Encyclopedia of Health and Medicine

156 The Integumentary System
ures include HAND WASHING after coughing or
sneezing.
See also SCARLET FEVER.
erythema multiforme A HYPERSENSITIVITY REAC-
TION, commonly to medications and sometimes to
viral INFECTION, in which circular, weltlike lesions
resembling targets form on the arms, hands, legs,
and feet. Lesions also often form on and around
the lips and inside the MOUTH. The center of the
LESION is typically pale and blistered, surrounded
with a reddened (erythematous) middle ring. The
outer ring often has a purplish tint, giving it a
bruiselike appearance. Lesions typically begin
erupting within three days of the causative exposure,
rising suddenly. Some people experience tingling,
itching, or a burning sensation at the site of
the lesion.
Common causes of erythema multiforme
include
• infection with the HERPES SIMPLEX VIRUS
• ANTIBIOTIC MEDICATIONS
• ANTISEIZURE MEDICATIONS
• aspirin and NONSTEROIDAL ANTI-INFLAMMATORY
DRUGS (NSAIDS)
• numerous other medications
The uniquely characteristic lesions in provide
fairly conclusive diagnosis. The causative agent
may be clear, such as a recently taken medication,
or remain unknown (idiopathic). Most erythema
multiforme outbreaks are self-limiting and clear
up two to three weeks after exposure to the
causative agent ends. Treatment to provide relief
from discomfort may include ANTIHISTAMINE MED-
ICATIONS for itching, ANALGESIC MEDICATIONS for PAIN
relief, and topical corticosteroids for INFLAMMATION.
Nearly always the lesions heal without scarring or
other complications. Prevention of future outbreaks
is difficult as there are so many potential
causes.
See also TOXIC EPIDERMAL NECROLYSIS; URTICARIA.
erythema nodosum The eruption of red nodules
along the top surfaces of the lower legs (shins).
Erythema nodosum is nearly always a symptom of
an underlying condition, often a streptococcal
INFECTION, and represents INFLAMMATION of the fatty
tissue at the foundation of the SKIN. Other symptoms
include FEVER, PAIN and swelling in the joints,
and generalized discomfort and malaise. Erythema
nodosum occurs most commonly in young adults
between the ages of 18 and 30.
The initial eruption of nodules may clear in six
to eight weeks, though outbreaks tend to recur
over months to years. Over the course of HEALING
the nodules change color from their original bright
red to bluish red and ultimately yellow, resembling
bruises, before fading completely. The doctor
diagnoses erythema nodosum primarily on the
basis of its appearance, though may run BLOOD
tests to look for evidence of AUTOIMMUNE DISORDERS
or infection that may underlie the outbreak. Treatment
targets the underlying cause and may
include ANTIBIOTIC MEDICATIONS when there is infection
or anti-inflammatory agents such as NON-
STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) to
relieve swelling, pain, and fever.
See also JOINT; NODULE; TUBERCULOSIS.
erythrasma A chronic bacterial INFECTION of the
epidermis (outer layer of the SKIN) that produces
scaly, brownish red patches that often itch. The
patches may occur anywhere on the body though
are most common in skin folds and moist areas
such as the underarm (axilla) and groin. When
CONDITIONS ASSOCIATED WITH ERYTHEMA NODOSUM
STREP THROAT rheumatic FEVER SCARLET FEVER
Hodgkin’s LYMPHOMA Hansen’s disease bacterial infection
fungal INFECTION adverse reaction to sulfonamides PREGNANCY
ADVERSE REACTION to sulfonylureas oral contraceptives HISTOPLASMOSIS
INFLAMMATORY BOWEL DISEASE (IBD) non-Hodgkin’s lymphoma SARCOIDOSIS