​Symptoms and Signs – Differential Diagnosis of Dermatosis by Morphology
MACULES
Hypopigmented
• Halo nevus
• Leprosy
• Postinflammatory
• Sarcoidosis
• Tinea versicolor
• Tuberous sclerosis
• Vitiligo
Hyperpigmented
• Café au lait spot
• Drug eruption
• Ephelis (freckle)
• Lentigo
• Mastocytosis
• Melanoma
• Melasma
• Mongolian spot
• Nevus
• Ochronosis
• Postinflammatory
• Purpura
• Stasis dermatitis
Erythematous
• Drug eruption
• Rheumatic fever
• Secondary syphilis
• Viral exanthem

PAPULES
Isolated Papules
• Acrochordon
• Actinic keratosis
• Angiofibroma
• Angioma
• Appendageal tumors (benign or malignant)
• Bacillary angiomatosis
• Basal cell carcinoma
• Chondrodermatitis nodularis helicis
• Dermatofibroma
• Fungal infections, early
• Hemangioma
• Keratoacanthoma
• Melanoma
• Milia
• Molluscum contagiosum
• Neurofibroma
• Nevus
• Pyogenic granuloma
• Sebaceous hyperplasia
• Seborrheic keratosis
• Squamous cell carcinoma
• Wart
Papular Eruptions
• Acne rosacea
• Acne vulgaris
• Appendageal tumors (usually benign)
• Arthropod bite
• Bacillary angiomatosis
• Dermatomyositis
• Drug eruption
• Eczematous dermatitis
• Flat warts
• Folliculitis
• Granuloma annulare
• Keratosis pilaris
• Lichen nitidus
• Lichen planus
• Lichen sclerosus
• Lupus erythematosus
• Lymphoma
• Miliaria
• Molluscum contagiosum
• Neurofibromatosis
• Pediculosis corporis
• Perioral dermatitis
• Pityriasis rosea
• Polymorphous light eruption
• Pruritic urticarial papules, plaques of pregnancy
• Psoriasis
• Sarcoidosis
• Sarcoma (Kaposi’s, other)
• Scabies
• Syphilis
• Urticaria
• Vasculitis
• Venous lake
• Viral exanthem
• Xanthoma

PUSTULES
• Acne rosacea/perioral dermatitis
• Acne vulgaris
• Arthropod bite (fire ants)
• Drug eruption
• Eosinophilic folliculitis
• Erythema toxicum neonatorum
• Folliculitis
• Fungal or yeast infections, especially tinea capitis and Majocchi’s
granuloma
• Furunculosis
• Gonorrhea, disseminated
• Herpes simplex/zoster
• Impetigo
• Keratosis pilaris
• Neonatal pustulosis
• Pseudofolliculitis barbae
• Pustular psoriasis
• Pyoderma gangrenosum
• Syphilis
• Varicella

PLAQUES
• Acanthosis nigricans
• Candidiasis
• Cellulitis
• Deep fungal infections
• Dermatomyositis
• Diaper dermatitis
• Eczematous dermatitis, including lichen simplex chronicus
• Erythrasma
• Fungal infections (e.g., tinea corporis, pedis, cruris, manus)
• Granuloma annulare
• Ichthyosis
• Lichen planus
• Lichen sclerosus
• Lupus erythematosus
• Lyme disease
• Lymphoma, cutaneous T-cell
• Morphea
• Myxedema
• Necrobiosis lipoidica diabeticorum
• Paget’s disease, mammary/extramammary
• Pityriasis rosea
• Psoriasis
• Sarcoidosis
• Seborrheic dermatitis
• Sweet’s syndrome
• Syphilis
• Tinea versicolor
• Vasculitis
• Xanthelasma

NODULES AND TUMORS
• Acrochordon
• Angioma
• Appendageal tumors
• Basal cell carcinoma
• Callus/clavus
• Chondrodermatitis nodularis helicis
• Erythema nodosum
• Hidradenitis suppurativa
• Histiocytosis
• Inclusion cyst
• Kaposi’s sarcoma
• Keloid
• Lipoma
• Lymphoma, cutaneous
• Melanoma
• Metastatic carcinoma
• Neurofibroma
• Nevus
• Prurigo nodularis
• Pyogenic granuloma
• Seborrheic keratosis
• Squamous cell carcinoma
• Syphilis
• Tuberous sclerosis
• Venous lake
• Wart
• Xanthoma

VESICLES AND BULLAE
• Bullous disease in diabetes
• Bullous pemphigoid
• Burn
• Cellulitis
• Congenital syphilis
• Contact dermatitis
• Dermatitis herpetiformis
• Eczema, especially of the hand/foot
• Epidermolysis bullosa
• Erythema multiforme
• Fixed drug eruption
• Fungal infections, especially tinea pedis
• Herpes gestationis
• Herpes simplex
• Herpes zoster
• Id reaction
• Impetigo
• Insect bite reaction
• Lichen planus
• Lupus erythematosus, bullous
• Pemphigus vulgaris/foliaceus
• Porphyria cutanea tarda
• Scabies
• Staphylococcal scalded skin syndrome
• Streptococcal toxic shock–like syndrome
• Toxic epidermal necrolysis
• Varicella
• Vasculitis

EROSIONS AND ULCERS
Mouth
• Aphthae
• Avitaminosis
• Bullous pemphigoid
• Burn
• Candidiasis
• Epidermolysis bullosa
• Erythema multiforme
• Hand-foot-mouth disease
• Herpangina
• Herpes simplex
• Lichen planus
• Lupus erythematosus
• Pemphigus vulgaris
• Perlèche
• Toxic epidermal necrolysis
Genital
• Balanitis
• Candidiasis
• Chancroid
• Diaper dermatitis, severe
• Erythema multiforme
• Fixed drug eruption
• Fungal infections, tinea cruris
• Herpes simplex
• Intertrigo
• Lichen planus
• Lichen sclerosus
• Lymphogranuloma venereum
• Squamous cell carcinoma
• Syphilis
Other
• Basal cell carcinoma
• Bullous pemphigoid
• Ecthyma
• Erythema multiforme
• Ischemia
• Necrobiosis lipoidica
• Pemphigus vulgaris
• Porphyria cutanea tarda
• Pyoderma gangrenosum
• Spider bite
• Squamous cell carcinoma
• Stasis ulcer
• Toxic epidermal necrosis

DESQUAMATION
• Exfoliative dermatitis
• Kawasaki’s syndrome
• Keratolysis exfoliativa (hands and feet)
• Scarlet fever
• Scarlatiniform eruption
• Staphylococcal scalded skin syndrome
• Toxic shock syndrome (late)