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Rash in Infants and Young Children

by Deborah M. Consolini, MD

Rash is a common complaint, particularly during infancy. Most rashes are not serious.

Etiology

Rashes can be caused by infection (viral, fungal, or bacterial), contact with irritants, atopy, drug hypersensitivity, other allergic reactions, inflammatory conditions, or vasculitides (see Some Causes of Rash in Infants and Children).

Overall, the most common causes of rash in infants and young children include

  • Diaper rash (with or without candidal infection)

  • Seborrhea

  • Eczema

  • Viral exanthem

Numerous viral infections cause rash. Some (eg, chickenpox, erythema infectiosum, measles) have a fairly typical appearance and clinical manifestation; others are nonspecific. Cutaneous drug reactions are usually self-limited maculopapular exanthems, but sometimes more serious reactions occur.

Uncommon but serious causes of rash include

  • Staphylococcal scalded skin syndrome

  • Meningococcemia

  • Kawasaki disease

  • Stevens-Johnson syndrome

Some Causes of Rash in Infants and Children

Cause

Suggestive Findings

Diagnostic Approach

Infections

Candidal infections

Beefy red rash with adjacent satellite lesions in the diaper area, including skin creases

Often fluffy white plaques on the tongue or oral mucosa

Sometimes history of recent antibiotic use

Clinical evaluation

Sometimes scrapings of lesions for KOH wet mount

Chickenpox*

Red dots on the face, scalp, torso and proximal extremities that progress over 10–12 h to small bumps, vesicles, and then umbilicated pustules, which form crusts

Intensely itchy blisters, which may also occur on the palms, soles, scalp, and mucous membranes, as well as in the diaper area

Clinical evaluation

Erythema infectiosum

Confluent erythema on cheeks (slapped cheek appearance)

Sometimes fever, malaise

Clinical evaluation

Impetigo

Nonbullous impetigo: Painless but itchy red sore near the nose or mouth that soon leaks pus or fluid and forms a honey-colored scab

Bullous impetigo: Occurs mainly in children < 2 yr

Painless, fluid-filled blisters—mostly on the arms, legs, and trunk, surrounded by red and itchy skin—which, after breaking, form yellow or silvery scabs

Clinical evaluation

Lyme disease

Erythema migrans rash; an enlarging (to about 5–7 cm) erythematous lesion sometimes with central clearing or rarely purpura (2%)

Often fatigue, headache, joint or body aches

Usually in endemic area with risk of exposure to ticks, with or without a known tick bite

Clinical evaluation

Sometimes serologic testing

Measles*

Maculopapular rash beginning on the face and spreading to the trunk and extremities

Often Koplik spots (white spots on buccal mucosa)

Fever, cough, coryza, conjunctival injection

Clinical evaluation

Serologic testing (for public health reasons)

Meningococcemia

Petechial rash, sometimes with purpura fulminans

Fever, lethargy, irritability

In older children, meningeal signs

Tachycardia, sometimes hypotension

Gram stain and culture of blood and CSF

Molluscum contagiosum

Clusters of flesh-colored, umbilicated papules

No itching or discomfort

Clinical evaluation

Roseola infantum

Maculopapular rash that appears suddenly after 4 or 5 days of high fever, typically as fever resolves

Clinical evaluation

Rubella*

Sometimes itchy rash that begins on the face and spreads downward, appears as pink or light red spots (which may merge to form evenly colored patches), and usually clears on the face as it spreads

Lasts up to 3 days

Often lymphadenopathy (occipital, postauricular, posterior cervical), mild fever

Clinical evaluation

Serologic testing (for public health reasons)

Scarlet fever (scarlatina)

Fever, sometimes sore throat

Generalized fine, red, rough-textured, blanching rash that typically appears 12–72 h after the fever and starts on the chest, in the armpits, and on the groin

Characteristic pale area around the mouth (circumoral pallor) and accentuation in the skinfolds (Pastia lines), strawberry tongue

Often followed by extensive desquamation of the palms and soles, tips of fingers and toes, and groin

Clinical evaluation

Sometimes rapid streptococcal assay or throat culture

Staphylococcal scalded skin syndrome

Widespread areas of painful erythema that develop large, flaccid blisters, which are easily ruptured, leaving large areas of desquamation

Lateral extension of blisters with gentle pressure (positive Nikolsky sign)

Spares the mucous membranes

Usually in children < 5 yr

Clinical evaluation

Sometimes confirmed by biopsy and/or cultures

Tinea

Scaly, oval lesions with a slightly raised border and central clearing

Mild itching

Clinical evaluation

Sometimes scrapings of lesions for KOH wet mount

Viral infection (systemic)

Maculopapular rash

Often viral respiratory prodrome

Clinical evaluation

Hypersensitivity reactions

Atopic dermatitis (eczema)

Chronic or recurrent red, scaly patches, often in flexor creases

Sometimes family history

Clinical evaluation

Contact dermatitis

Intensely itchy erythema, sometimes with vesicles

No systemic manifestations

Clinical evaluation

Drug reaction

Diffuse maculopapular rash

History of current or recent (within 1 wk) drug use

Clinical evaluation

Stevens-Johnson syndrome

Toxic epidermal necrolysis

Prodrome of fever, malaise, cough, sore throat, and conjunctivitis

Painful mucosal ulcers, almost always in the mouth and lips but sometimes in the genital and anal regions

Widespread areas of painful erythema that develop large, flaccid blisters, which are easily ruptured, leaving large areas of desquamation; possibly affecting the soles but usually not the scalp

Lateral extension of blisters with gentle pressure (positive Nikolsky sign)

Sometimes use of a causative drug (eg, sulfonamides, penicillins, anticonvulsants)

Clinical evaluation

Sometimes biopsy

Urticaria

Well-circumscribed, pruritic, red, raised lesions

With or without history of exposure to known or potential allergens

Clinical evaluation

Vasculitides

Immunoglobulin A–associated vasculitis (formerly called Henoch-Schönlein purpura)

Palpable purpura appearing in crops over days to weeks, typically in dependent areas (eg, legs, buttocks)

Often arthritis, abdominal pain

Sometimes hematuria, heme-positive stool, and/or intussusception

Usually in children < 10 yr

Clinical evaluation

Sometimes skin biopsy

Kawasaki disease

Diffuse erythematous maculopapular rash that can vary in appearance (eg, urticarial, target-like, purpuric) but never bullous or vesicular; may involve the palms and/or soles

Fever (often > 39° C) for > 5 days

Red, cracked lips, strawberry tongue, conjunctivitis, cervical lymphadenopathy

Edema of hands and feet

Later desquamation of fingers and toes extending to palms and soles

Clinical criteria

Testing to exclude other disorders

Other

Seborrheic dermatitis

Red and yellow scaling on the scalp (cradle cap) and sometimes in skinfolds

Clinical evaluation

Diaper rash (noncandidal)

Bright red rash in the diaper area, sparing creases

Clinical evaluation

Hemolytic-uremic syndrome

Petechial rash, pallor

Usually during or after infectious colitis manifesting with abdominal pain, vomiting, and bloody diarrhea

Oliguria or anuria

Hypertension

CBC with platelets and peripheral smear to check for evidence of microangiopathic anemia and thrombocytopenia

Renal function tests

Stool testing (Shiga toxin assay or specific culture for E. coli O157:H7)

Milia

Small pearly cysts on a neonate's face

Clinical evaluation

Erythema multiforme

Pink-red blotches, symmetrically arranged and starting on the extremities, then evolving into the classic target-like lesion with a pink-red ring around a pale center

Sometimes oral mucosal lesions, pruritis

Clinical evaluation

Miliaria (heat rash)

Small red bumps or occasionally small blisters

Most common in very young children but can occur at any age, particularly during hot and humid weather

Clinical evaluation

Erythema toxicum

Flat red splotches (usually with a white, pimple-like bump in the middle), which appear in up to half of all babies

Rarely appears after 5 days of age and is usually gone in 7–14 days

Clinical evaluation

Neonatal acne

Red bumps, sometimes with white dots in the center on a neonate's face

Usually occurs between 2 and 4 wk after birth but may appear up to 4 mo after birth and can last for 12–18 mo

Clinical evaluation

Pityriasis rosea

Sometimes URI prodrome

Typically begins as a single, pruritic 2- to 10-cm oval red herald patch on the trunk or proximal limbs

7–14 days after the herald patch, appearance of large patches of pink or red, flaky, oval-shaped rash on the torso, sometimes in a characteristic Christmas tree–like distribution

Clinical evaluation

*Currently uncommon because of vaccination but should be considered in unvaccinated children.

KOH = K hydroxide.

Evaluation

History

History of present illness focuses on the time course of illness, particularly the relationship between the rash and other symptoms.

Review of systems focuses on symptoms of causative disorders, including GI symptoms (suggesting immunoglobulin A–associated vasculitis [formerly called Henoch-Schönlein purpura] or hemolytic-uremic syndrome), joint symptoms (suggesting immunoglobulin A–associated vasculitis or Lyme disease), headache or neurologic symptoms (suggesting meningitis or Lyme disease).

Past medical history should note any drugs recently used, particularly antibiotics and anticonvulsants. Family history of atopy is noted.

Physical examination

Examination begins with a review of vital signs, particularly to check for fever. Initial observation assesses the infant or child for signs of lethargy, irritability or distress. A full physical examination is done, with particular attention to the characteristics of the skin lesions (see Description of Skin Lesions), including the presence of blistering, vesicles petechiae, purpura or urticaria, and mucosal involvement. Children are evaluated for meningeal signs (neck stiffness, Kernig and Brudzinski signs) although these signs are often absent in children < 2 yr.

Red flags

The following findings are of particular concern:

  • Blistering or skin sloughing

  • Diarrhea and/or abdominal pain

  • Fever and inconsolability or extreme irritability

  • Mucosal inflammation

  • Petechiae and/or purpura

  • Urticaria with respiratory distress

Interpretation of findings

Well-appearing children without systemic symptoms or signs are unlikely to have a dangerous disorder. The appearance of the rash typically narrows the differential diagnosis. The associated symptoms and signs help identify patients with a serious disorder and often suggest the diagnosis (see Some Causes of Rash in Infants and Children).

Bullae and/or sloughing suggest staphylococcal scalded skin syndrome or Stevens-Johnson syndrome and are considered dermatologic emergencies. Conjunctival inflammation may occur in Kawasaki disease, measles, staphylococcal scalded skin syndrome, and Stevens-Johnson syndrome. Any child presenting with fever and petechiae or purpura must be evaluated carefully for the possibility of meningococcemia. Bloody diarrhea with pallor and petechiae should raise concern about the possibility of hemolytic uremic syndrome. Fever for > 5 days with evidence of mucosal inflammation and rash should prompt consideration of and further evaluation for Kawasaki disease.

Testing

For most children, the history and physical examination are sufficient for diagnosis. Testing is targeted at potential life threats; it includes Gram stain and cultures of blood and CSF for meningococcemia; CBC, renal function tests, and stool tests for hemolytic uremic syndrome).

Treatment

Treatment is directed at the cause (eg, antifungal cream for candidal infection).

For diaper rash, the goal is to keep the diaper area clean and dry, primarily by changing diapers more frequently and gently washing the area with mild soap and water. Sometimes a barrier ointment containing zinc oxide or vitamins A and D may help.

Pruritus in infants and children can be lessened by oral antihistamines:

  • Diphenhydramine: For children > 6 mo, 1.25 mg/kg q 6 h (maximum 50 mg q 6 h)

  • Hydroxyzine: For children > 6 mo, 0.5 mg/kg q 6 h (maximum for children < 6 yr, 12.5 mg q 6 h; for those ≥ 6 yr, 25 mg q 6 h)

  • Cetirizine: For children 6 to 23 mo, 2.5 mg once/day; for those 2 to 5 yr, 2.5 to 5 mg once/day; for those > 6 yr, 5 to 10 mg once/day

  • Loratadine: For children 2 to 5 yr, 5 mg once/day; for those > 6 yr, 10 mg once/day

Key Points

  • Most rashes in children are benign.

  • For most rashes in infants and children, the history and physical examination are sufficient for diagnosis.

  • Children with rash due to serious illness typically have systemic manifestations of disease.

Resources In This Article

Drugs Mentioned In This Article

  • Drug Name
    Select Trade
  • ALAVERT, CLARITIN
  • VISTARIL
  • ZYRTEC
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* This is a professional Version *