Professional Guide to Signs and Symptoms
5th Edition

Erythema [Erythroderma]
Dilated or congested blood vessels produce red skin, or erythema, the most common sign of skin inflammation or irritation. Erythema may be localized or generalized and may occur suddenly or gradually. Skin color can range from bright red in patients with acute conditions to pale violet or brown in those whose conditions are chronic. Erythema must be differentiated from purpura, which causes redness from bleeding into the skin. When pressure is applied directly to the skin, erythema blanches momentarily, but purpura doesn’t.
Erythema usually results from changes in the arteries, veins, and small vessels that lead to increased small-vessel perfusion. Drugs and neurogenic mechanisms can allow extra blood to enter the small vessels. Erythema can also result from trauma and tissue damage; changes in supporting tissues, which increase vessel visibility; and a number of rare disorders. (See Rare causes of erythema.)
HISTORY AND PHYSICAL EXAMINATION
If erythema isn’t associated with anaphylaxis, obtain a detailed health history. (See Differential diagnosis: Erythema, pages 310 and 311.) Find out how long the patient has had the erythema and where it first began. Has he had any associated pain or itching? Has he recently had a fever, an upper respiratory tract infection, or joint pain? Does he have a history of skin disease or other illness? Does he or anyone in his family have allergies, asthma, or eczema? Find out if he has been exposed to someone who has had a similar rash or who is now ill. Did he have a recent fall or injury in the erythematous area?
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Obtain a complete drug history, including recent immunizations. Ask about food intake and exposure to chemicals.
Begin the physical examination by assessing the extent, distribution, and intensity of erythema. Look for edema and other skin lesions, such as urticaria, scales, papules, and purpura. Examine the affected area for warmth, and gently palpate it to check for tenderness or crepitus.
MEDICAL CAUSES
  • Allergic reactions. Foods, drugs, chemicals, and other allergens can cause an allergic reaction and erythema. A localized
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    allergic reaction also produces hivelike eruptions and edema.
    Anaphylaxis, a life-threatening reaction, produces relatively sudden erythema in the form of urticaria. It also produces flushing; facial edema; diaphoresis; weakness; sneezing; bronchospasm with dyspnea and tachypnea; shock with hypotension and cool, clammy skin; and possibly airway edema with hoarseness and stridor.
  • Burns. In thermal burns, erythema and swelling appear first, possibly followed by deep or superficial blisters and other signs of damage that vary with the severity of the burn. Burns from ultraviolet rays, such as sunburn, cause delayed erythema and tenderness on exposed areas of the skin.
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  • Candidiasis. When this fungal infection affects the skin, it produces erythema and a scaly, papular rash under the breasts and at the axillae, neck, umbilicus, and groin (intertrigo). Small pustules commonly occur at the periphery of the rash (satellite pustulosis).
  • Cellulitis. This bacterial infection of the skin and subcutaneous tissue causes erythema, tenderness, and edema.
  • Dermatitis. Erythema commonly occurs in this family of inflammatory disorders. In atopic dermatitis, erythema and intense pruritus precede the development of small papules that may redden, weep, scale, and lichenify. These occur most commonly at skin folds of the extremities, neck, and eyelids.
    Contact dermatitis occurs after exposure to an irritant. It quickly produces erythema and vesicles, blisters, or ulcerations on exposed skin.
    In seborrheic dermatitis, erythema appears with dull red or yellow lesions. Sharply marginated, these lesions are sometimes ring shaped and covered with greasy scales. They usually occur on the scalp, eyebrows, ears, and nasolabial folds, but they may form a butterfly rash on the face or move to the chest or to skin folds on the trunk. This disorder is common in patients infected with the human immunodeficiency virus and in infants (cradle cap).
  • Dermatomyositis. This disorder, most common in women older than age 50, produces a dusky lilac rash on the face, neck, upper torso, and nail beds. Gottron’s papules (violet, flat-topped lesions) may appear on finger joints.
  • Erysipelas. This skin infection caused by group A beta-hemolytic streptococci is characterized by an abrupt onset of reddish, well-demarcated, tender, warm, sometimes elevated lesions, mainly on the face and neck but sometimes also on the extremities. Flaccid, pus-filled bullae may develop after 2 to 3 days. Extension into deeper tissues is rare. Other signs and symptoms include fever, chills, cervical lymphadenopathy, vomiting, headache, sore throat, warmth and tenderness in the affected area and, possibly, alopecia.
  • Erythema annulare centrifugum. Small, pink infiltrated papules appear on the trunk, buttocks, and inner thighs, slowly spreading at the margins and clearing in the center. Itching, scaling, and tissue hardening may occur.
  • Erythema marginatum rheumaticum. Associated with rheumatic fever, this disorder causes erythematous lesions that are superficial, flat, and slightly hardened. They shift, spread rapidly, and may last for hours or days, recurring after a time.
  • Erythema multiforme. This acute inflammatory skin disease develops as a result of drug sensitivity after an infection (most commonly herpes simplex or a mycoplasmal infection), allergies, or pregnancy. One-half of the cases are of idiopathic origin.
    Erythema multiforme minor produces reddish pink iris-shaped, urticarial, localized lesions with little or no mucous membrane involvement. Most lesions occur on flexor surfaces of the extremities. Burning or itching may occur before or in conjunction with lesion development. Lesions appear in crops and last 2 to 3 weeks. After 1 week, they become flat or hyperpigmented. Early signs and symptoms may include a mild fever, cough, and sore throat.
    Erythema multiforme major usually occurs as a drug reaction; causes widespread symmetrical, bullous lesions that may become confluent; and includes erosions of the mucous membranes. Erythema is characteristically preceded by blisters on the lips, tongue, and buccal mucosa and a sore throat. Additional early signs and symptoms include cough, vomiting, diarrhea, coryza, and epistaxis. Later signs and symptoms include fever, prostration, difficulty with oral intake because of mouth and lip lesions, conjunctivitis due to ulceration, vulvitis, and balanitis. The most severe form of this disorder is known as Stevens-Johnson syndrome, a multisystem disorder that can occasionally be fatal. In addition to all signs and symptoms mentioned above, patients develop
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    exfoliation of the skin from disruptions of bullae, although less than 10% of the body surface area is affected. These areas resemble second-degree thermal burns and should be cared for as such. Fever may rise to 102° F to 104° F (38.9° C to 40° C). The patient may also experience tachypnea; a weak, rapid pulse; chest pain; malaise; and muscle or joint pain.
  • Erythema nodosum. Sudden bilateral eruption of tender erythematous nodules characterizes this disorder. These firm, round, protruding lesions usually appear in crops on the shins, knees, and ankles but may occur on the buttocks, arms, calves, and trunk as well. Other effects include mild fever, chills, malaise, muscle and joint pain and, possibly, swollen feet and ankles. Erythema nodosum is associated with various diseases, most notably inflammatory bowel disease, sarcoidosis, tuberculosis, and streptococcal and fungal infections.
  • Frostbite. First-degree frostbite turns the affected body part a lifeless gray color, followed by an intense bluish red flush on rewarming. Blisters, lack of feeling, and tissue necrosis may follow.
  • Gout. This disease, which generally affects men ages 40 to 60, is characterized by tight and erythematous skin over an inflamed, edematous joint.
  • Intertrigo. In this superficial fungal infection, skin friction usually causes symmetrical erythema that may be accompanied by soreness and itching. Typically, erythema occurs in skin folds, such as in the groin; in severe cases, the skin may become bright red with erosion and maceration.
  • Kawasaki syndrome. This acute illness of unknown cause, which primarily affects children younger than age 5, commonly produces a rash or erythema. No test is available for Kawasaki syndrome, which can cause serious heart damage and death if not detected and treated immediately. Additional characteristic signs include fever, conjunctival injection, and lymphadenopathy. Patients are treated with I.V. gamma globulin.
  • Liver disease (chronic). Any chronic liver disease, such as cirrhosis, can cause local vasodilation and palmar erythema along with jaundice, pruritus, spider angiomas, xanthomas, and characteristic systemic signs.
  • Lupus erythematosus. Both discoid and systemic lupus erythematosus (SLE) can produce a characteristic butterfly rash. This erythematous eruption may range from a blush with swelling to a scaly, sharply demarcated, macular rash with plaques that may spread to the forehead, chin, ears, chest, and other sun-exposed parts of the body.
    In discoid lupus erythematosus, other signs and symptoms may include telangiectasia, hyperpigmentation, ear and nose deformity, and mouth, tongue, and eyelid lesions.
    In SLE, acute onset of erythema may be accompanied by photosensitivity and mucous membrane ulcers, especially in the nose and mouth. Mottled erythema may occur on the hands, with edema around the nails and macular reddish purple lesions on the fingers. Telangiectasia occurs at the base of the nails or eyelids along with purpura, petechiae, ecchymoses, and urticaria. Other findings vary according to the body systems affected but typically include low-grade fever, malaise, weakness, headache, arthralgia, arthritis, depression, lymphadenopathy, fatigue, anorexia, weight loss, nausea, vomiting, diarrhea, and constipation.
  • Necrotizing fasciitis. This streptococcal infection usually begins with an area of mild erythema at the site of insult, which soon changes from red to purple and then blue. The appearance of fluid-filled blisters and bullae indicates the rapid progression of the necrotizing process. By days 7 to 10, dead skin begins to separate at the margins of the erythema, revealing extensive necrosis of the subcutaneous tissue. Other findings include fever, hypovolemia and, in later stages, hypotension and respiratory insufficiency—signs of overwhelming sepsis that require supportive care.
  • Polymorphous light eruption. This condition produces erythema, vesicles,
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    plaques, and multiple small papules on sun-exposed areas, which may later eczematize, lichenify, and excoriate. Pruritus may also occur.
  • Psoriasis. Silvery white scales over a thickened erythematous base usually affect the elbows, knees, chest, scalp, and intergluteal folds. The fingernails may become thick and pitted.
  • Raynaud’s disease. In this disorder, the skin on the hands and feet typically blanches and cools after exposure to cold and stress and later becomes warm and purplish red.
  • Rheumatoid arthritis. In a flare-up of this disorder, erythema occurs over the affected joints along with heat, swelling, pain, and stiffness. Earlier symptoms include malaise, fatigue, myalgia, prolonged morning stiffness, and clumsiness. As the disease progresses, muscle atrophy, palmar erythema, generalized edema, mottled skin, and structural deformities occur.
  • Rosacea. Scattered erythema initially develops across the center of the face, followed by superficial telangiectases, papules, pustules, and nodules. Rhinophyma may occur on the lower half of the nose.
  • Rubella. Typically, flat solitary lesions join to form a blotchy pink erythematous rash that spreads rapidly to the trunk and extremities in this disorder. Occasionally, small red lesions (Forschheimer spots) occur on the soft palate. Lesions clear in 4 to 5 days. The rash usually follows a fever (up to 102° F [38.9° C]), headache, malaise, sore throat, a gritty eye sensation, lymphadenopathy, pain in the joints, and coryza.
  • Staphylococcal scalded skin syndrome. This endotoxin-mediated epidermolytic disease is caused by a clinically unapparent Staphylococcus aureus infection and primarily affects infants (Ritter’s disease) and small children. It’s characterized by erythema and widespread exfoliation of superficial epidermal layers, resembling scalded skin. Associated signs and symptoms include low-grade fever and irritability. Care must be taken to maintain hydration and prevent secondary infections of denuded areas; hospitalization is commonly required. Death may occur, especially in infants with extensive disease.
  • Thrombophlebitis. Although this disorder is sometimes asymptomatic, it can produce erythema over the inflamed vein. Fever, chills, and malaise may accompany severe localized pain, warmth, and induration; distal edema; and a positive Homans’ sign.
  • Toxic shock syndrome. This infectious disorder, which is caused by a toxin-producing S. aureus infection, causes sudden, diffuse erythema in the form of a macular rash. It’s accompanied by a sudden high fever, myalgia, vomiting, severe diarrhea, and sudden hypotension that may lead to shock. Desquamation occurs after 1 to 2 weeks, especially on the palms and soles. This syndrome usually affects young women and has been associated with the use of tampons during menses.
OTHER CAUSES
  • Radiation and other treatments. Radiation therapy may produce dull erythema and edema within 24 hours. As the erythema fades, the skin becomes light brown and mildly scaly. Any treatment that causes an allergic reaction can also cause erythema.
SPECIAL CONSIDERATIONS
Because erythema can cause fluid loss, closely monitor and replace fluids and electrolytes, especially in patients with burns or widespread erythema. Be sure to withhold all medications until the cause of the erythema has been identified. Then expect to administer an antibiotic and a topical or systemic corticosteroid.
For a patient with itching skin, expect to give soothing baths or apply open wet
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dressings containing starch, bran, or sodium bicarbonate; also administer an antihistamine and an analgesic as needed. Advise a patient with leg erythema to keep his legs elevated above heart level. For a burn patient with erythema, immerse the affected area in cold water, or apply a sheet soaked in cold water to reduce pain, edema, and erythema.
Prepare the patient for diagnostic tests, such as skin biopsy to detect cancerous lesions, cultures to identify infectious organisms, and sensitivity studies to confirm allergies.
PEDIATRIC POINTERS
Many newborns develop a pink papular rash (erythema toxicum neonatorum) that starts within the first 4 days after birth and spontaneously disappears by the 10th day. Neonates and infants can also develop erythema from infections and other disorders. For instance, candidiasis can produce thick white lesions over an erythematous base on the oral mucosa as well as diaper rash with beefy red erythema.
Roseola, rubeola, scarlet fever, granuloma annulare, and cutis marmorata also cause erythema in children.
GERIATRIC POINTERS
Many elderly patients have well-demarcated purple macules or patches, usually on the back of the hands and on the forearms. Known as actinic purpura, this condition results from blood leaking through fragile capillaries. The lesions disappear spontaneously.
PATIENT COUNSELING
Teach patients with a chronic disease, such as SLE or psoriasis, about the character of their typical rashes so they can be alert to any flare-ups of their disease. Also,
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advise such patients to avoid sun exposure and to use sunblock when appropriate.