Herpes simplex
Herpes simplex: Excerpt from Professional Guide to Diseases (Eighth Edition)
Herpes simplex, a recurrent viral infection, is caused by Herpesvirus hominis (HVH), a widespread infectious agent. Herpes type I, which is transmitted by oral and respiratory secretions, affects the skin and mucous membranes, commonly producing cold sores and fever blisters. Herpes type II primarily affects the genital area and is transmitted by sexual contact. However, cross-infection may result from orogenital sex or autoinoculation from one site to another.
Causes and incidence
About 85% of all HVH infections are subclinical; the others produce localized lesions and systemic reactions. After the first infection, a patient is a carrier susceptible to recurrent infections, which may be provoked by fever, menses, stress, heat, and cold. However, the patient usually has no constitutional signs and symptoms in recurrent infections.
Primary HVH is the leading cause of childhood gingivostomatitis in children ages 1 to 3. It causes the most common form of nonepidemic encephalitis and is the second most common viral infection in pregnant women. It can pass to the fetus transplacentally and, in early pregnancy, may cause spontaneous abortion or premature birth.
Herpes infection is equally common in males and females. Worldwide in distribution, it's most prevalent among children in lower socioeconomic groups who live in crowded environments. Saliva, stool, skin lesions, purulent eye exudate, and urine are potential sources of infection.
Signs and symptoms
In neonates, HVH symptoms usually appear 1 to 2 weeks after birth. They range from localized skin lesions to a disseminated infection of organs, such as the liver, lungs, or brain. Common complications include seizures, mental retardation, blindness, chorioretinitis, deafness, microcephaly, diabetes insipidus, and spasticity. Up to 90% of infants with disseminated disease die.
Primary infection in childhood may be localized or generalized and occurs after an incubation period of 2 to 12 days. After brief prodromal tingling and itching, localized infection causes typical primary lesions. These erupt as vesicles on an erythematous base, eventually rupture and leave a painful ulcer, followed by a yellowish crust. Vesicles may form on any part of the oral mucosa, especially the tongue, gingiva, and cheeks. Healing begins 7 to 10 days after onset and is complete in 3 weeks.
Generalized infection begins with fever, pharyngitis, erythema, and edema. Vesicles occur with submaxillary lymphadenopathy, increased salivation, halitosis, anorexia, and a fever of up to 105° F (40.6° C). Herpetic stomatitis may lead to severe dehydration in children. A generalized infection usually runs its course in 4 to 10 days. In this form, virus reactivation causes cold sores — a single or group of vesicles in and around the mouth.
Genital herpes usually affects adolescents and young adults. Typically painful, the initial attack produces fluid-filled vesicles that ulcerate and heal in 1 to 3 weeks. Fever, regional lymphadenopathy, and dysuria may also occur.
Usually, herpetic keratoconjunctivitis is unilateral and causes only local signs and symptoms: conjunctivitis, regional adenopathy, blepharitis, and vesicles on the lid. Other ocular effects may include excessive lacrimation, edema, chemosis, photophobia, and purulent exudate.
Both types of HVH can cause acute sporadic encephalitis with altered level of consciousness, personality changes, and seizures. Other effects may include smell and taste hallucinations and neurologic abnormalities such as aphasia.
Herpetic whitlow, an HVH finger infection, affects many nurses. First the finger tingles and then it becomes red, swollen, and painful. Vesicles with a red halo erupt and may ulcerate or coalesce. Other effects may include satellite vesicles, fever, chills, malaise, and a red streak up the arm.
Diagnosis
CONFIRMING DIAGNOSIS Typical lesions may suggest HVH infection. However, confirmation requires isolation of the virus from local lesions and histologic biopsy.
A rise in antibodies and moderate leukocytosis may support the diagnosis.
Treatment
No cure for herpes exists; however, recurrences tend to be milder and of shorter duration than the primary infection. Symptomatic and supportive therapy is essential. Generalized primary infection usually requires an analgesic-antipyretic to reduce fever and relieve pain. Anesthetic mouthwashes, such as viscous lidocaine, may reduce the pain of gingivostomatitis, enabling the patient to eat and preventing dehydration. (Avoid alcohol-based mouthwashes.) Drying agents, such as calamine lotion, ease the pain of labial or skin lesions. Avoid petroleum-based ointments, which promote viral spread and slow healing.
Refer patients with eye infections to an ophthalmologist. Topical corticosteroids are contraindicated in active infection, but idoxuridine, trifluridine, and vidarabine are effective.
Oral acyclovir may bring relief to patients with genital herpes. Frequent prophylactic use of acyclovir in immunosuppressed transplant patients prevents disseminated disease.Foscarnet can be used to treat HVH that’s resistant to acyclovir. Anti-viral agents similar to acyclovir are valacyclovir and famciclovir. These agents are more active than acyclovir.
Special considerations
❑Teach the patient with genital herpes to use warm compresses or take sitz baths several times per day; to use a drying agent, such as povidone-iodine solution; to increase fluid intake; and to avoid all sexual contact during the active stage.
❑For pregnant women with active HVH infection at the time of delivery, a cesarean delivery is recommended to decrease the risk of infecting the neonate.
❑Health care personnel should use standard precautions, such as gloves, for contact with mucous membranes to prevent acquisition of herpetic whitlow.
❑Instruct patients with herpetic whitlow not to share towels or eating utensils. Educate staff members and other susceptible people about the risk of contagion. Abstain from direct patient care if you have herpetic whitlow.
❑Tell patients with cold sores not to kiss infants or people with eczema. (Those with genital herpes pose no risk to infants if their hygiene is meticulous.)
❑Patients with central nervous system infection alone need no isolation.
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
More About Cold sores
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Medical Books Excerpts
- Common cold
- "Professional Guide to Diseases (Eighth Edition)" (2005)
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- Mouth lesions
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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