Herpes simplex virus infection
1. Impetigo is a bacterial infection of the skin which occurs in two forms: bullous and nonbullous, the former caused by S. aureus, the latter by either S. aureus, Group A streptococcus, or both. Three-fourths of all cases of impetigo are of the nonbullous type and usually are seen in children, although it may be seen in adults as well. The most common areas of involvement are the face, primarily the paranasal area, and extremities, often after trauma to these areas. Discomfort and pruritus at the site are common. Initially the patient may present with a small pustule or vesicle at the site which rapidly progresses to a honey-crusted plaque with surrounding erythema. If the lesion(s) is left untreated, regional lymphadenopathy may occur but the patient does not exhibit constitutional symptoms. Untreated lesions may resolve spontaneously or ulcerate. Bullous impetigo presents as multiple vesicles and/or bullae on essentially normal skin with clear to yellow fluid content that becomes turbid with time. There is no associated erythema in these sharply demarcated superficial lesions. Many will coalesce and subsequently rupture, leaving thin crusts. Gram's stain shows gram-positive cocci in clusters; culture is positive for S. aureus. Treatment can be managed locally with topical mupirocin ointment, normal hygiene, and removal of crusts. Left untreated, complications of lymphangitis, cellulitis, and bacteremia can occur.
2. Contact dermatitis is an inflammatory response of the skin, either to an irritant or antigen. Common antigens causing contact dermatitis are nickel, potassium dichromate, formaldehyde, and paraphenylenediamine. Strong alkalis and acids, such as sodium and potassium hydroxides, are common irritants. Allergic contact dermititis due to plants (poison ivy, poison oak) results from direct injury to the skin, with lesions often seen distributed in a linear fashion. Symptoms of discomfort and pruritus occur soon after exposure. Although allergic contact dermatitis usually involves skin at the site of primary exposure, it can also spread to other sites either through contact or via autosensitization. Lesions may present as erythematous macules, papules, vesicles, or even bullae depending on the degree of involvement in the acute setting. Later, with chronic involvement, skin becomes fissured or lichenified with or without papulovesicles. Most cases of contact dermatitis are seen in adults but can occur in all ages. Elderly patients are most often more severely affected, as are infants and very young children. Treatment consists of removing the offending agent, Burrow's soaks, antipruritics, emollients, and topical corticosteroids. Patch testing may be helpful in identifying specific allergens. Secondary bacterial infections are treated with systemic antibiotics.
3. Herpes simplex virus infection can be caused by herpes simplex virus type 1 (HSV-1) or herpes simplex virus type 2 (HSV-2). Both HSV-1 and HSV-2 can cause primary and recurrent infections with mucocutaneous involvement being severe or mild. Initial or primary infection is usually quite severe, followed by a period of dormancy in neuronal cells located in ganglia. Recurrent disease occurs once the dormant virus is reactivated along the nerve fiber, resulting in skin infection. Primary infection of both HSV-1 and HSV-2 occurs via direct exposure through mucocutaneous contact with another infected person. This can occur via oral or sexual contact with an infected partner or exposure to a mother's infectious vaginal secretions during delivery of a neonate. In primary facial-oral herpes infection, patients present with acute gingivostomatitis and ulcerations of the oral and buccal mucosa. Most of these cases occur in childhood (ages 1-5 years) and often go undetected. The usual clinical picture includes fever; sore throat; painful, often coalescing vesicles; and ulcerations or erosions on the tongue, palate, gingival, and buccal mucosa. There is often halitosis, drooling, and local lymphadenopathy, in addition to general malaise. Diagnosis is established via viral cultures or by blood analysis for antigens and monoclonal antibodies. Recurrent infections are much less severe. Recurrent lesions present as grouped vesicles on an erythematous base which eventually become crusted ("honey colored crusts"). Incidence average three to four outbreaks annually and is often triggered by sun exposure, stress, and fatigue. Unlike aphthous ulcers which begin on wide, separated areas of the buccal mucosa, herpes lesions start as a few grouped lesions on one part of the buccal mucosa.
4. Varicella is the correct answer. Also known as chicken pox, varicella is a highly contagious viral infection caused by the varicella-zoster virus. Until the recent advent of the varicella vaccine in 1995, varicella appeared in epidemics, affecting most urban children before puberty. Although generally mild and self-limiting, it can occasionally cause complications that can be life-threatening in certain populations (young, unvaccinated infants and children, immunocompromised adults, for example). Varicella pneumonia and encephalitis are both associated with a high mortality rate. Household transmission rates are 80% to 90%, with peak incidence of transmission occurring in March, April, and May in temperate climates. Second cases within households are usually the more severe. Length and extent of eruption, systemic symptoms, and complications are more extensive in adults, especially those taking immunosuppressive drugs, particularly oral and systemic corticosteroids. The incubation period is 10 to 21 days, but is usually between 14 to 15 days. Transmission occurs via direct contact with cutaneous lesions and by respiratory droplets. Crowded living conditions at home, schools, and daycare centers are the primary areas of exposure. Patients are virulent for at least 4 days before and 5 days after the appearance of the rash. Constitutional symptoms, including fever, sore throat, cough, coryza, headache, malaise, and pruritus are usually mild. The exanthem appears in crops with between 200 to 500 lesions present. This highly characteristic rash begins with red macules which continue through stages of papule, vesicle, pustule, and crust. This simultaneous presence of different stages of rash is pathopneumonic for varicella. Vesicles develop rapidly (within 24 hours) from macules and their appearance on an erythematous base is often described as "dewdrop on a rose petal" (see Figures 1-4). New crops continue to appear for several days primarily on the trunk, face, and oral mucosa. Most lesions crust by 6 days and heal completely by 14 to 16 days. Lesions can become secondarily infected (usually by S. aureus), identified by redness and swelling circumferencely and at the base. These can lead to classic, round, crater-like depressed scars of chicken pox ("pockmark"). In addition to bacterial skin infection, complications include varicella pneumonia (rare in normal children but the most common complication of adult chicken pox), hepatitis (seen primarily in immunosupressed patients), and central nervous system involvement, such as encephalitis and Reye's syndrome. An active case of varicella produces lifelong immunity. Once it has produced chicken pox, the varicella-zoster virus becomes dormant in the ganglia. Treatment is supportive and may include oral acyclovir therapy, given in the first 24 hours of the disease for otherwise healthy children and adults. Immunocompromised patients and those with complications (pneumonia, hepatitis) will require additional treatment. Chickenpox during pregnancy is a significant risk for mother and child in all three trimesters, although risk is greatest during the first 20 weeks of pregnancy. There is a high risk of disseminated varicella in the newborn infant if the mother's rash appears 1 to 4 days before delivery or if the infant's rash appears 5 to 10 days postpartum. Since the newborn is susceptible to disseminated disease due to an immature immune system, protection is provided to the infant by administering zoster immune globulin (ZIG), varicella-zoster immune globulin (VZIG), or gamma globulin if the prior two are unavailable.
5. Enteroviral infection is any number of single-stranded ribonucleic acid (RNA) viruses commonly seen in infants and young children. Poliovirus, coxsackievirus, and echovirus are all enteroviruses. Symptoms range from mild to severe. The clinical syndromes associated with enteroviral infections include herpangina, hand-foot-and-mouth disease, myocarditis, and pleurodynia. Patients with herpangina present with erythematous macules, usually on the posterior pharynx or palate, which progress to vesicles that eventually ulcerate. Patients with hand-foot-and-mouth disease will also present with similar vesicles on the posterior pharynx, yet they are much less painful than with herpangina. In addition, vesicles will appear on the palms, soles, and interdigital web spaces and do not crust over. Diagnosis of any of the enteroviruses is often made based on clinical findings, age groups, geographical location, and seasonal outbreaks.
Dermatology Nursing. 2008;20(1):47-49,53. © 2008 Jannetti Publications, Inc.
Cite this: What's Your Assessment? - Medscape - Feb 01, 2008.