CHAPTER 2 DIFFERENTIAL DIAGNOSIS 1. ALOPECIA, NONSCARRING Androgenetic alopecia Cosmetic treatment Tinea capitis Trichotillomania (hair pulling) Anagen arrest Telogen arrest Alopecia areata Structural hair shaft disease 2. ALOPECIA, SCARRING Trauma Tinea capitis with inflammation (kerion) Bacterial folliculitis Discoid lupus erythematosus Congenital (aplasia cutis) Lichen planopilaris Folliculitis decalvans Neoplasm 3. ANHYDROSIS Drugs (anticholinergics) Dehydration Hysteria Obstruc ion of sweat ducts (e.g., inflammation, miliaria) Local radiant heat or pressure Central n rvous system (CNS) lesions (medulla, hypothalamus, pons) Spinal cord lesions Lesions of sympathetic nerves Congenital sweat gland disturbances 4. ARTHRITIS, FEVER, AND RASH Lyme borreliosis Rocky Mountain spotted fever Parvovirus B-19 Gonococcemia Meningococcemia Secondary syphilis
20 Blisters, Subepidermal and Bullous Diseases Acute rheumatic fever Still s disease Kawasaki syndrome Vasculitic urticaria Acute sarcoidosis Rubella Familial Mediterranean fever Hyperimmunoglobulinemia D and periodic fever syndrome 5. BLISTERS, SUBEPIDERMAL Burns Porphyria cutanea tarda Bullous pemphigoid Bullous drug reaction Arthropod bite reaction Toxic epidermal necrosis Dermatitis herpetiformis Polymorphous light eruption Variegate porphyria Lupus erythematosus Epidermolysis bullosa Pseudoporphyria Acute graft-versus-host reaction Linear IgA disease Leukocytoclastic vasculitis Pressure necrosis Urticaria pigmentosa Amyloidosis 6. BULLOUS DISEASES Bullous pemphigoid Pemphigus vulgaris Pemphigus foliaceus Paraneoplastic pemphigus Cicatricial pemphigoid Erythema multiforme Dermatitis herpetiformis Herpes gestationis Impetigo Erosive lichen planus Linear IgA bullous dermatosis Epidermolysis bullosa acquisita
DIFFERENTIAL DIAGNOSIS 21 7. CUTANEOUS COLOR CHANGES Blue Cardiovascular disease Pulmonary diseases Raynaud s disease Brown Liver disease Pituitary disease Andrenocorticotropic hormone (ACTH) producing tumor (e.g., oat cell lung carcinoma) Localized: nevi, neurofibromatosis White Vitiligo Albinism Raynaud s disease Red (Erythema) Anxiety reaction Fever Polycythemia Viral exanthems Generalized urticaria Localized: inflammation, infection, Raynaud s disease Yellow Hepatitis liver disease Ch onic renal failure Anemia Hypothyroidism Increased intake of vegetables containing carotene Localized: resolving hematoma, infection, peripheral vascular insufficiency 8. CUTANEOUS INFECTIONS, ATHLETES Tinea pedis Tinea cruris Molluscum contagiosum
22 Exanthems and Fever and Rash Herpes simplex Verrucal vulgaris Folliculitis Impetigo Furuncles Otitis externa Erythrasma 9. EXANTHEMS Enterovirus Adenovirus Erythema infectiosum (fifth disease) Scarlet fever Measles Rubella Roseola exanthema Varicella Epstein-Barr virus Kawasaki syndrome Staphylococcal scalded skin Meningococcemia Rocky Mountain spotted fever 10. FEVER AND RASH Drug hypersensitivity penicillin, sulfonamides, thiazides, anticonvulsants, allopurinol Viral infection: measles, rubella, varicella, erythema infectiosum, roseola, enterovirus infection, viral hepatitis, infectious mononucleosis, acute human immunodeficiency virus (HIV) Othe infections meningococcemia, staphylococcemia, scarlet fever, typhoid fever, Pseudom nas bacteremia, Rocky Mountain spotted fever, Lyme disease, secondary syphilis, bacterial endocarditis, babesiosis, brucellosis, listeriosis Serum sickness Erythema multiforme Erythema marginatum Erythema nodosum Systemic lupus erythematosis (SLE) Dermatomyositis Allergic vasculitis Pityriasis rosea Herpes zoster
DIFFERENTIAL DIAGNOSIS 23 11. FINGER LESIONS, INFLAMMATORY Paronychia Herpes simplex type 1 (herpetic whitlow) Dyshidrotic eczema (pompholyx) Herpes zoster Bacterial endocarditis (Osler s nodes) Psoriatic arthritis 12. FLUSHING Anxiety Menopause Ingestion of hot drink Monosodium glutamate ingestion Ingestion of hot peppers Ingestion of alcoholic beverages Drugs: nicotinic acid, diltiazem, nifedipine, levodopa, bromocriptine, vancomycin, amyl nitrate Carcinoid syndrome Polycythemia, systemic mastocytosis Renal cell carcinoma Chronic myelogenous leukemia (CML) Vipoma Agnogenic flushing 13. FOOT DERMATITIS Tinea pedis Dyshydrotic eczema Tylosis (mechanically induced hyperkeratosis, fissuring, and dryness) Allergic contact dermatitis Psoriasis Peripheral vascular insufficiency Neuropathic foot ulcers (diabetes mellitus [DM], poorly fitting shoes) Acquired plantar keratoderma Sézary syndrome 14. FOOT LESIONS, ULCERATING Cellulitis Plantar wart Squamous cell carcinoma Actinomycosis (Madura foot)
24 Genital Sores and Fungal Infection Plantar fibromatosis Pseudoepitheliomatous hyperplasia 15. GENITAL SORES Trauma Herpes genitalis Syphilis Condyloma acuminatum Neoplastic lesion Chancroid Lymphogranuloma venereum Granuloma inguinale 16. GRANULOMATOUS DERMATITIDES Granuloma annulare Sarcoidosis Necrobiosis lipoidica diabeticorum Cutaneous Crohn s disease Rheumatoid nodules Annular elastolytic giant cell granuloma (actinic granuloma) Foreign body granuloma 17. HIV INFECTION, CUTANEOUS MANIFESTATIONS Viral Infection Herpes simplex Herpes zoster HIV Human papillomavirus Kaposi s sarco a (herpesvirus) Molluscum contagiosum Bacterial Infection Bacillary angiomatosis Staphylococcus aureus Syphilis Fungal Infection Candidiasis Cryptococcoses Seborrheic dermatitis
DIFFERENTIAL DIAGNOSIS 25 Arthropod Infestations Scabies Noninfectious Drug reactions Psoriasis Vasculitis Nutritional deficiencies 18. HYPERPIGMENTATION Pregnancy Drug induced (e.g., antimalarials, some cytotoxic agents) Addison s disease * ACTH- or MSH-producing tumors (e.g., oat cell carcinoma of the lung) * Hemochromatosis Malabsorption syndrome (Whipple s disease and celiac sprue) Melanoma Pheochromocytoma Porphyrias (porphyria cutanea tarda and variegate porphyria) Progressive systemic sclerosis and related conditions Psoralen and UVA (PUVA) therapy for psoriasis and vitiligo * Melanotropic hormone inject on * Arsenic ingestion 19. HYPERTRICHOSIS Systemic Illness Anorexia nervosa Hypothyroidism Malnutrition Porphyria Dermatomyositis Drugs Minoxidil Dilantin Cyclosporine Hexachlorobenzene Penicillamine *Accentuation on sun-exposed surfaces.
26 Hypopigmentation and Vasculitis/Hematologic 20. HYPOPIGMENTATION Vitiligo Tinea versicolor Atopic dermatitis Chemical leukoderma Idiopathic hypomelanosis Sarcoidosis SLE Scleroderma Oculocutaneous albinism Phenylketonuria Nevoid hypopigmentation 21. LEG ULCERS Trauma Insect bites Burns Cold injury Radiation dermatitis Factitial Excessive pressure Vascular Superficial varicosities Arteriovenous (AV) malformation Arteriosclerosis Thromboang itis obliterans Lymphatic abnormalities Incompetent perforators Cholesterol emboli Deep venous thrombosis (DVT) Vasculitis/Hematologic Sickle cell anemia Lupus anticoagulant, antiphospholipid syndrome Cold agglutinin disease Polycythemia vera Leukemia Macroglobulinemia Protein C and protein S deficiency
DIFFERENTIAL DIAGNOSIS 27 Cryoglobulinemia Thalassemia Infectious Furuncle Septic emboli Coccidioidomycosis Blastomycosis Histoplasmosis Sporotrichosis Ecthyma Leishmaniasis Metabolic Necrobiosis lipoidica diabeticorum Gout Localized bullous pemphigoid Calcinosis cutis Gaucher s disease Tumors Basal cell carcinoma Squamous cell carcinoma Melanoma Mycosis fungoides Kaposi s sarcoma Metastatic neoplasms Neuropathic Diabetic ulcers Tabes dorsalis Syringomyelia Drugs Warfarin Intravenous (IV) colchicine extravasation Hydroxyurea Methotrexate Halogens Ergotism
28 Panniculitis and Nail Clubbing Panniculitis Pancreatic fat necrosis Alpha-antitrypsinase deficiency Weber-Christian disease 22. LIVEDO RETICULITIS Emboli (subacute bacterial endocarditis [SBE], left atrial myxoma, cholesterol emboli) Thrombocythemia or polycythemia Antiphospholipid antibody syndrome Cryoglobulinemia, cryofibrinogenemia Leukocytoclastic vasculitis SLE, rheumatoid arthritis, dermatomyositis Pancreatitis Drugs (quinine, quinidine, amantadine, catecholamines) Physiologic (cutis marmorata) Congenital 23. MELANONYCHIA Pregnancy Trauma Medications (e.g., AZT, 5-fluorouracil, doxorubicin, psoralens) Nail matrix nevus HIV infection Onychomycosis Melanocyte hyperplasia Verrucae Pustular psoriasis Lichen planus Basal cell carcinoma Nail matrix melanoma Subungual keratosis Addison s disease Bowen s disease 24. NAIL CLUBBING Chronic obstructive pulmonary disease (COPD) Pulmonary malignancy Cirrhosis Inflammatory bowel disease Chronic bronchitis