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Diagnostic Algorithm

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Diagnostic_algorithm_chart
                           
 
 
I. No apparent lesions (symptoms only)
 
    Pruritus
1. Pruritus
    Pain
2. Pain, paresthesia, anesthesia
 
 
II. Skin-colored lesions
 
     A. Epidermis intact and attached
 
          Scale absent
3. Smooth skin-colored lesions
          Scale present
4. Scaling skin-colored lesions
     B. Epidermis lifted (blisters)
 
          Blister fluid clear
5. Vesiculobullous lesions
          Blister fluid white or yellow-white
6. Pustular lesions
     C. Epidermis missing
 
          Defect shallow (epidermis)
7. Erosions
          Defect deep (dermis)
8. Ulcers
 
 
III. Non-blanchable, abnormally-colored lesions                         
 
     A. Melanin pigment
 
          Hypopigmentation
9. White lesions
          Hyperpigmentation
10. Brown or black lesions
     B. Heme pigment
 
           Non-palpable
11. Non-palpable purpuras
           Palpable
12. Palpable purpuras
     C. Other pigments
 
           Blue-gray
13. Blue-gray lesions
           Yellow
14. Yellow lesions
 
 
IV. Blanchable, red (Inflammatory) lesions
 
     A. Non-scaling red lesions
 
         Flat and flat-topped lesions
15. Vascular reactions
         Rounded and slope-shouldered lesions
16. Red papules and nodules
     B. Scaling, red lesions
 
          Epithelium intact
17. Papulosquamous lesions
          Epithelium disrupted
18. Eczematous lesions
 
 
Group 1: Pruritus
functional origin
anxiety (especially OCD), depression (esp. elderly)
systemic disorders
hepatic d. (biliary cirrhosis, obstructive d.), iron deficiency,lymphoma (Hodgkin’s), polycythemia vera, pregnancy, renal d., thyroid d.
unapparent skin conditions
AIDS, fiberglass dermatitis, mastocytosis, pediculosis (pubic, head, body), scabies, sweat retention (esp. atopics), xerosis (atopy, ichthyosis, excess bathing)
 
Group 2: Pain
absent lesions
localized chronic pain s. (glossodynia, vulvodynia, anodynia), neuralgia, post-herpetic neuralgia, reflex sympathetic dystrophy, trigeminal neuralgia
absent pain
congenital absence, leprosy, peripheral neuropathy (esp. diabetes), syringomyelia
lesion-associated
angioleiomyoma, angiolipoma, eccrine spiradenoma, glomus tumor, leiomyoma, neurilemmoma, neuroma
paresthesia
formication (“crawling” sensation in skin) in true infestation & delusions
 
Group 3. Smooth skin-colored lesions
cysts
epidermoid, mucinous, pilar, synovial
edema & pseudo-edema
angioedema, chronic genital edema, eosinophilic fasciitis, lymphedema, Melkersson-Rosenthal s., scleredema, scleromyxedema
flat & atrophic lesions
lipoatrophy, lipodystrophy, pitted keratolysis, striae
papules, nodules
BCC, chondrodermatitis nodularis, closed comedones, lipomas, molluscum contagiosum, neurofibroma, nevi (intradermal, neural), pearly penile papules, rhinophyma, scars (hypertrophic, keloid), SCC, sebaceous hyperplasia, skin tags (achrocordons), warts
rare lesions
accessory tragus, acrodermatitis chronica atrophicans, anetoderma, arsenical keratoses, basal cell nevus s., calcinosis cutis, connective tissue nevus, Cowden’s s., cylindroma, dermoid cyst, Dupuytren’s contracture, erythropoietic protoporphyria, fibroma, follicular mucinosis, knuckle pads, lipoidproteinosis, neuroma, nevus sebaceus, osteoma cutis, palmar crease keratoses, palmar/plantar keratoderma, sarcoma, syringoma, thyroglossal cyst, tophi, trichoepithelioma
 
Group 4. Scaling skin-colored lesions
papules & nodules
actinic keratosis, callous, corn, keratoacanthoma, SCC, seborrheic keratosis, verruca
plaques & disseminated disease
epidermal nevus, ichthyosis, nevus sebaceus, porokeratosis of Mibelli, post-inflammatory desquamation & exfoliation, tinea manum, tinea pedis, xerosis
uncommon, rare
acrokeratoelastoidosis, acrokeratosis verruciformis, Cowden’s s., disseminated actinic porokeratosis, elastosis perforans serpiginosum, elephantiasis nostra verrucosa, epidermodysplasia verruciformis, hyperkeratosis lenticularis perstans, knuckle pads, Kyrle’s d., perforating folliculitis, stucco keratoses, surfer’s nodule
 
Group 5. Vesiculobullous lesions
vesicular, common
dyshidrosis (pompholyx), herpes simplex, herpes zoster, id reaction, molluscum contagiosum, scabies, tinea pedis (vesicular), vesicular insect bites
vesicular, uncommon & rare
chronic bullous disease of childhood, dermatitis herpetiformis, eczema herpeticum & vaccinatum, Grover’s d., hand foot & mouth d., herpes gestationis, hidrocystoma, incontinentia pigmenti, intraepidermal IgA disease, linear IgA d., lymphangioma circumscriptum, pityriasis lichenoides
bullous, common
burns, bullous impetigo, contact dermatitis, friction blisters
bullous, uncommon
bullous disease of dialysis, bullous hemorrhagic pyoderma gangrenosum, chronic bullous disease of children, coma blisters, diabetic bullous d., epidermolysis bullosa, epidermolysis bullosa acquisita, erysipeloid, erythema multiforme, fixed drug eruption, linear IgA disease, milker’s nodule, necrotizing fasciitis, orf, pemphigoid, pemphigus, porphyria
 
Group 6. Pustular lesions
common
acne vulgaris, acne conglobata, candidiasis, erythema toxicum neonatorum, folliculitis, keratosis pilaris, perioral dermatitis, pyoderma faciale, rosacea, stye
uncommon
acne keloidalis, acne necrotica miliaris, acrodermatitis continua, Behçet’s d., bowel bypass s., chloracne, chronic gonococcemia, Crohn’s d., dissecting cellulitis, eosinophilic folliculitis, folliculitis decalvans, hidradenitis suppurativa, impetigo herpetiformis, infantile acral pustulosis, intraepidermal neutrophilic IgA dermatosis, myeloma, pityrosporum folliculitis, psoriasis, pustular dyshidrosis, pustular psoriasis, pustulosis palmaris et plantaris, steroid acne, subcorneal pustular dermatosis, transient neonatal pustular melanosis, ulcerative colitis
 
Group 7. Erosions
common
candidiasis, excoriation, impetigo, unroofed vesiculobullous & pustular lesions
uncommon
acrodermatitis enteropathica, glucagonoma s., SSSS, TEN
Group 8. Ulcers
common
aphthous ulcers, arteriosclerotic, BCC, chondrodermatitis nodularis, decubitus, gangrenous ulcers, neuropathic, SCC, stasis, traumatic
uncommon
actinomycosis, amebiasis, anthrax, aplasia cutis congenita, Bart’s s., chancroid, Churg & Strauss d., Crohn’s d. of skin, dental sinus, ecthyma, factitial, focal dermal hypoplasia, fungal infection, hemoglobinopathies, herpes infection, chronic (immunosuppressed), congenital sinus, granuloma inguinale, keratoacanthoma, leishmaniasis, lymphoma, lymphomatoid papulosis, mycobacterial infection, nocardiosis, panniculitis, polyarteritis nodosum, pyoderma (blastomycosis-like), pyoderma (malignant), pyoderma gangrenosum, septicemic ulcers, spider bite, syphilis (primary), temporal arteritis, tularemia, Wegener’s d.
 
Group 9. White lesions
papules
acne vulgaris, calcinosis cutis, hair casts, keratosis pilaris, lichen nitidus, milia, molluscum contagiosum, nits, scars, sebaceous gland hyperplasia, tophus, white piedra
patches, plaques
albinism, atrophie blanche, chemically induced hypomelanosis, Degos’ d., halo nevus, hypomelanosis of Ito, hypopigmentation, idiopathic guttate hypomelanosis, leprosy, lichen sclerosis et atrophicus, morphea, piebaldism, pinta, pityriasis alba, poliosis, post-inflammatory sarcoid, scleroderma, tinea versicolor, tuberous sclerosis, vitiligo, yaws
mucous membrane
biting trauma, candidiasis, leukoplakia, lichen planus, lupus erythematosus, secondary syphilis, white hairy leukoplakia
 
Group 10. Brown-black lesions
generalized
Addison’s disease, cancer chemotherapeutic agents, dyskeratosis congenita, exfoliative erythrodermatitis, heavy metals, hemochromatosis, ichthyosis, MSH-related pigmentation in endocrine & malignant d., phenothiazines, porphyria, progeria, Rothmund-Thomson s., scleroderma, Whipple’s d., Wilson’s d.
macules, papules, nodules
acanthosis nigricans, acrochordon (skin tag), angiokeratoma, black piedra, Bowenoid papulosis, dermatofibroma, dermatosis papulosis nigra, freckles, lentigo, lentigo maligna, lentigo maligna melanoma, nevus (compound, junctional, intradermal), nevus (dysplastic), open comedone, pigmented BCC, seborrheic keratosis, urticaria pigmentosa
patches & plaques
acanthosis nigricans, acral lentiginous melanoma, Albright’s s., alkaptonuria, atrophoderma of Pasini & Pierini, Becker’s nevus, Berloque (furocoumarin) dermatitis, café-au-lait macules, café-au-lait like birthmarks, chloasma (melasma), confluent & reticulated papillomatosis, congenital pigmented nevus, Dowling-Degos’ disease, erythema ab igne, erythrasma, fixed drug eruption, incontinentia pigmenti (late), lentigo maligna, lentigo maligna melanoma, linear nevoid hypermelanosis, morphea, pigmentary demarcation lines (Futcher’s line), poikilodermatous pigmentation, postinflammatory hyperpigmentation, tinea nigra palmaris, tinea versicolor
 
Group 11. Non-palpable purpura
ecchymotic
actinic purpura, amyloidosis, angioimmunoblastic lymphadenopathy, anticoagulant therapy, calciphylaxis, DIC, Gardner-Diamond s., intravascular coagulation defects (platelets, erythrocytes, coagulation proteins), necrotizing fasciitis, scurvy, steroid purpura, superficial hemorrhagic pyoderma gangrenosum, trauma, vasculitis (polyarteritis nodosa, lymphomatoid granulomatosis)
petechial (primarily)
bacteremia (staphylococcal, meningococcal, bacteria endocarditis), benign pigmented purpuras, black-dot toes & heels, dysproteinemia (cryoglobulinemia), histiocytosis X, hydrostatic petechiae (stasis), intravascular coagulation defects, medication (thiazides)
 
Group 12. Palpable purpura
bacteremia
bacteria endocarditis, meningococcal, staphylococcal
non-vasculitic
angiokeratoma, cherry angioma, Kaposi’s sarcoma, pyogenic granuloma
rickettsia
RMSF, typhus
venulitis, arteritis
dysproteinemia, Henoch-Schönlein purpura, leukocytoclastic vasculitis, (hypersensitivity vasculitis, rheumatoid vasculitis)
 
Group 13. Blue-gray lesions
macules, patches
atrophoderma of Pasini & Pierini, erythema dyschromicum perstans, fixed drug eruption, heliotrope eyelids (dermatomyositis), hemochromatosis, medication (antimalarials, gold, metals, minocycline, phenothiazines, silver), Mongolian spot, Nevus of Ito & Ota, osteoma cutis, tattoo (asphalt, foreign body, graphite, lead), venous lake
papules, nodules
acroangiodermatitis (arteriovenous fistula, pseudo-Kaposi’s disease), angiosarcoma, angiolymphoid hyperplasia, blue nevus, collagen vascular d., Glomus tumor, granuloma annulare, hemangioma (esp. cavernous & verrucous), hidrocystoma, Kaposi’s sarcoma (esp. classic), leukemia cutis, lichen planus, lymphoma cutis (esp. B-cell), pyogenic granuloma
 
Group 14. Yellow lesions
macules, patches
amyloidosis, carotenemia, Fordyce condition (mucous membranes), jaundice, keratoderma of palms & soles, necrobiosis lipoidica diabeticorum, pseudoxanthoma elasticum, solar elastosis, xanthomas (palmar, plantar)
papules, plaques, nodules
amyloidosis, colloid milium, cyst, histiocytic lesion, juvenile xanthogranuloma, mastocytoma, nevus sebaceus, sebaceous hyperplasia, solar elastosis, tophus, xanthelasma, xanthoma (tendinous, tuberous)
 
Group 15. Vascular reactions
diffuse, morbilliform
GVH, Kawasaki d., scarlet fever, SSSS, TEN (early erythema chronic migrans,), toxic shock s., viral exanthem (erythema infectiosum, roseola, rubella, rubeola)
gyrate, serpiginous, annular
creeping eruption elastosis perforans serpiginosum, erythema annulare centrifugum, erythema gyratum repens, erythema multiforme, granuloma annulare, sarcoid, SCLE
livedo pattern
antiphospholipid s. (lupus anticoagulant, Sneddon’s s.), cholesterol emboli, cutis marmorata telangiectatica, erythema ab igne, erythema infectiosum, large vessel vasculitis, poikiloderma (Civatte, collagen vascular disease, cutaneous lymphoma), polyarteritis
macular localized
acrocyanosis, BCC, Bowen’s d., face (lupus erythematosus, dermatomyositis, seborrheic dermatitis, photosensitivity reaction), fixed drug eruption, groin (intertrigo, erythrasma, tinea cruris, seborrheic dermatitis), hand (erythromelalgia, liver d., hereditary redness of the palm, chemotherapy), pernio, tinea versicolor
plaques
arthropod assault, cellulitis, erysipelas, erysipeloid, erythema elevatum diutinum, erythema multiforme, erythema nodosum, fixed drug eruption, granuloma faciale, hypocomplementemic vasculitis, juvenile rheumatoid arthritis, nodular vasculitis, panniculitis, PUPPP, relapsing polychondritis, Sweet’s s., Well’s cellulitis
telangiectatic
angioma serpiginosum, ataxia telangiectasia, erythema ab igne, essential telangiectasia, poikilodermatous conditions, radiodermatitis, telangiectasia of collagen vascular disease (CREST s.), TMEP, unilateral nevoid telangiectasia
transient erythema
anaphylactic reaction, contact urticaria, cutis marmorata, dermographism, erythema marginatum urticaria, flushing (carcinoid, emotional, mastocytosis, medications, pheochromocytoma), physical urticaria
 
Group 16. Red papules and nodules
papules
arthropod assault, cherry angioma, CNCH, coral & marine animal contact, diaper granuloma, elastosis perforans serpiginosum, eosinophilic folliculitis, eruptive xanthoma, foreign body granuloma, Gianotti-Crosti s., Gottron’s papules, granuloma annulare, Grover’s d., Kaposi’s sarcoma, lymphomatoid papulosis, mites, multicentric reticulohistiocytosis, papular urticaria, pityriasis lichenoides, pityriasis rosea, pityrosporum folliculitis, pyogenic granuloma, sarcoid, scabies, secondary stye & hordeolum, syphilis
nodules, plaques
acne conglobata, acne cyst, angiolymphoid hyperplasia with eosinophilia, angiosarcoma, arthropod assault, carbuncle, cylindroma, dissecting cellulitis, erythema elevatum diutinum, erythema nodosum, furuncle, granuloma annulare, hemangioma, hidradenitis suppurativa, inflamed cyst, Kaposi’s sarcoma, lupus erythematosus, lymphocytic infiltrate of Jessner, lymphoma & leukemia cutis, milker’s nodule, mycobacterial infection, myiasis, nodular vasculitis (erythema induratum), orf, panniculitis, polymorphous light eruption, pseudolymphoma, pyoderma faciale, rheumatoid nodules, sarcoma, sporotrichosis, Sweet’s s., vasculitis (esp. polyarteritis nodosum)
 
 Group 17. Papulosquamous lesions
papules
lichen planus, pityriasis lichenoides, pityriasis rosea, psoriasis, secondary syphilis, viral exanthem
plaques
actinic reticuloid, Basex s., Bowen’s d., Darier’s d., ichthyosis, ILVEN, keratosis lichenoides chronica, lichen striatus, lupus erythematosus, mycosis fungoides, Pagetoid reticulosis, parapsoriasis, pellagra, photosensitivity eruptions, pityriasis rubra pilaris, psoriasis, Reiter’s s., superficial BCC, tinea (capitis, corporis, cruris, pedis)
 
Group 18. Eczematous lesions
prominent excoriation
atopic dermatitis, dermatitis herpetiformis, dyshidrotic eczema, exfoliative erythrodermatitis, lichen simplex chronicus, neurodermatitis, scabies, stasis dermatitis
minimal excoriation
acrodermatitis enteropathica, actinic reticuloid, allergic contact dermatitis, asteatotic eczema, autoeczematization, Darier’s d., external otitis, glucagonoma s., Hailey-Hailey d., histiocytosis X, ILVEN, impetigo, infectious eczematoid dermatitis, irritant contact dermatitis, juvenile palmar-plantar dermatitis, Leiner’s d., lichen striatus, nummular eczema, Paget’s d., perioral dermatitis, photosensitivity s., seborrheic dermatitis, winter itch, xerotic eczema
 

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