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 Table: Some Causes of Rash in Infants and Children).
The photo shows lesions of molluscum contagiosum. Lesions are typically 1 to 5 mm, solitary or grouped, firm, painless papules. They are pearly to pink in color, dome shaped, and may be umbilicated.
This photo shows very severe lesions on the face of a child infected with HIV. Giant molluscum indicates advanced immunodeficiency.
This photo shows irritant diaper dermatitis (“W-dermatitis”).
This photo shows severe diaper dermatitis due to neglect.
Erythema multiforme is characterized by target or iris lesions, which are annular lesions with a violaceous center and pink halo separated by a pale ring.
This photo shows small, pearl-colored cysts commonly seen on the face of neonates.
This photo shows fluffy white exudate on the tongue of an HIV-infected child.
Atopic dermatitis usually develops in infancy. In the acute phase, lesions appear on the face and then spread to the neck, scalp, and extremities.
This photo shows allergic contact dermatitis on the forearm of a child after a temporary, black "henna" tattoo was applied.
Skin manifestations of allergic contact dermatitis range from erythema through vesiculation to edema with bullae, ulceration, or both. Changes often occur in a pattern or distribution that suggests a specific exposure; in this image, linear streaking on an extremity suggests plant contact (eg, poison ivy or poison sumac).
Overall, the most common causes of rash in infants and young children include
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
Some Causes of Rash in Infants and Children
Cause |
Suggestive Findings |
Diagnostic Approach |
Infections |
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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 potassium hydroxide wet mount |
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Red dots on the face, scalp, torso and proximal extremities that progress over 10–12 hours 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 |
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Confluent erythema on cheeks (slapped-cheek appearance) Sometimes fever, malaise |
Clinical evaluation |
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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 years 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 |
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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 |
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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) |
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Petechial rash, sometimes with purpura fulminans Fever, lethargy, irritability In older children, meningeal signs Tachycardia, sometimes hypotension |
Gram stain and culture of blood and cerebrospinal fluid |
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Clusters of flesh-colored, umbilicated papules No itching or discomfort |
Clinical evaluation |
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Maculopapular rash that appears suddenly after 4 or 5 days of high fever, typically as fever resolves |
Clinical evaluation |
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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) |
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Scarlet fever (scarlatina) |
Fever, sometimes sore throat Generalized fine, red, rough-textured, blanching rash that typically appears 12–72 hours 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 |
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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 years |
Clinical evaluation Sometimes confirmed by biopsy and/or cultures |
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Scaly, oval lesions with a slightly raised border and central clearing Mild itching |
Clinical evaluation Sometimes scrapings of lesions for potassium hydroxide wet mount |
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Viral infection (systemic) |
Maculopapular rash Often viral respiratory prodrome |
Clinical evaluation |
Hypersensitivity reactions |
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Atopic dermatitis (eczema) |
Chronic or recurrent red, scaly patches, often in flexor creases Sometimes family history |
Clinical evaluation |
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Intensely itchy erythema, sometimes with vesicles No systemic manifestations |
Clinical evaluation |
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Diffuse maculopapular rash History of current or recent (within 1 week) drug use |
Clinical evaluation |
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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 |
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Well-circumscribed, pruritic, red, raised lesions With or without history of exposure to known or potential allergens |
Clinical evaluation |
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Vasculitides |
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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 years |
Clinical evaluation Sometimes skin biopsy |
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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 |
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Other |
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Red and yellow scaling on the scalp (cradle cap) and sometimes in skinfolds |
Clinical evaluation |
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Diaper rash (noncandidal) |
Bright red rash in the diaper area, sparing creases |
Clinical evaluation |
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Petechial rash, pallor Usually during or after infectious colitis manifesting with abdominal pain, vomiting, and bloody diarrhea Oliguria or anuria Hypertension |
Complete blood count 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) |
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Small pearly cysts on a neonate's face |
Clinical evaluation |
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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 |
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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 |
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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 |
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Neonatal acne |
Red bumps, sometimes with white dots in the center on a neonate's face Usually occurs between 2 and 4 weeks after birth but may appear up to 4 months after birth and can last for 12–18 months |
Clinical evaluation |
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Sometimes upper respiratory infection 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 |
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* This cause is currently uncommon because of vaccination but should be considered in unvaccinated children. |
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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 gastrointestinal 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, 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 years.
Red flags
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 Table: 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 cerebrospinal fluid for meningococcemia; complete blood count, renal function tests, and stool tests for hemolytic uremic syndrome).
Treatment
Treatment of rash 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:
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Diphenhydramine: For children > 6 months, 1.25 mg/kg every 6 hours (maximum 50 mg every 6 hours)
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Hydroxyzine: For children > 6 months, 0.5 mg/kg every 6 hours (maximum for children < 6 years, 12.5 mg every 6 hours; for those ≥ 6 years, 25 mg every 6 hours)
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Cetirizine: For children 6 to 23 months, 2.5 mg once a day; for those 2 to 5 years, 2.5 to 5 mg once a day; for those > 6 years, 5 to 10 mg once a day
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Loratadine: For children 2 to 5 years, 5 mg once a day; for those > 6 years, 10 mg once a day
Some common adverse effects of antihistamines include dry mouth, drowsiness, dizziness, nausea and vomiting, restlessness or moodiness (in some children), urinary hesitancy, blurred vision, and confusion.
