​Symptoms and Signs – Differential Diagnosis  of Dermatosis by Region
SCALP
Papules/Plaques
• Actinic keratosis
• Appendageal tumor
• Cyst
• Hemangioma
• Lichen planopilaris
• Lupus erythematosus
• Melanoma
• Nevus
• Seborrheic keratosis
Nodules
• Actinic keratosis
• Appendageal tumor
• Basal cell carcinoma
• Cyst
• Hemangioma
• Kerion
• Metastatic carcinoma
• Nevus
• Prurigo nodularis
• Seborrheic keratosis
Eruptions
• Contact dermatitis
• Dissecting cellulitis
• Eczema
• Folliculitis
• Herpes zoster
• Pediculosis capitis
• Psoriasis
• Seborrheic dermatitis
• Tinea capitis
Alopecias
• Alopecia areata
• Anagen effluvium
• Androgenic alopecia
• Discoid lupus erythematosus
• Hypervitaminosis A
• Lichen planopilaris
• Syphilis
• Systemic disease
• Telogen effluvium
• Tinea capitis
• Traction/chemical alopecia
• Trichotillomania
FACE
Isolated Papules
• Acrochordon
• Actinic keratosis
• Angioma
• Appendageal tumors
• Basal cell carcinoma
• Cyst
• Dermatosis papulosa nigra
• Hemangioma
• Keratoacanthoma
• Lentigo maligna
• Milia
• Nevus
• Sebaceous hyperplasia
• Seborrheic keratosis
• Solar lentigo
• Squamous cell carcinoma
• Telangiectasia
• Venous lake
• Xanthelasma
Eruptions
• Acne rosacea
• Acne vulgaris
• Adenoma sebaceum
• Dermatomyositis
• Eczema, including contact dermatitis
• Erysipelas
• Favre-Racouchot (comedones in actinically damaged skin)
• Fifth disease
• Herpes simplex/zoster
• Impetigo
• Lupus erythematosus
• Lymphocytoma cutis
• Melasma
• Pemphigoid/pemphigus
• Perioral dermatitis
• Photodrug eruption
• Pityriasis alba
• Postinflammatory hypopigmentation
• Psoriasis
• Sarcoidosis
• Scleroderma
• Seborrheic dermatitis
• Steroid rosacea
• Syphilis
• Tinea corporis
• Urticaria, angioedema
• Warts, especially flat or molluscum
ORAL MUCOSA
See also Dermatosis by Morphology, Erosions, and Ulcers.
• Kaposi’s sarcoma
• Leukoplakia
• Melanoma
• Mucous cysts
• Oral hairy leukoplakia
• Oral melanotic macule
• Pyogenic granuloma
• Verruca
AXILLA
• Acanthosis nigricans
• Acrochordon
• Axillary freckling in neurofibromatosis
• Bullous pemphigoid
• Contact dermatitis
• Epidermal inclusion cyst
• Erythrasma
• Fox-Fordyce disease
• Fungal or yeast infections
• Hailey-Hailey disease
• Hidradenitis suppurativa
• Intertrigo
• Pediculosis corporis
• Pseudoxanthoma elasticum
• Scabies
• Striae distensae
• Trichomycosis axillaris
HANDS AND FEET
Isolated Papules
• Actinic keratosis
• Arsenical keratosis
• Basal cell carcinoma
• Callus/clavus
• Felon
• Keratoacanthoma
• Melanoma
• Nevus
• Painful fat herniations
• Pyogenic granuloma
• Solar lentigo
• Squamous cell carcinoma
• Warts
Eruptions
• Acute or chronic paronychia
• Cutaneous larva migrans (feet)
• Dermatomyositis
• Drug eruption
• Eczema, including contact dermatitis
• Emboli
• Epidermolysis bullosa
• Erythema multiforme
• Granuloma annulare
• Hand-foot-mouth disease
• Herpetic whitlow
• Hyperhidrosis
• Juvenile plantar dermatosis
• Keratolysis exfoliativa
• Lichen planus (wrists, ankles)
• Lupus erythematosus
• Pitted keratolysis (feet)
• Pityriasis rubra pilaris
• Porphyria cutanea tarda
• Psoriasis
• Reiter’s syndrome
• Rocky Mountain spotted fever
• Scabies
• Scleroderma
• Syphilis
• Tinea pedis, manus
• Viral exanthems
• Vitiligo
GENITALIA/INGUINAL
• Acrochordons
• Acrodermatitis enteropathica
• Angiokeratoma
• Balanitis
• Bowen’s disease
• Candidiasis
• Chancroid
• Condylomata acuminata
• Contact dermatitis
• Diaper dermatitis
• Erythema multiforme
• Erythrasma
• Fixed drug eruption
• Folliculitis
• Furunculosis
• Herpes simplex/zoster
• Hidradenitis suppurativa
• Intertrigo
• Kawasaki’s syndrome
• Lichen planus
• Lichen sclerosus
• Lichen simplex chronicus
• Lymphogranuloma venereum
• Molluscum contagiosum
• Paget’s disease, extramammary
• Pearly penile papules
• Pediculosis pubis
• Perianal streptococcal cellulitis
• Pinworm
• Pityriasis rubra pilaris
• Psoriasis
• Reiter’s syndrome
• Scabies
• Seborrheic dermatitis
• Squamous cell carcinoma
• Syphilis
• Tinea cruris
PHOTODISTRIBUTED
• Dermatomyositis
• Lupus erythematosus
• Pellagra
• Photodrug eruption
• Polymorphous light eruption
• Porphyria cutanea tarda