphea

Mycosis fungoides

Necrobiosis lipoidica diabeticorum

Necrolytic migratory erythema

Nummular eczema

Papular mucinosis

Parapsoriasis

Polymorphous light eruption

Porokeratosis of Mibelli

Psoriasis

Sarcoidosis

Seborrheic dermatitis

Syphilis, secondary

Tinea

Urticaria

Nodules and Tumors

Table 1.6 Dermal tumors and nodules

Red Nodules

Table 1.7 Red Nodules

Subcutaneous Nodules without Epidermal Changes

Table 1.8 Subcutaneous nodules without epidermal changes

Painful Tumors

Adiposis dolorosa (Dercum’s disease)

Angiolipoma

Blue rubber bleb nevus

Chondrodermatitis nodularis helicis

Cutaneous endometriosis

Eccrine spiradenoma

Endometriosis

Foreign body granuloma

Glomus tumor

Granular cell tumor

Leiomyoma

Neurilemmoma

Neuroma

Osteoma cutis

Pustules

Acne vulgaris

Acute febrile neutrophilic dermatosis

Anthrax

Atypical mycobacteria

Benign familial pemphigus (Hailey-Hailey disease)

Cellulitis

Cowpox

Deep fungal infections (i.e. actinomycosis, nocardia, sporotrichosis)

Dermatitis herpetiformis

Disseminated candidiasis

Ecthyma

Erysipeloid

Erythema toxicum neonatorum

Folliculitis (bacterial, candidal, eosinophilic, fungal, steroid use)

Furuncle, carbuncle

Gonococcemia

Herpes simplex/zoster

Hot tub folliculitis (Pseudomonas)

Impetigo

Impetigo herpetiformis

Infected contact dermatitis

Infected dyshidrotic eczema

Intertrigo

Miliaria

Miliaria rubra

Monkeypox

Multiple arthropod bites

Pemphigus foliaceus, IgA pemphigus

Perleche

Pustular psoriasis

Rhinoscleroma

Scabies

Smallpox

Steroid acne

Subcorneal pustular dermatosis (Sneddon-Wilkinson)

Sycosis barbae

Tinea

Transient neonatal pustular melanosis

Varicella

Vesicles and Bullae

Arthropod reaction

Behçet’s syndrome

Benign familial pemphigus (Hailey-Hailey disease)

Benign mucous membrane pemphigoid

Bullosa diabeticorum

Bullous fixed drug eruption

Bullous impetigo

Bullous lichen planus

Bullous pemphigoid

Burn, second degree

Cat scratch disease

Chronic bullous dermatosis of childhood

Coma blisters

Congenital ichthyosiform erythroderma

Contact dermatitis

Dermatitis herpetiformis

Discoid lupus erythematosus

Drug reaction (bullous)

Dyshidrotic eczema (pompholyx)

Epidermolysis bullosa

Erythema elevatum diutinum

Erythema multiforme

Erythema toxicum neonatorum

Factitial

Factitial dermatitis

Friction blister

Gonococcemia, meningococcemia

Gunther’s disease

Hand, foot, and mouth disease

Herpes gestationis

Herpes simplex/zoster

Hydroa vacciniforme

Incontinentia pigmenti

Lymphangioma/seroma

Miliaria

Necrolytic migratory erythema (glucagonoma)

Neonatal pustular melanosis

Pemphigus vulgaris, foliaceus, lgA

Photoallergic drug eruption

Polymorphous light emption

Porphyria cutanea tarda

Pressure urticaria

Pseudoporphyria

Pyoderma gangrenosum

Rickettsialpox

Rocky mountain spotted fever

Scabies

Smallpox

Smallpox (variola)

Staph scalded skin syndrome

Stevens-Johnson syndrome

Subcorneal pustular dermatosis (Sneddon-Wilkinson)

Sweet’s syndrome

Tinea corporis

Tinea manuum/pedis

Toxic epidermal necrolysis

Transient acantholytic dermatosis (Grover’s disease)

Urticaria pigmentosa/mastocytoma

Varicella

Vesicular id reaction

Viral infection (simplex, zoster, varicella, smallpox)

Weber-Cockayne syndrome

Ulcers

Table 1.9 Ulcers and associated diseases

Necrotic Lesions

Bromoderma

Behçet’s disease

Calciphylaxis

Chemical agents - coumadin, intravenous adrenergics, chemotherapeutic agents, cocaine levamisole

Disseminated intravascular coagulation

Dysproteinemias – cryoglobulins, cryofibrinogens

Embolization –thrombus, fat

Envenomation – brown recluse spider, snakes, scorpion

Factitial

Granulomatosis with polyangiitis

Infection – bacterial (i.e. anthrax, streptococcus, atypical mycobacteria, mengiococcus, rickettsial, treponemal), fungal (i.e. nocardia, actinomycosis, sporotrichosis, histoplasmosis, cryptococcus, blastomycosis, tuberculosis), viral (i.e. smallpox, varicella)

Physical agents – heat, cold, trauma, pressure, electrical, radiation

Primary vascular – artetiosclerosis, thromboangiitis, diabetes

Pyoderma gangrenosum

Vasculitis secondary to connective tissue disease – SLE, polyarteritis, rheumatoid arthritis, temporal arteritis, Wegener’s, CREST

Vasospastic – Raynaud’s, hypertensive ulcer, ergot poisoning, arterial or venous drug extravasation

Vascular Lesions

Non-palpable Purpura (Petechial and Ecchymotic)

Capillaritis

• Schamberg’s purpura- “cayenne pepper” pattern on legs

• Majocchi’s purpura (purpura annularis telangiectoidess)

• Gougerot-Blum – purpuric lichenoid dermatitis

• Ducas and Kapetanakis – eczematoid purpura

Coagulopathies – disseminated intravascular coagulation, liver disease, anticoagulant therapy

Drug – anticoagulants, phenacetin, steroids, NSAIDs

Hypersensitivity vasculitis

Infections – Subacute Bacterial Endocarditis, Rock Mountain Spotted Fever (RMSF), meningococcemia, gonococcemia, Weil’s disease (leptospirosis), various hemorrhagic fevers including Ebola and Marburg, congenital rubella, echovirus, toxoplasmosis, cytomegalovirus

Livedo reticularis

Resolving erythemas

Scurvy (perifollicular)

Senile purpura

Systemic disease – diabetes, Cushing’s disease, uremia

Thrombocythemia

Thrombocytopenia – ITP, TIP, bone marrow depression

Toxic venoms

Traumatic purpura

Waldenström’s hyperglobulinemic purpura

Palpable Purpura (Cutaneous Vasculitis)

• I. Primarily Cutaneous

Cutaneous polyarteritis nodosa

Erythema elevatum diutinum

Hypersensitivity vasculitis/idiopathic allergic vasculitis/anaphylactoid purpura (all likely the same entity) – usually due to infection, drug, or systemic disease

Pityriasis lichenoides et varioliformis acuta (PLEVA) (lymphocytic as opposed to leukocytoclastic)

Sweet’s syndrome

Urticarial vasculitis/erythema multiforme

• II. Cutaneous and systemic – usually leukocytoclastic unless noted

  Abnormalities in blood viscosity

  • Cold agglutinins  – viral pneumonia, SLE, lymphoma

  • Cryofibrinogens  – abnormality in clotting and degradation – seen in viral diseases (especially hepatitis)

  • Cryoglobulinemia  – cold exposure, multiple myeloma, SBE, leukemia, RA, liver disease, hepatitis, disseminated cancer, syphilis, mononucleosis, primary idiopathic

  • Hypergammaglobulinemic purpura

  Carcinoma : lymphoma, leukemia, lung and bowel cancer, Hodgkin’s disease, multiple myeloma

  Collagen vascular diseases (usually a livedo pattern): rheumatoid arthritis, SLE, dermatomyositis, Sjörgen’s, inflammatory bowel disease

  Drug (usually lymphocytic): ASA, NSAIDs, sulfa, chloroquine, penicillin, quinidine, thiazides, TB drugs, phenothiazines

  Infection: streptococcus, Rock Mountain Spotted Fever, GC, meningiococcemia, Tuberculosis, syphilis, viruses (especially hepatitis)

  Other:

  • Henoch-Schöenlein purpura  – abdominal pain, mucosal bleeding, hematuria, arthralgias, headache

  • Polyarteritis nodosa and other related granulomatous arteritides – allergic granulomatosis, Wegener’s

Telangiectasia

Primary

Ataxia telangiectasia

Essential telangiectasia

Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu)

Nevus telangiectaticus

Poikilodermatous diseases (Bloom’s syndrome, Cockayne’s syndrome, Dyskeratosis congenita

Poikiloderma atrophicans vasculare, Rothmund-Thomson syndrome)

Spider angioma

Telangiectasia macularis eruptiva perstans

Xeroderma pigmentosum

Secondary

Actinic damage

Basal cell carcinoma

Chronic topical steroid application

Collagen vascular disease

Drugs (estrogen, corticosteroids)

Keloid

Liver disease

Melasma

Necrobiosis lipoidica

Poikiloderma of Civatte

Pregnancy

Radiation dermatitis

Rosacea