• Acne vulgaris, erythematous papule vs. Rosacea, erythematous papule

• Acute discoid lupus erythematosus vs. Subacute cutaneous lupus erythematosus

• Allergic contact dermatitis vs. Irritant contact dermatitis

• Allergic (leukocytoclastic) vasculitis vs. Septic vasculitis

• Alopecia areata vs. Trichotillomania

• Alopecia of discoid lupus erythematosus vs. Alopecia of lichen planus

• Amputation neuroma secondary to supernumerary digit vs. Acquired digital fibrokeratoma

• Angiolymphoid hyperplasia with eosinophilia vs. Angiosarcoma

• Angiolymphoid hyperplasia with eosinophilia vs. Kimura's disease

• Apocrine (clear-cell) hidradenoma vs. Eccrine (poroid) hidradenoma

• Apocrine mixed tumor vs. Eccrine mixed tumor

• Atrophic lichen planus vs. Atrophic discoid lupus erythematosus

• Common baldness vs. Telogen effluvium

• Darier's disease (keratosis follicularis) vs. Grover's disease (transient acantholytic dermatosis)

• Dermatitis herpetiformis vs. Bullous pemphigoid

• Dermatofibroma vs. Dermatofibrosarcoma protuberans

• Dermatofibroma vs. Desmoplastic Spitz's nevus

• Dermatofibroma, hemorrhagic papulo-nodule vs. Kaposi's sarcoma, hemorrhagic papulo-nodule

• Dermatofibroma with "monster" cells vs. Malignant fibrous histiocytoma

• Dilated pore vs. Pilar sheath acanthoma

• Discoid lupus erythematosus vs. Dermatomyositis

• Discoid lupus erythematosus vs. Polymorphous light eruption

• Epidermolytic hyperkeratosis vs. Plane wart

• Erythema multiforme vs. Fixed drug eruption

• Erythema multiforme vs. Graft-versus-host disease, acute phase

• Erythema multiforme vs. Pityriasis lichenoides et varioliformis acuta (Mucha-Habermann disease)

• Erythema multiforme vs. Toxic shock syndrome

• Erythema nodosum vs. Nodular vasculitis

• Erythroderma of psoriasis vs. Erythroderma of mycosis fungoides

• Granular-cell tumor vs. Xanthoma

• Granuloma annulare vs. Eruptive xanthoma

• Granuloma annulare vs. Necrobiosis lipoidica

• Granuloma annulare, interstitial type vs. Interstitial granulomatous dermatitis with arthritis

• Guttate psoriasis vs. Guttate (dermatosis) parapsoriasis

• Guttate psoriasis vs. Seborrheic dermatitis

• Herpes simplex vs. Vaccinia

• Ichthyosis vulgaris vs. X-linked ichthyosis

• Infundibular cyst vs. Isthmus-catagen cyst

• Infundibulo-folliculo-sebaceous cystic hamartoma vs. Steatocystoma

• Insect "bite" vs. Lymphomatoid papulosis

• Insect "Bite," Superficial vs. Pruritic Urticarial Papules and Plaques of Pregnancy (PUPPP)

• Interstitial granuloma annulare vs. Interstitial mycosis fungoides

• Junctional melanocytic nevus vs. Melanoma in situ on sun-damaged skin of a face

• Keloid vs. Hypertrophic scar

• Keratoacanthomatous verruca vulgaris vs. Verrucous keratoacanthoma

• Leukocytoclastic vasculitis vs. livedo vasculitis

• Leukokeratosis vs. Leukoplakia

• Lichen amyloidosis vs. Colloid milium

• Lichen nitidus vs. Lichen striatus

• Lichen planus vs. Lichen planus-like keratosis

• Lichen planus vs. Lichenoid discoid lupus erythematosus

• Lichen planus vs. lichenoid drug eruption

• Lichen planus vs. Lichenoid secondary syphilis

• Lichen planus-like keratosis vs. Solar keratosis with lichenoid infiltrate of lymphocytes

• Lichen sclerosus et atrophicus vs. Chronic radiation dermatitis

• Lichen sclerosus et atrophicus vs. Superficial morphea

• Lichen simplex chronicus vs. Hypertrophic lichen planus

• Lichenoid purpura (of Gougerot and Blum) vs. Mycosis fungoides (plaque stage)

• Lupus erythematosus profundus vs. Panniculitis-like T-cell lymphoma

• Lupus profundus vs. Morphea profundus

• Lymphocytoma cutis with lymphoid follicles vs. Follicular-cell lymphoma

• Lymphomatoid papulosis vs. Mycosis fungoides, plaque

• Metastatic carcinoma from a breast vs. Morpheiform basal-cell carcinoma

• Morphea, late stage vs. Collagenous nevus

• Mucha-Habermann vs. Lymphomatoid papulosis

• Mucha-Habermann disease vs. Secondary syphilis

• Mycosis fungoides, papular/plaque stage vs. Adult T-cell leukemia/lymphoma, papular stage

• Mycosis fungoides, plaque vs. Histiocytosis X, plaque

• Necrobiosis lipoidica vs. Necrobiotic xanthogranuloma

• Nevus verrucosus vs. Acanthosis nigricans

• Nodular fasciitis vs. Malignant fibrous histiocytoma

• Nodular scabies vs. Lymphomatoid papulosis

• Nodular vasculitis vs. Subcutaneous polyarteritis nodosa

• Pagetoid Bowen's disease vs. Extramammary Paget's disease

• Pale-cell acanthoma vs. Psoriasis, plaque expression

• Papular Mucinosis vs Interstitial Granuloma Annulare

• Pemphigus vulgaris vs. Benign familial chronic pemphigus Hailey-Hailey disease

• Pemphigus vulgaris vs. Grover's disease, pemphigus vulgaris-like variant

• Perforating Folliculitis vs. Elastosis Perforans Serpiginosa

• Photoallergic dermatitis vs. Phototoxic dermatitis

• Pityriasis lichenoides acuta vs. Pityriasis lichenoides chronica

• Pityriasis rosea vs. Guttate dermatosis (mycosis fungoides)

• Porokeratotic epidermal nevus vs. Inflammatory linear verrucous epidermal nevus

• Pretibial myxedema vs. Scleromyxedema

• Pruritic urticarial papules and plaques of pregnancy vs. Herpes gestationis, urticarial stage

• Pseudocarcinomatous hyperplasia (as in a deep fungal infection) vs. Squamous-cell carcinoma

• "Pseudolymphoma," B-cell type vs. Malignant lymphoma, B-cell type

• Psoriasis vs. Nummular dermatitis

• Psoriasis vs. Pityriasis rubra pilaris

• Psoriasis on volar skin vs. Dyshidrotic dermatitis

• Pyogenic granuloma vs. Bacillary angiomatosis

• Pyogenic granuloma, fully developed vs. Kaposi's sarcoma, nodular

• Regression of lichen planus-like keratosis vs. Regression of primary cutaneous melanoma

• Scleroderma (morphea) vs. Scleredema (Buschke)

• Sebaceous hyperplasia vs. Nevus sebaceus of Jadassohn

• Seborrheic keratosis, acanthotic type vs. Eccrine poroma

• Solar keratosis vs. Bowen's disease

• Spitz's nevus, compound type vs. Melanoma

• Spongiotic dermatitis with simulation of Pautrier's collections vs. Mycosis fungoides with Pautrier's collections

• Staphylococcal scalded skin syndrome (expression of toxic epidermal necrolysis) vs. Erythema multiforme (expression of toxic epidermal necrolysis)

• Subcutaneous granuloma annulare vs. Rheumatoid nodule

• Surface of dermatofibroma affiliated with follicular germs vs. Surface of superficial basal-cell carcinoma

• Syringocystadenoma papilliferum vs. Hidradenoma papilliferum

• Trichoadenoma vs. Microcystic adnexal carcinoma

• Trichoblastoma, small nodular type vs. Basal-cell carcinoma, small nodular type

• Trichoblastoma, small nodular type vs. Trichoblastoma, large nodular type

• Trichoblastoma, trichoepitheliomatous type vs. Trichoblastic (basal-cell) carcinoma, nodular type

• Trichoepithelioma vs. Infundibulocystic basal-cell carcinoma

• Trichotillomania (developed fully) vs. Traction alopecia (end stage)

• Tuberculoid leprosy vs. Sarcoidosis

• Urticaria vs. Urticarial lesions of bullous pemphigoid

• Urticarial reaction to an arthropod assault vs. Urtica

• Verruca vulgaris vs. Verrucous solar keratosis

• Verrucous seborrheic keratosis vs. verrucous epidermal nevus

• Xanthogranuloma vs. Necrobiotic xanthogranuloma

• Xanthogranuloma vs. Reticulohistiocytic granuloma

• Xanthomatous dermatofibroma vs. Xanthomatous malignant fibrous histiocytoma