Seborrheic dermatitis (Figure 1) is a common, chronic, superficial inflammatory disease of the scalp, face, and central chest. Erythematous, often greasy, plaques favor hair-bearing areas. Pruritus of the scalp is common. Disease in infants is commonly known as cradle cap.

• Differential diagnosis: atopic dermatitis, allergic or irritant contact dermatitis, tinea capitis, psoriasis
• Treatment: shampoos containing zinc pyrithione, selenium sulfide, salicylic acid, coal tar, or ketoconazole, and topical cortico steroids

Seborrheic keratoses (Figure 2), the most common benign cutaneous neoplasms, are warty, age-related hyperkeratotic plaques which may appear anywhere on the body, most commonly the trunk. Rarely, seborrheic keratoses may indicate an underlying adenocarcinoma of the gastrointestinal tract if they appear suddenly in great numbers (sign of Leser-Trélat).¹

• Differential diagnosis: verruca vulgaris (warts), epidermal nevus, melanocytic nevi, melanoma
• Treatment: no treatment is necessary. If the plaques are pruritic, they may be removed by curettage or cryotherapy

Urticaria (Figure 3), or hives, are most often caused by medication (commonly penicillin or other antibiotics, sulfa drugs, aspirin) or food (shellfish, nuts, chocolate), less so by infection. Hives are pruritic, edematous, evanescent wheals that resolve within 24 hours. Acute urticaria may last four to six weeks.²

• Differential diagnosis: erythema multiforme, systemic lupus erythematosus, bullous pemphigoid, mastocytosis
• Treatment: elimination of known causes, antihistamines (H₁ and H₂ blockers)

Erythema multiforme (Figure 4), a cutaneous hypersensitivity reaction, is usually caused by infection (herpes simplex virus or Mycoplasma pneumoniae) and less commonly by drug sensitivity (sulfonamides, barbiturates, or antibiotics). Macules, papules, plaques, vesicles, or bullae, often with a targetoid or iris appearance, occur on the skin, often with an acral distribution (extremities), and mucosal surfaces.

• Differential diagnosis: urticaria, drug eruption, bullous pemphigoid
• Treatment: oral antiviral agents, eg, famciclovir and valacyclovir, for herpes infection; discontinuation of possible causative medications; supportive care

Vitiligo (Figure 5) is characterized by a focal or generalized distribution of depigmented macules and patches. Disease commonly occurs periorificially (mouth, orbits, vagina, anus) or at sites of trauma (hands, elbows, knees). The disorder is often associated with thyroid disease, diabetes mellitus, pernicious anemia, or Addison's disease.

• Differential diagnosis: tinea versicolor, pityriasis alba, postinflammatory hypopigmentation, hypopigmented mycosis fungoides
• Treatment: topical cortico steroids, phototherapy, depigmentation

Erythema nodosum (Figure 6), the most common type of panniculitis, is characterized by painful, reddened nodules on the shins, occasionally elsewhere. The most common cause of erythema nodosum is a streptococcal pharyngitis; less common causes include drug sensitivity (sulfonamides, oral contraceptives) and a variety of diseases, most often inflammatory bowel disease and sarcoidosis.

• Differential diagnosis: nodular vasculitis, other types of panniculitis
• Treatment: elimination of known causes, bed rest, nonsteroidal anti-inflammatory medications

Exfoliative dermatitis (Figure 7), or erythroderma, is an inflammatory skin disease characterized by generalized erythema and scaling, often with pruritus, malaise, and chills. The most common causes are preexisting skin diseases, eg, psoriasis, atopic eczema, and drug hypersensitivity, less commonly cutaneous lymphoma (T-cell type).

• Treatment: treatment is based on the underlying disorder

Blistering Diseases:

Pemphigus vulgaris (Figure 8) is a chronic, debilitating blistering disease characterized by painful mucosal erosions and flaccid blisters that yield characteristic erosions. Ninety percent of patients have mucosal disease, and erosions may outnumber intact bullae. Biopsy reveals characteristic acantholysis, and the deposition of immunoglobulin G (IgG) within the epidermis by immunofluorescence. Morbidity and mortality are significant, even with treatment.

• Differential diagnosis: bullous pemphigoid, Stevens-Johnson syndrome, epidermolysis bullosa acquisita
• Treatment: systemic corticosteroids, various steroid-sparing immunosuppressants

Bullous pemphigoid (Figure 9), the most common bullous disease, is characterized by pruritic, large, tense blisters which are often pruritic. In contrast to pemphigus vulgaris, mucosal disease is rare. Biopsy reveals subepidermal bullae and deposition of IgG at the dermal-epidermal junction by immunofluorescence. With treatment, affected patients have a good prognosis.

• Differential diagnosis: bullous systemic lupus erythematosus, epidermolysis bullosa acquisita, cicatricial pemphigoid, dermatitis herpetiformis
• Treatment: topical and systemic corticosteroids, tetracycline, niacinamide, various steroid-sparing immunosuppressants

Dermatitis herpetiformis (Figure 10) is a chronic, intensely pruritic, papulovesicular disease characterized by symmetric groups of vesicles, papules, and wheals on the elbows, knees, scalp, and buttocks. Biopsy reveals dermal papillary microabscesses of neutrophils and the deposition of IgA at the dermal-epidermal junction by immunofluorescence. Most patients have an asymptomatic gluten-sensitive enteropathy, or less commonly, thyroid disease.

• Differential diagnosis: linear IgA dermatosis, bullous pemphigoid, bullous lupus erythematosus
• Treatment: dapsone, sulfapyridine, gluten-free diet

Epidermolysis bullosa acquisita (Figure 11) is a bullous disease characterized by skin fragility, milia (small cysts), scarring alopecia, and nail dystrophy. Skin disease typically follows trauma and occurs primarily on the hands, feet, elbow, and knees. Immunofluorescence is similar to bullous pemphigoid—IgG deposition at the dermal-epidermal junction.³

• Differential diagnosis: bullous pemphigoid, bullous systemic lupus erythematosus
• Treatment: topical and systemic corticosteroids

Cutaneous metastases (Figures 12a, 12b), occurring in less than 5% of patients with metastatic cancer, usually reflect the most prevalent types of cancer in the general population, eg, cancers of the breast, lung, or gastrointestinal tract. Cutaneous metastases are usually skin-colored to violaceous nodules that appear in close proximity to the primary neoplasm, most commonly occurring on the head, neck and trunk.

• Differential diagnosis: pilar or epidermal inclusion cyst, adnexal tumor, neurofibroma, lipoma
• Treatment: depends on the primary neoplasm and overall prognosis

Paget's disease of the breast (Figure 13) is a unilateral, eczematous plaque of the nipple and areola. Disease is nearly always associated with an underlying intraductal carcinoma of the breast. Extramammary Paget's disease is typically a persistent, eczematous plaque of the anogenital area whose morphology strongly resembles Paget's disease of the breast. Extramammary Paget's diseas is associated with an underlying adnexal (apocrine) carcinoma or an underlying cancer of the genitourinary tract or distal gastrointestinal tract in approximately 50% of affected patients.

• Differential diagnosis: allergic or irritant contact dermatitis, psoriasis, dermatophyte infection
• Treatment: surgical excision

Acanthosis nigricans (Figure 14), smooth, velvet-like, hyperkeratotic plaques of intertriginous areas, eg, the groin, axillae, neck, may indicate an underlying adenocarcinoma, especially of the gastrointestinal tract. Malignant acanthosis nigricans has a sudden onset and more extensive distribution, eg, the face and dorsal and palmar surfaces of the hands. Other more common causes of acanthosis nigricans are obesity, insulin-resistant diabetes, and medications, eg, systemic corticosteroids, nicotinic acid, diethylstilbestrol, and isoniazid (INH).

• Differential diagnosis: confluent and reticulated papillomatosis, Dowling-Degos' disease
• Treatment: treatment of underlying disorder, including removal of malignant tumor

Gardner's syndrome is an autosomal dominant cancer syndrome characterized by:

• colonic polyposis
• osteomas (maxilla, mandible, skull)
• scoliosis
• epidermoid cysts
• soft-tissue tumors (fibromas, desmoid tumors, lipomas)

Adenocarcinoma of the colon develops in 60% of patients by the age of 40 years.

Torre's syndrome is an autosomal dominant cancer syndrome characterized by:

• one or more sebaceous tumors (adenoma, epithelioma, carcinoma)
• one or more internal neoplasms, usually colorectal or genitourinary, rarely lymphoma

Cowden's syndrome is an autosomal dominant cancer syndrome characterized by:

• multiple tricholemmomas (which resemble warts) around the mouth, nose, and ears
• breast cancer and thyroid cancer
• fibrocystic disease of the breast
• thyroid adenoma

Hirsutism, the presence of coarse, male-type hair in a woman, may indicate androgen excess, eg, an adrenal or ovarian tumor. By contrast, hypertrichosis, or excessive growth of vellus hairs in any hair-bearing area, may occur with malignancy, metabolic disorders, or medications, such as cyclosporine and minoxidil.

• Treatment: appropriate treatment of the underlying disorder

Sweet's syndrome (Figure 15), or acute febrile neutrophilic dermatosis, has a strong association with acute myelocytic or myelomonocytic leukemia.⁴ Affected patients have painful, reddened plaques on the face, extremities, and trunk. Associated systemic symptoms include fever, arthralgias, myalgias and conjunctivitis.

• Differential diagnosis: erythema multiforme, deep fungal infection, pyoderma gangrenosum, cutaneous metastases
• Treatment: systemic corticosteroids, dapsone

Multiple mucosal neuromas syndrome is associated with multiple endocrine neoplasia II (MEN II)—medullary thyroid carcinoma, pheochromocytoma, and parathyroid adenoma. Affected patients have numerous fibromas on the skin and mucosa.

Dermatomyositis, an inflammatory connective tissue disease, is characterized by symmetric proximal muscle weakness (myositis); photosensitivity; papules and plaques on the hands, elbows, and knees (Gottron's papules) (Figure 16); and periorbital edema with a violaceous hue (heliotrope). Other features include scaly, telangiectatic plaques with atrophy and hypopigmentation (poikiloderma) on the face, neck, trunk, and extremities; malar erythema; and nail abnormalities (periungual telangiectases and cuticular hypertrophy). Definitive diagnosis requires a muscle biopsy, electromyogram, and measurement of muscle enzymes (aldolase, creatine kinase, transaminases). In adults dermatomyositis has a strong association with neoplasm, usually an adenocarcinoma of the breast, gastrointestinal tract, or lung.

• Differential diagnosis: systemic lupus erythematosus, photosensitive drug eruption
• Treatment: systemic corticosteroids, methotrexate

Amyloidosis of the skin may be a sign of multiple myeloma. Affected patients have purpura and ecchymoses, which develop after pressure or rubbing, and, less often, waxy papules periorbitally and on the midface, macroglossia, "pinch-purpura" (Figure 17) after trauma, and alopecia.

• Differential diagnosis: nodular amyloidosis
• Treatment: difficult; no effective therapy exists

Blistering Disease:

(see the preceding section with the same title)

Paraneoplastic pemphigus (Figure 18), characterized by intractable stomatitis and blisters on the trunk and extremities, exhibits features of pemphigus and erythema multiforme. Biopsy reveals deposition of IgG both intercellularly and at the dermal-epidermal junction by immunofluorescence. Paraneoplastic pemphigus has a strong association with non-Hodgkin's lymphoma and chronic lymphocytic leukemia and may also occur with thymoma, either with or without myasthenia gravis, and Castleman's disease.

• Differential diagnosis: pemphigus vulgaris, bullous pemphigoid, erythema multiforme
• Treatment: varies based on underlying disease

Erythema gyratum repens is a rare but very distinctive skin disease characterized by reddened concentric bands in a whorled or wood grain pattern. It has a strong association with lung cancer, as well as breast, cervical, and gastrointestinal cancers.⁵

• Treatment: appropriate treatment of the underlying malignancy

Pseudoxanthoma elasticum (PXE) (Figure 20) is an inherited or acquired (autosomal recessive) disease characterized by yellow papules over redundant skin folds on the neck, abdomen, and groin. PXE represents a defect in elastic fibers, which become brittle and calcified. Skin biopsy reveals swollen, fragmented elastic fibers. Funduscopic examination reveals angioid streaks. PXE may include hypertension, peripheral vascular and coronary artery disease, retinal and gastrointestinal hemorrhage, and strokes.

• Differential diagnosis: cutis laxa, Ehlers-Danlos syndrome
• Treatment: no definitive treatment is available

Ehlers-Danlos syndrome (EDS) is characterized by hyperextensibility, hypermobility, skin fragility, and "fish-mouth" scars, representing an abnormality in collagen biosynthesis. At least eleven types of EDS exist with varying associated features including mitral valve prolapse, blue sclerae, aneurysm, aortic dissection, hernias, angina, gastrointestinal bleeding (perforation), and peripheral vascular disease, depending on the type and severity of disease.

• Differential diagnosis: cutis laxa
• Treatment: protection of the skin and treatment of systemic findings

Sarcoidosis is a multisystem, granulomatous disease of the lungs, bones, eyes, and skin. Skin disease, affecting 15 - 30% of patients, includes red to purple plaques of the nose (lupus pernio) (Figure 21); midfacial papules; annular plaques; and plaques or nodules on the trunk and extremities. Erythema nodosum, the most common cutaneous manifestation of sarcoidosis, is an acute, painful panniculitis that usually affects the shins.

• Differential diagnosis: trichoepitheliomas, rosacea, granuloma annulare
• Treatment: systemic corticosteroids, antimalarials

Psoriatic arthritis is commonly characterized by asymmetric fusiform swelling of the distal interphalangeal joints. Active disease may resemble rheumatoid arthritis. Five types of psoriatic arthritis exist; the most common is oligoarthritis of the joints of the hand, characterized by "sausage" fingers and toes. Other presentations include: symmetric polyarticular arthritis, distal interphalangeal joint disease, arthritis mutilans, and ankylosing spondylitis.

• Differential diagnosis: rheumatoid arthritis
• Treatment: nonsteroidal anti-inflammatory drugs, antimalarials, methotrexate

Lupus erythematosus is an autoimmune photosensitive dermatosis, which can be localized or systemic in nature. Discoid lupus erythematosus (DLE) (Figure 22), usually localized to the head or neck, is characterized by scarring plaques that favor the scalp, nose, cheeks, and ears. A positive antinuclear antibody may identify the approximately 5% of patients who develop systemic disease. Subacute cutaneous lupus erythematosus (SCLE) (Figure 23) is characterized by annular plaques in a sun-exposed, shawl-like distribution on the chest, back, and arms. Serology is often positive—antinuclear antibody and antibodies to Ro/SSA antigen. The cutaneous manifestations of systemic lupus erythematosus (SLE) include: malar erythema, photosensitivity, oral ulcers, discoid plaques, bullae, purpura, calcinosis cutis, and alopecia. The butterfly "rash" (malar erythema) is the most common cutaneous finding (Figure 24).

• Differential diagnosis: dermatomyositis, photosensitive drug eruption, sarcoidosis, pellagra
• Treatment: intralesional, topical, and systemic corticosteroids; other immunosuppressants; antimalarials

Scleroderma is an autoimmune skin disease which can be localized or extensive. In the localized form, known as morphea, erythematous patches evolve into dusky, hypopigmented, indurated plaques with violaceous borders, usually on the trunk. In the extensive or generalized form, known as progressive systemic sclerosis, Raynaud's phenomenon, digital sclerosis, contractures of the digits, calcinosis, and digital ulcers may occur. The extent of skin disease in generalized scleroderma correlates with the overall prognosis.

• Differential diagnosis: scleredema, scleromyxedema
• Treatment: treatment is difficult and should be based on symptoms

Reiter's syndrome (Figure 25) is the triad of urethritis, conjunctivitis, and oligoarthritis. Affected patients, usually young men, often have vesicles and crusted plaques on the penis (circinate balanitis), and erythematous pustules and papules on the palms and soles (keratoderma blennorrhagicum) that may mimic pustular psoriasis. More than 50% of patients have sacroiliitis, correlating with the presence of HLA-B27 antigen.

• Differential diagnosis: psoriasis, juvenile plantar dermatoses
• Treatment: topical cortico steroids for cutaneous disease

Erythema chronicum migrans (ECM), the hallmark of Lyme disease, is the most sensitive indicator of early infection with the tick-borne spirochete Borrelia burgdorferi. ECM develops as a red macule or papule at the site of the tick bite and gradually enlarges as an annular, reddened plaque (Figure 26) that surrounds the bite. Affected patients may have fever, arthralgia, and myalgia, and, occasionally, Bell's palsy. Late sequelae include meningoencephalitis, myocarditis, and peripheral neuropathy. Primary endemic areas in the United States are New England, the upper midwest, and Pacific northwest.

• Differential diagnosis: cellulitis, spider bite, erythema multiforme, erythema annulare centrifugum
• Treatment: doxycycline

Most patients with dermatitis herpetiformis have a gluten-sensitive enteropathy (see preceding section on this topic).

Hepatitis C infection may be associated with various skin diseases, namely leukocytoclastic vasculitis, cutaneous B-cell lymphoma, cryoglobulinemia, pruritus, porphyria cutanea tarda, urticaria, prurigo nodularis, and lichen planus.

Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) is an autosomal dominant disorder characterized by numerous telangiectases on the skin and oral mucosa (Figure 27). Recurrent epistaxis is the most common presenting manifestation of the syndrome. Similar telangiectases may involve the lungs, liver, brain, eye, and gastrointestinal tract; hemorrhage may occur at any site. Pulmonary arteriovenous fistulas and CNS angioma may also occur.

• Differential diagnosis: generalized essential telangiectasia
• Treatment: cauterization and iron supplementation in severe cases

Peutz-Jeghers syndrome is an autosomal dominant disease characterized by lentigines on the skin and mucosa (lips, buccal mucosa, periorbital region, dorsal surfaces of the fingers and toes), and polyps of the small intestine. The polyps are usually benign hamartomas with low malignant potential.

• Differential diagnosis: LEOPARD, NAME, and LAMB syndromes
• Treatment: based on systemic symptoms

Pyoderma gangrenosum (PG) is a neutrophilic dermatosis, characterized by painful ulcers with boggy, undermined edges and a border of gray or purple pigmentation (Figure 28). The ulcers usually occur on the legs ⁶ and often follow trauma (pathergy). About 50% of affected patients have an underlying disorder, usually inflammatory bowel disease, rheumatoid arthritis, or a paraproteinemia, usually an IgA gammopathy.

• Differential diagnosis: infection, vasculitis, and factitious disorder
• Treatment: systemic corticosteroids, intralesional and topical cortico steroids, cyclosporine, other immunosuppressants

Approximately 30 - 50% of diabetic patients have or will have skin disease. Table 1 outlines the most common cutaneous manifestations of diabetes (arranged by frequency of occurrence—more to less frequent).

Porphyrias are inherited or acquired blistering disorders of heme biosynthesis. Each type, erythropoietic, hepatic, or mixed, is associated with a specific enzyme defect in the heme pathway. Porphyria cutanea tarda (PCT), the most common porphyria, is a hepatic porphyria with acquired and sporadic forms (Figure 29), characterized by a deficiency in uroporphyrinogen decarboxylase, leading to the accumulation of porphyrin by-products in the urine and serum. Precipitating factors include alcohol ingestion, estrogen administration, certain hepatotoxins (dinitrochlorobenzene, carbon tetrachloride), dialysis, and hepatitis B or C infection. PCT includes photosensitivity, skin fragility, bullae and erosions on sun-exposed skin (especially the dorsal hands), and hypertrichosis.

• Differential diagnosis: bullous systemic lupus erythematosus, epidermolysis bullosa acquisita, pseudoporphyria, variegate porphyria
• Treatment: phlebotomy, antimalarials

Pseudoporphyria mimics PCT without an enzyme defect; plasma and urinary porphyrins are normal. Medications (nonsteroidal anti-inflammatory drugs, furosemide, nalidixic acid, and tetracycline) are the most common cause of pseudoporphyria; less common causes are tanning bed use and hemodialysis.

• Differential diagnosis: same as PCT
• Treatment: removal of cause

1. Kahn LE, Russo G, Millikan LE. Genetic and acquired cutaneous disorders associated with internal malignancy. Int. J Dermatol. 1995;34:749-758.
   
   
2. Grattan C, Powell S, Humphreys F. Management and diagnostic guidelines for urticaria and angio-oedema. Br J Dermatol. 2001;144:708-14.
   
   
3. Scott JE, Ahmed AR. The blistering diseases. Med Clin North Am. 1998;82:1239-1283.
   
   
4. Von den Driesch P. Sweet's syndrome (acute febrile neutrophilic dermatosis). J Am Acad Dermatol. 1994;31:535.
   
   
5. Poole S, Fenske NA. Cutaneous markers of internal malignancy. I, II. J Am Acad Dermatol. 1993;28:1,147.
   
   
6. Callen JP. Pyoderma gangrenosum. Lancet. 1998;351:581-585.
   
   
7. Perez MI, Kohn SR. Cutaneous manifestations of diabetes mellitus. J Am Acad Dermatol. 1994;30:519.

This information is provided for general medical education purposes only and is not meant to substitute for the independent medical judgment of a physician relative to diagnostic and treatment options of a specific patient's medical condition.

In no event will The Cleveland Clinic Foundation be liable for any decision made or action taken in reliance upon the information provided through this web site.