Dermatologic Conditions

Parents can be alarmed when their child develops a rash, but many pediatric exanthems can be treated with time and reassurance. This section covers the following viral exanthems and other dermatologic conditions that are common in the urgent care setting:

• Viral Exanthems

  • Hand, Foot, and Mouth Disease

  • Fifth Disease

  • Roseola Infantum

  • Measles

  • Rubella

• Pityriasis Rosea

• Erythema Multiforme

• Scarlet Fever

Other exanthems and skin lesions pertinent to pediatric urgent care are covered in the following rotation guides:

• Cutaneous Infections (Pediatric Dermatology)

  • Molluscum Contagiosum

  • Scabies

  • Dermatophytosis

  • Tinea Versicolor

  • Warts

• Contact Dermatitis (Pediatric Dermatology)

• Urticaria and Angioedema (Pediatric Allergy and Immunology)

Viral Exanthems

Viruses often manifest as a rash in the pediatric population; some are well-defined and easily recognizable, others are nonspecific. In this section, we review a few of the most common pediatric viral exanthems.

Hand, Foot, and Mouth Disease

Hand, foot, and mouth disease (HFMD) is caused by enteroviruses, most commonly coxsackie virus A16.

Presentation: Initial symptoms are fever and decreased appetite, followed by the development of an oral enanthem, usually in the posterior oropharynx. Patients also develop a maculopapular exanthem on the palms, soles, and genitourinary region. The oral lesions are often painful, leading to decreased dietary intake.

Management: HFMD is usually mild in severity and can be managed at home with supportive care. Severe cases may lead to dehydration requiring intravenous (IV) fluids or may be associated with aseptic meningitis or encephalitis.

Diagnosis: Although HFMD is generally a clinical diagnosis, enterovirus polymerase chain reaction (PCR) testing can assist with the diagnosis.

(Source: Hand, Foot, and Mouth Disease. N Engl J Med 2010.)

(Source: NEJM Knowledge+ 2021.)

Fifth Disease (Erythema Infectiosum)

Fifth disease is a viral infection due to parvovirus B19.

Presentation: In a healthy child, fifth disease presents initially with fever and cold symptoms that resolve, followed by development of the classic “slapped cheek” rash with circumoral pallor. After a few days, the rash spreads to the trunk and extremities with a reticular or lacelike appearance. The rash can change in intensity based on temperature and sunlight exposure. Some children develop polyarthropathy, but this is more common in adults.

Less frequently, parvovirus B19 can also present as papular-purpuric gloves-and-socks syndrome. This is a painful pruritic rash with development of purpura of the hands and feet. Parvovirus B19 can also cause transient aplastic crises in patients with conditions such as sickle cell disease and thalassemia. Maternal infection with fifth disease during pregnancy can lead to severe anemia in the fetus and cause hydrops fetalis (a buildup of fluid).

Diagnosis is clinical but can be confirmed with a parvovirus B19 immunglobulin M (IgM) antibody or PCR if clinically indicated.

Management is with supportive care.

“Slapped cheek” appearance in fifth disease.

(Photographs courtesy of Amy Pattishall, MD)

Roseola Infantum (Sixth Disease)

Roseola infantum, or sixth disease, is a common viral infection in infants due to human herpesvirus 6 and occasionally human herpesvirus 7.

Presentation: The classic presentation is in a child younger than 3 years with isolated high fever for about 3 days. Other concomitant features include mild upper respiratory symptoms, erythema of the tympanic membranes, postoccipital lymphadenopathy, and mild irritability. Children may also be asymptomatic aside from the fever. Resolution of the fever is followed by the development of a diffuse, erythematous, maculopapular rash that begins on the trunk and spreads to the extremities.

Diagnosis: Roseola is diagnosed clinically and is difficult to diagnose prior to the onset of the rash. Some patients develop febrile seizures due to the high fever.

Management is with supportive care; the rash resolves spontaneously after a few days.

(Source: Sixth Disease and the Ubiquity of Human Herpesviruses. N Engl J Med 2005.)

Measles

Measles is a highly contagious virus transmitted via contact, droplets, or airborne spread. Widespread vaccination, beginning in the 1960s, led to a significant decrease in the incidence of measles. However, starting in the 2000s, a decline in vaccination rates has led to the resurgence of measles. Measles is of particular concern in unvaccinated children, during an outbreak, and in families who travel internationally or who live in a community of people with a history of overseas travel.

(Source: Measles (Rubeola). Centers for Disease Control and Prevention. Accessed August 7, 2024.)

Presentation

• fever with cough

• coryza

• conjunctivitis

• Koplik spots (present prior to the onset of the rash and fade as the rash begins)

  • Many children develop white papules that have a bluish-white center, generally appearing on the buccal surfaces of the oral mucosa.

• diffuse rash (develops as Koplik spots fade)

  • The exanthem is characterized as a morbilliform rash that starts on the forehead and spreads caudally. The rash will remain for 3-5 days and will disappear in the same fashion as it appeared.

(Source: Measles. N Engl J Med 2019.)

Complications include:

• acute otitis media

• croup

• pneumonia

• diarrhea

• acute encephalitis (with increased risk for permanent neurological injury)

  • Infection from wild-type measles is associated with increased risk of developing subacute sclerosing panencephalitis — a rare degenerative neurologic condition — about 10 years postinfection.

Management

• Management is mainly with supportive care and vitamin A supplementation.

• In health care settings, patients suspected of having measles should be masked and placed in airborne isolation.

• Health care personnel should use N95 respirators upon entry to a patient’s room.

• Measles is a reportable disease to the CDC’s National Notifiable Diseases Surveillance System (NNDSS).

• Post-exposure prophylaxis should be given within 72 hours after exposure. Immunoglobulin (rather than vaccination) is indicated for those at risk of severe disease, including pregnant women without known immunity, severely immunocompromised patients, and infants <12 months of age.

Rubella

Rubella is transmitted via droplets and nasal secretions. Vaccination is very effective and leads to lifelong immunity.

Presentation

• Postnatally acquired rubella manifests as low-grade fever, rash, and lymphadenopathy. Postauricular or occipital lymphadenopathy may be present prior to the onset of the rash. The rash associated with rubella is maculopapular and spreads caudally from the face to the trunk and extremities. Although the pattern of the rash is similar to the measles rash, the spread is much more rapid and described to be more intensely erythematous or even purpuric. Other symptoms include an enanthem on the soft palate called Forchheimer spots.

  • Complications include postinfectious encephalitis, meningitis, arthritis, and orchitis.

• Congenital rubella syndrome consists of various anomalies of the ophthalmologic, cardiac, auditory, and neurologic systems. The most commonly described findings are congenital cataracts or congenital glaucoma, patent ductus arteriosus, sensorineural hearing loss, encephalitis, microcephaly, or developmental delay. Complications include arthritis, hemorrhagic purpura, and meningitis. For more on congenital rubella, see Congenital Infections in the Pediatrics Infectious Diseases rotation guide.

Laboratory testing with rubella-specific IgM antibodies is suggested if there is concern for congenital rubella or if the patient develops complications.

Management is mainly with supportive care.

(Source: Rubella [German Measles, Three-Day Measles]. Centers for Disease Control and Prevention. Accessed September 2023.)

(Source: Forchheimer Spots in Rubella. Intern Med 2020.)

Pityriasis Rosea

Pityriasis rosea is more common in adolescents and rare in children younger than 5 years. The cause is unknown but is thought to be secondary to a viral infection.

Presentation: The rash is often pruritic and appears as oval, pink lesions with peripheral scaling in a Christmas tree distribution along the body, following the skin cleavage lines of the trunk and back while sparing the face, scalp, and distal extremities. It is often preceded by a herald patch, which is a large, oval solitary lesion that is frequently misdiagnosed as tinea corporis or ringworm.

Management is with supportive care. Oral antihistamines or topical emollients are recommended for pruritus. The rash will spontaneously regress within a few weeks.

Diagnosis: The differential diagnosis includes tinea corporis (in the herald patch phase) and secondary syphilis, especially if the rash appears on the patient’s palms and soles.

Images of pityriasis rosea can be found here.

Erythema Multiforme

Erythema multiforme (EM) is an immune-mediated inflammatory skin reaction. It generally occurs after a viral infection, most commonly after herpes simplex virus. Other causes include infection with Mycoplasma pneumoniae or treatment with antibiotics, anticonvulsants, or other medications.

Presentation: The rash appears as red macules that transition into target-shaped lesions and appear mainly on the dorsum of the hands and extensor surfaces of the body. Patients commonly report that the lesions are painful rather than pruritic. Although sloughing of the epidermis may occur, it should not exceed 10% of body surface area.

EM can be further classified as EM minor and EM major. EM major is the diagnosis of EM with mucosal involvement, which can include oral mucosa, conjunctiva, urethra, and vagina.

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are more-severe hypersensitivity reactions that can be caused by medications or infection. It is unclear if these entities represent a continuum of disease with EM, but mucous membrane involvement should prompt consideration for development of these life-threatening illnesses.

(Source: NEJM Knowledge+ 2021.)

Management is supportive with antipyretics and antihistamines. If a medication that led to EM is known, it should be discontinued.

(Source: Public Health Image Library (PHIL). Centers for Disease Control. Brian Hill, New Zealand 1976.)

(Source: Case 34-2005 — A 10-Year-Old Girl with a Bullous Skin Eruption and Acute Respiratory Failure. N Engl J Med 2005.)

Scarlet Fever (Scarlatina)

Scarlet fever is a diffuse, erythematous, sandpaper-like papular rash and fever associated with group A streptococcal (GAS) infection as a delayed-type skin reaction.

Presentation: The papules are 1-2 mm in size and numerous in quantity, often starting in the groin and axilla and spreading to the trunk and extremities. A strawberry tongue is also often present. The rash may desquamate or peel. Pastia lines, or accentuation of the rash in flexoral creases, may also be present, especially in the groin, axilla, and elbow creases. Note that the rash spares the palms and soles. The rash is typically associated with pharyngitis.

Diagnosis is made based on clinical presentation and can be confirmed with a pharyngeal strep test.

Treatment is the same as for GAS pharyngitis (see the ENT section in this rotation guide).

(Source: Scarlet Fever. N Engl J Med 2017.)