Infectious rashes in childhood

Summary

Infectious rashes are common in children and are caused by viruses, bacteria, fungi, or parasites. In acutely ill patients, perform initial management of rash to identify red flags for a life-threatening rash. A detailed history and skin examination are essential in all patients, as infectious rashes can often be diagnosed clinically. Diagnostic testing may be obtained to confirm certain diagnoses (e.g., measles, rubella, bacterial or fungal infections) and to exclude alternative diagnoses in case of diagnostic uncertainty. Management is based on the underlying cause. Most viral infections are managed with supportive care. Pharmacological treatment with antibiotics, antivirals, or ectoparasiticides may be indicated depending on the causative organism.

For information on rashes associated with congenital infections, see “Congenital TORCH infections.” For more information on each specific infection, see the respective articles.

**Chalk Talk: Pediatric rashes - Part 1**
© AMBOSS

Etiology

Viral [1][2][3]

Chickenpox
Hand, foot, and mouth disease [4]
Measles
Erythema infectiosum (Fifth disease)
Roseola infantum
Rubella
Molluscum contagiosum
Herpes simplex virus infections [5]
Shingles
Gianotti-Crosti syndrome
Dengue
Zika virus
Chikungunya virus
Acute HIV exanthem [6]
Nonspecific viral exanthems [6]

Bacterial [1][6]

Scarlet fever
Skin and soft tissue infections, e.g.:
- Impetigo [2]
- Staphylococcal scalded skin syndrome
- Folliculitis
Meningococcal septicemia
Lyme disease
Rocky Mountain spotted fever (RMSF)
Toxic shock syndrome
Disseminated gonococcal infection [3]

Fungal [1]

Dermatophyte infections
Candidiasis
Pityriasis versicolor

Parasitic [1]

Scabies
Lice

Clinical evaluation

Focused history [2][6]

Rash characteristics
- Onset, duration, progression
- Distribution
Associated symptoms
- Constitutional symptoms (e.g., fever)
- Pruritus
- Arthralgias
- Pharyngitis
Exposures
- New medications or products
- Recent travel
- Sick contacts
- Arthropod bites

Focused examination [2][6]

Vital signs: to assess for fever
General appearance: to assess for irritability or lethargy
Lymph node examination
Skin examination: See “
Primary skin lesions” and “
Secondary skin lesions” for describing and documenting rashes.

Determine lesion morphology (e.g., macules, papules, vesicles, pustules).

Examine the entire skin and mucosa to determine rash distribution.

Describe additional lesion characteristics (e.g., color, presence of scale or Nikolsky sign, blanchable).

Diagnostics

Approach [1][2][6]

Acute illness: Perform initial management of rash, including identifying red flags for a life-threatening rash.
Ensure appropriate isolation precautions (e.g., for suspected measles or meningococcal septicemia).
In children, diagnosis is usually clinical.
Obtain
laboratory studies as needed to:
- Identify pathogen for diagnostic confirmation
- Exclude alternative diagnoses (see “Mimics”)
Consider biopsy to rule out mimics in case of diagnostic uncertainty.

Laboratory studies [1][6]

CBC: to identify leukocytosis, thrombocytopenia
Microbiological studies: to identify causative organism based on clinical suspicion
- Diagnostics for scarlet fever (e.g., rapid strep test, throat culture)
- Diagnostics for measles (e.g., measles-specific antibodies, RT-PCR)
- Diagnostics for rubella (e.g., rubella-specific antibodies, RT-PCR)
- Diagnostics for dermatophyte infections (e.g., KOH test, fungal culture)
- Diagnostics for HSV infections (e.g., PCR, viral culture)
- Diagnostics for RMSF (e.g., Rickettsia antibody panels)
- Diagnostics for Lyme disease (e.g., Lyme antibody testing)
- Diagnostics for meningitis in children (e.g., blood and CSF cultures)

Common causes

Common causes of infectious rash in children [1][2][7][8]
Disease (pathogen)	Characteristic clinical features		Management
Measles (Measles virus)		Prodrome Coryza, cough, and conjunctivitis Koplik spots Fever Erythematous, blanching rash with macules and papules Begins on the face, frequently behind the ears Spreads to the rest of the body Possible desquamation	Airborne precautions Serology or PCR to confirm the diagnosis Supportive care Vitamin A supplementation in selected patients See “Management of measles.”
Scarlet fever (Streptococcus pyogenes)		Prodrome of fever, tonsillopharyngitis Fine, erythematous blanching rash with macules and papules (sandpaper-like texture) Begins on the neck or trunk and spreads rapidly across the body [9] Desquamation 7–10 days after rash resolves Strawberry tongue Pastia lines Flushed cheeks, perioral pallor	Rapid strep test or throat culture to confirm the diagnosis Antibiotics for GAS pharyngitis See “Treatment of scarlet fever.”
Rubella (Rubella virus)		Prodrome Mild nonspecific symptoms, low-grade fever Suboccipital and postauricular lymphadenopathy Forchheimer sign Fine, erythematous rash with macules and papules Begins on the face and spreads to the trunk and extremities Nonconfluent, medium-sized spots	Droplet precautions Serology or PCR to confirm the diagnosis See “Management of rubella.”
Fifth disease (erythema infectiosum) (Parvovirus B19)		Prodrome of systemic symptoms, arthralgias Initial slapped cheek appearance Rash on trunk and extremities Macules and papules that become confluent (lace-like, reticular appearance) May recur with environmental changes (e.g., sunlight, heat exposure) over weeks to months	Clinical diagnosis Supportive management See “Management of parvovirus B19 infection.”
Roseola infantum (exanthem subitum) (Human herpesvirus 6)		Prodrome Sudden high fever for 3–7 days Nagayama spots Patchy, blanching rose-pink rash with macules and papules Develops as fever subsides Originates on the trunk	Clinical diagnosis Supportive care Management of complications (e.g., febrile seizures) See “Treatment of roseola infantum.”
Chickenpox (varicella) (Varicella zoster virus)		Starry sky: simultaneous occurrence of various stages of rash (e.g., pruritic vesicles on erythematous base, crusted pustules) Starts centrally (trunk, face) and spreads to extremities Mucous membrane involvement (typically oropharyngeal, possibly urogenital)	Clinical diagnosis Supportive care Antiviral therapy for VZV infection in selected patients See “Treatment of chickenpox.”
Hand, foot, and mouth disease (Group A Coxsackievirus)		Painful oral ulcers Rash with macules and papules Becomes vesicular Affects feet and hands	Clinical diagnosis Supportive care
Impetigo [10] (Streptococcus pyogenes, Staphylococcus aureus)		Papules that evolve into vesicles and/or pustules Honey-colored crust Most common on the face and extremities Negative Nikolsky sign	Clinical diagnosis Antibiotics See “Treatment of impetigo.”

Measles and rubella are nationally notifiable diseases in the US. Notify the local health department of any suspected cases. [1]

Infectious rashes in children Measles fact sheet Scarlet fever fact sheet Rubella fact sheet Erythema infectiosum (fifth disease) fact sheet Roseola infantum (sixth disease) fact sheet Chickenpox fact sheet

**Koplik spots**
Numerous tiny white spots on an erythematous background (Koplik spots; examples indicated by arrowheads) are visible on the buccal mucosa.

Koplik spots are pathognomonic for measles infection.

This image is an adaptation. Source of original image: Centers for Disease Control and Prevention (CDC). Original title: “ID#4500”. Created by: CDC. Licensed under Public Domain. Modifications to original image: Image turned.

**Measles rash**
Photograph of a toddler
There is a generalized erythematous maculopapular exanthem. Some confluence is visible (e.g., on the upper thighs).

Source: "Measles rash PHIL", Centers for Disease Control and Prevention, Atlanta,USA, Centers for Disease Control and Prevention licensed under Public Domain

**Skin manifestations in scarlet fever**
The typical scarlet-colored, fine, maculopapular exanthem of scarlet fever is seen on the right arm. Flushed cheeks and perioral pallor are also evident.

Source: “Scarlet Fever” by Badobadop, Wikimedia Commons, licensed under CC BY-SA 3.0. Modifications: Pixelated eyes.

**Desquamation in scarlet fever**
Palms showing lamellar desquamation of the skin ("skin glove"). Desquamation typically begins 7–10 days after rash resolves, and lasts up to 4–6 weeks. The face and trunk typically show pityriasiform scales.

Source: "Scharlach", YasminFeth, Wikimedia Commons licensed under Public Domain

**Strawberry tongue**
The tongue is bright red with prominent edematous papillae and a white coating. This finding is typically seen during the exanthematous phase of scarlet fever, but may also be seen in other conditions such as toxic shock syndrome or Kawasaki disease.

Source: “Scharlach” by Martin Kronawitter, Wikimedia Commons, licensed under CC BY-SA 2.5.

**Rubella rash**
A nonconfluent, pink, maculopapular rash is visible across this infant's trunk and extremities.

Source: "ID#: 4513", CDC, Centers for Disease Control and Prevention (CDC) licensed under Public Domain

**Rubella**
Photograph of the posterior torso of a child
Coalescing red-pink macules with tiny papules are seen on the trunk.
These features are characteristic of a viral exanthem, in this case caused by rubella. In rubella, the rash typically starts in the face and neck region and spreads downwards.

Source: "ID#: 712", CDC, Centers for Disease Control and Prevention licensed under Public Domain

**Erythema infectiosum (fifth disease) fact sheet**
© AMBOSS

**Erythema infectiosum**
The cheeks are bright red (slapped-cheek rash) and a diffuse, red, confluent rash with macules and papules is visible over the body of this infant.
This is the characteristic cutaneous appearance of erythema infectiosum (fifth disease), which is caused by infection with parvovirus B19.

This image is an adaptation. Source of original image: Wikimedia Commons. Original title: “Fifth disease”. Created by: Andrew Kerr. Licensed under Public Domain. Modifications to original image: Pixelated eyes.

**Roseola infantum (sixth disease) fact sheet**
© AMBOSS

**Roseola infantum (exanthem subitum)**
Photograph of a 1-year-old child with recent febrile illness
A patchy, nonpruritic, blanching, erythematous rash with macules and papules can be seen on the trunk and arms. Symptoms manifested one day after the fever resolved.
These features are consistent with roseola infantum.

Source: "Sestamalattia", Emiliano Burzagli, Wikimedia Commons licensed under Public Domain

**Chickenpox (varicella)**
Upper body of a young boy with exanthem showing the simultaneous occurrence of various stages of rash; mainly vesicles and pustules, no crusted erosions. This clinical finding is also referred to as "starry sky" and is typical of chickenpox.

Source: "Varicela Aranzales", Camiloaranzales, Wikimedia Commons licensed under Public Domain

**Facial rash in chickenpox**
The face of the girl shows macules, vesicles, and papules on an erythematous base, as well as erupted vesicles and crusted papules. The simultaneous occurrence of various stages of rash is sometimes described as "starry sky" and is typical of chickenpox.

Source: "ID#: 10486", CDC/ Dr. John Noble, Jr., Centers for Disease Control and Prevention (CDC) licensed under Public Domain

**Chickenpox**
Multiple disseminated papules and vesicles on an erythematous base are visible on this patient's face. Numerous vesicles in the preauricular region appear umbilicated.
These lesions are caused by an infection with varicella zoster virus (VZV).

Source: “Varicelle importante chickenpox” by Grook da oger, Wikimedia Commons, licensed under CC BY-SA 4.0.

**Hand, foot, and mouth disease**
Hands and feet of a 36-year-old male patient
Macular and papular lesions are visible on the inner surface of the hands and feet.
The localization in conjunction with the enanthem of the mucous membranes is typical of hand, foot, and mouth disease.

Source: “Hand Foot Mouth Disease Adult 36Years” by KlatschmohnAcker, Wikimedia Commons, licensed under CC BY-SA 3.0.

**Impetigo**
Confluent scabbed erosions and honey-colored crusts are visible in the perioral region. This appearance is typical of impetigo, which, in this patient, developed secondary to preexisting eczema and immunosuppression caused by HIV infection.

Source: “Figure 3, in: Atlas of Paediatric HIV Infection” by R. E. Oladokun, R. J. Lehloenya, C. Hlela et al., Open books - University of Cape Town, licensed under CC BY-ND 4.0.

**Nonbullous impetigo**
Confluent erosions and honey-colored crusts with an erythematous base are visible on the face, forehead, temporal region, and part of the neck. As in this photo, vesicles may not always be present or noticeable.

Source: © IMPP

**Infectious rashes in children**
Many infectious diseases in children present with a rash (exanthem). The distribution and morphological characteristics of the exanthem allow the diseases to be differentiated from one another.

Measles: Patients present with a dark red, erythematous, maculopapular, partially confluent exanthem, which spreads from behind the ears to the rest of the body.

Scarlet fever: Patients present with a fine, light red rash with sandpaper-like texture. The exanthem begins on the neck or trunk and disseminates to the whole body. Cheeks may be flushed with perioral pallor. In flexural areas (e.g., axilla and groin), the rash may be more pronounced and linear petechiae (Pastia lines) may be present.

Rubella (German measles): Patients typically present with a nonconfluent, pink, maculopapular exanthem, which begins on the face and spreads to the trunk and extremities.

Erythema infectiosum (fifth disease): A confluent, maculopapular rash appears only in ¼ of patients. It may take on a lace-like, reticular appearance over time. Additionally, patients present with diffuse redness of the face with perioral sparing (slapped-cheek rash).

Roseola infantum (sixth disease): 3-7 days of high fever are followed by a sudden decrease in temperature and development of a patchy, blanching rose-pink maculopapular rash. The rash originates on the trunk, and may spread to the face and extremities.

Varicella (chickenpox): The exanthem affects the whole body, typically spreading to the scalp as well. Various stages of the rash occur simultaneously, which leads to the characteristic clinical finding known as “starry sky.”

© AMBOSS

Management

Management depends on the specific cause.

Most viral infections are managed with supportive care.
Pharmacological treatment (e.g., antibiotics, antivirals, ectoparasiticides) may be indicated depending on the causative organism.

Mimics

Pityriasis rosea
Dermatoses
- Atopic dermatitis
- Allergic contact dermatitis
- Irritant contact dermatitis
- Seborrheic dermatitis
Drug hypersensitivity reactions
- Exanthematous drug eruptions
- Drug reaction with eosinophilia and systemic symptoms (DRESS syndrome)
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Acute generalized exanthematous pustulosis
Urticaria
Rosacea
Vasculitides
- Kawasaki disease
- IgA vasculitis
Multisystem inflammatory syndrome in children
Systemic lupus erythematosus

Always consider drug reactions as a potential cause of rash.

References

Committee on Infectious Disease, American Academy of Pediatrics. "Red Book: 2024-2027 Report of the Committee on Infectious Diseases, 33rd Edition". American Academy of Pediatrics. (2024). ISBN: 9781610027373
Allmon A, Deane K, Martin KL. "Common Skin Rashes in Children". Am Fam Physician. 92(3). :211-6. (2015)
Ely JW, Seabury Stone M. "The generalized rash: part I. Differential diagnosis". Am Fam Physician. 81(6). :726-34. (2010)
Saavedra A, et al. "Fitzpatrick's Color Atlas and Synopsis of Clinical Dermatology, Ninth Edition". McGraw Hill Professional. (2023). ISBN: 9781264278022
Weber R. "Pharyngitis". Prim Care. 41(1). :91-98. (2014)
Hartman-Adams H, Banvard C, Juckett G. "Impetigo: diagnosis and treatment". Am Fam Physician. 90(4). :229-35. (2014)
Gonzales Y Tucker RD, Addepalli A. "Fever and Rash". Emerg Med Clin North Am. 42(2). :303-334. (2024)
"Hand, Foot & Mouth Disease". https://web.archive.org/web/20250214215011/https://wwwnc.cdc.gov/travel/yellowbook/2024/infections-diseases/hand-foot-and-mouth-disease
Biesbroeck L, Sidbury R. "Viral exanthems: an update". Dermatol Ther. 26(6). :433-438. (2013)
Ely JW, Seabury Stone M. "The generalized rash: part II. Diagnostic approach". Am Fam Physician. 81(6). :735-9. (2010)