Author
Aimee M. Barton, MD
Assistant Professor, Department of Pediatrics
Division of Neonatology
Georgetown University Medical Center
Washington, DC
Disclosure: Aimee M. Barton, MD, has disclosed no relevant financial relationships.
Editor
Lars Grimm, MD, MHS
House Staff
Department of Internal Medicine
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewer
Robert A. Schwartz, MD
Professor and Head, Dermatology
Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health
UMDNJ-New Jersey Medical School
Newark, New Jersey
Disclosure: Robert A. Schwartz, MD, has disclosed no relevant financial relationships.
Most pediatric skin problems are infectious in nature. Although many of these conditions are benign, it is important to be able to readily identify ones that can lead to significant morbidity or mortality to promptly initiate appropriate diagnostic and therapeutic interventions. Nonbullous impetigo from an abrasion infected by group A beta-hemolytic streptococci is shown. Image courtesy of Professor David Taplin.
Impetigo is a highly contagious gram-positive bacterial infection of the superficial layers of epidermis. It may be caused by Staphylococcus aureus, most commonly in the United States, and by group A beta-hemolytic streptococci (GABHS) most often in developing countries. Impetigo may manifest as primary pyoderma of intact skin or secondary infection of preexisting skin disease or traumatized skin, and it rarely progresses to a systemic infection. Many patients are colonized in the nares or less commonly in the perineum, axillae, pharynx, and hands. Organisms pass from one individual to another by direct hand contact. Infection occurs by entrance through broken skin, usually from scratching. Commonly associated conditions include atopic dermatitis, dermatophytosis, varicella, herpes simplex, scabies, pediculosis, thermal burns, surgery, trauma, radiation therapy, or insect bites. Immunosuppression from medications, systemic diseases, intravenous drug abuse, or dialysis encourages bacterial growth. Image courtesy of Professor David Taplin.
Impetigo may be classified as bullous and nonbullous. Nonbullous impetigo occurs in 70% of cases, with minor trauma resulting in lesions within 1-2 weeks. Bullous impetigo is usually caused by exfoliative toxins of S aureus (shown), which causes a loss of cell adhesion in the superficial dermis. It is most common in neonates and infants. Once infection is present, new lesions may develop despite lack of apparent skin breakage. Impetigo accounts for 10% of skin diseases treated in pediatric clinics, with a peak incidence in summer and fall. Risk factors include hot, humid weather, participation in contact sports, crowded living conditions, and poor hygiene. Diagnosis is usually clinical. Topical or oral antibiotic therapy is the treatment of choice. In general, most lesions are asymptomatic and heal without scarring over several weeks. In 1%-5% of cases caused by streptococcus, acute poststreptococcal glomerulonephritis may develop. Image courtesy of Professor David Taplin.
Pityriasis rosea is a common benign papulosquamous disease with a number of clinical variations. It is considered a viral exanthem, but no single virus has been proven to cause the disease, and it has been linked to upper respiratory infections. Its incidence may increase in fall and spring in temperate climates. Worldwide pityriasis rosea is estimated to account for 2% of dermatologic outpatient visits. It is more common in females than in males; most patients are 10-35 years of age. It typically begins with a solitary patch that heralds the eruption (herald patch in left image) followed by a generalized rash (right image) that appears typically 1-2 weeks later and tends to resolve over next 6 weeks. Pruritus occurs in 75% of patients, but lymphadenopathy is uncommon. Oral involvement may be evident as punctate hemorrhages, ulcers, papulovesicles, bullae, or erythematous plaques. Patients who are pregnant are at increased risk for miscarriage. Infection is associated with neonatal hypotonia, hyporeactivity, and premature delivery. Both medication eruptions and syphilis can be important mimics. Treatment is entirely supportive. The only long-term complication is usually residual hypopigmentation or hyperpigmentation. Fortunately, a single outbreak tends to confer lifelong immunity. Images courtesy of the Drexel Department of Dermatology slide collection
Hand-foot-and-mouth disease is a viral syndrome with a distinct exanthem-enanthem. It is caused by infection with an enterovirus, most commonly a coxsackievirus. The distribution is worldwide with a peak incidence in summer and fall in temperate climates. It occurs most commonly in infants and children younger than 5 years of age. Males and females are equally affected, but males are more likely to be symptomatically ill. Transmission is through fecal-oral or oral-oral routes. The classic presentation is an incubation period of 4-6 days with a prodrome of fever, malaise, anorexia, abdominal pain, and sore mouth. The enanthem then develops with painful yellow ulcers that have red halos (shown). It is the most common cause of mouth sores in pediatric patients, and younger patients are likely to have more severe symptoms.
The exanthem of hand-foot-and-mouth disease typically involves the dorsal surfaces of the hands and feet. It usually begins as erythematous macules that rapidly progress to thick-walled grey vesicles with an erythematous base (shown). These may be pruritic and spread to involve the trunk, thighs, and buttocks. The rash is usually self-limited and lasts 3-6 days. Diagnosis in hand-foot-and-mouth disease is largely clinical. In most cases, supportive therapy with antipyretics alone is necessary. Secondary skin infection is the most likely complication. For patients with severe dysphagia, codeine or topical anesthetics may be needed to ensure adequate hydration given the increased febrile insensible losses.
Chickenpox is caused by varicella-zoster virus, and 90% of cases occur in children younger than 10 years of age. It is usually acquired by inhalation of airborne respiratory droplets from an infected host, but viral transmission may occur through direct contact with vesicles. There is no racial or sexual predilection. The typical presentation is an incubation period of 10-21 days followed by the development of numerous small erythematous macules which rapidly progress over 12-14 hours to papules, clear vesicles, and pustules (shown). These will develop subsequent central umbilication and a crust will form. Vesicles may appear on the mucous membranes with painful, shallow ulcers. Diagnosis can usually be made on clinical grounds. Secondary bacterial infection is the most common complication. Infection is usually self-limited in healthy children and confers lifelong immunity. Excoriation may induce scarring. Calamine lotion, oatmeal baths, or oral antihistamines are useful for pruritic symptoms. Treatment is with acyclovir for immunocompromised children and with VariZIG™ for highly susceptible individuals within 96 hours of exposure. Image on the left shows a "dewdrop on a rose petal" characteristic vesicle of chickenpox. Image on the right shows vesicular eruption on the trunk demonstrating papules, vesicles, and crusts. Reprinted with permission from Papadopoulos AJ, et al. Cutis. 2000;65:355.
Erythema infectiosum, or fifth disease, is a common childhood exanthem caused by human parvovirus B19. Worldwide epidemics occur in late winter or early spring; 60% of adults are seropositive by age 20 years. It is primarily a disease of children aged 3-15 years and has no sexual predilection. Transmission is usually by means of respiratory droplets. The typical presentation is an incubation period of 4-14 days with subtle prodrome of headache, coryza, low-grade fever, pharyngitis, and malaise. An erythematous slapped-cheek appearance then develops (left image), which fades in 2-4 days and is followed by a macular-to-morbilliform eruption that develops on the extremities (right image). This lasts for several days and then fades, although recurrence several weeks later is possible. Complications are rare in childhood, but may include aplastic crisis and acute polyarthropathy. The majority of cases are self-limited.
Measles, or rubeola, is a very contagious disease whose incidence has fortunately been greatly reduced since the introduction of vaccination. It is one of the leading causes of death worldwide among children. Complications are more likely to occur in children under the age of 5 years. The typical presentation is an incubation period of 7-14 days followed by a prodrome lasting 4-7 days that includes high fever, cough, coryza, and conjunctivitis. Following the prodrome, an enanthem develops for 2-4 days, termed Koplik spots, which appear as white spots on the buccal mucosa (left image). These last for 3-5 days and are followed by an exanthem consisting of a mildly pruritic morbilliform rash (right image). Rash may not develop in patients who are immunocompromised.
Diagnosis of measles is primarily clinical based on the morbilliform rash (shown), fever, and coryza, but laboratory evaluation is important for public health and outbreak control. Measles is reportable to the Centers for Disease Control (CDC) and the local health department. Acute complications of measles include pneumonia, otitis media, sinusitis, diarrhea, stomatitis, lymphadenitis, subclinical hepatitis, and keratitis. Late, long-term complications include subacute sclerosis panencephalitis. Treatment for measles involves supportive intravenous hydration, antibiotics for secondary bacterial infections, and vitamin A supplementation, all of which have been shown to reduce mortality. Prophylactic treatment is warranted after exposure for unvaccinated contacts.
Molluscum contagiosum is a cutaneous infection caused by a poxvirus. It is most commonly associated with steroid therapy, atopic dermatitis, immunodeficiency, or lymphoproliferative disorders. It is most common in the tropics and subtropics. There is a bimodal age distribution in childhood and then early adulthood. Transmission may be vertical or through skin-to-skin contact. The typical presentation is an incubation period of 14-50 days followed by the development of firm, smooth, umbilicated papules (shown). They are typically 2-6 mm in diameter and may be distributed in groups of anywhere from 1 to hundreds. In some cases they may become confluent plaques. Although generally self-limited, and in some cases asymptomatic, they can persist for years. Patients with AIDS are more likely to have larger and greater numbers of lesions. The most common complications are irritation, inflammation, and secondary infection. If needed, curretage is an effective treatment option.
Scarlet fever is an infection caused by toxin-producing GABHS. The peak age range is 1-10 years. It may follow streptococcal wound infections or burns, upper respiratory infections, or even food-borne outbreaks. The typical presentation is a cutaneous eruption that accompanies a streptococcal infection at another anatomic site. It usually appears 1-4 days after the onset of illness, and appears first on the trunk and axillae before generalizing (shown). The face is usually flushed with a circumoral pallor. This lasts for 4-5 days and is followed by fine desquamation. Complications are varied and include septicemia, vasculitis, hepatitis, and rheumatic fever. Diagnosis is made based on culture. Antibiotic therapy is mandatory. Mortality decreases from 20% to 1% with appropriate antibiotic therapy. Patients should be closely monitored to ensure adequate recovery.
Erysipelas is a superficial bacterial skin infection that characteristically extends into the cutaneous lymphatics. Predisposing factors include recent streptococcal infection, diabetes, alcohol abuse, HIV infection, nephrotic syndrome, or preexisting lymphedema. The initial event is usually inoculation into an area of skin trauma, which leads to a small erythematous patch that progresses to an indurated tense and shiny plaque. Classically, these lesions have sharply demarcated margins. The infection rapidly spreads through the lymphatic vessels, which can produce skin "streaking," regional lymph node swelling, and tenderness. Infections on the face are usually caused by Streptococcus pyogenes; those of the legs are caused by non-group A streptococci. Recurrent infections may cause disfiguring and disabling healing reactions. The diagnosis is typically clinical, and penicillin is the first line of therapy.
Tinea capitis is a superficial fungal infection of the scalp, eyebrows, and eyelashes with a propensity for attacking hair shafts and follicles. It is the most common pediatric dermatophyte infection worldwide caused by the fungi genera Trichophyton and Microsporum. The most common population affected is school-aged African American male children. Infection usually begins as a small erythematous papule around a hair shaft as the hyphae grow centrifugally in the stratum corneum. This becomes progressively paler and scaly within a few days, as the hair appears discolored, lusterless, and brittle. The lesions then spread, producing numerous ring-like papules (shown). Alopecia and pruritus are common.
Inflammation in tinea capitis may range from mild to severe. Deep, boggy areas of severe acute inflammation with pustule formation are termed kerions (shown). There are 3 distinct patterns of hair invasion in tinea capitis. Ectothrix infection is the fragmentation of mycelium around the hair shaft or just beneath the cuticle. This destroys the cuticle; infected hairs will fluoresce under Wood's lamp illumination. These lesions may heal without scarring. Endothrix infection occurs when arthrospores are present within the hair shaft during both the anagen and telogen phases of hair growth. This contributes to chronic infections. Infected hairs do not fluoresce under Wood's lamp. Favus is a severe form of chronic infection in which crusts develop and there is severe hair loss. These infections tend to cluster in families and are common in Africa, the Mediterranean, and the Middle East. Diagnosis for all forms of tinea capitis is typically clinical, but formal diagnosis, including species identification, is made by examination and culture of scrapings. Treatment is typically with systemic antifungal medications supplemented with the addition of ketoconazole shampoo. Image courtesy of Skin Diseases in Chinese by Yau-Chin Lu, MD. Permission granted by Medicine Today Publishing Co.; Taipei, Taiwan; 1981.
Author
Aimee M. Barton, MD
Assistant Professor, Department of Pediatrics
Division of Neonatology
Georgetown University Medical Center
Washington, DC
Disclosure: Aimee M. Barton, MD, has disclosed no relevant financial relationships.
Editor
Lars Grimm, MD, MHS
House Staff
Department of Internal Medicine
Duke University Medical Center
Durham, North Carolina
Disclosure: Lars Grimm, MD, MHS, has disclosed no relevant financial relationships.
Reviewer
Robert A. Schwartz, MD
Professor and Head, Dermatology
Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health
UMDNJ-New Jersey Medical School
Newark, New Jersey
Disclosure: Robert A. Schwartz, MD, has disclosed no relevant financial relationships.
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