SIGNS AND SYMPTOMS 
History
Obtain a detailed history:
- Age group: Conditions, distribution, and appearance may vary with age
- Development, progression, pattern, and duration of the rash
- Lesions synchronous or asynchronous
- Associated symptoms
- Prodromes—cough, rhinorrhea, pharyngitis, fever, meningismal symptoms, pruritus
- Family history, exposures, immunizations
- Recent travel; insect or arthropod bites
- Medications especially new medications
- Generic dermatoses
- Atopic dermatitis; psoriasis
Physical Exam
- Cardiac:
- Pulmonary:
- Abdominal:
- Tenderness
- Hepatosplenomegaly
- Skin: See Essential Workup.
ESSENTIAL WORKUP
Classify the rash based on the primary lesions:
- Papulosquamous
- Vesicobullous
- Purpuric
DIAGNOSIS TESTS & INTERPRETATION
Lab
- Indicated if the rash is purpuric:
- Indicated if fever present:
- CBC
- Electrolytes, BUN, creatinine to evaluate dehydration and scarlatiniform rash (exclude glomerulonephritis)
- Viral culture and titers for suspected exanthems
- Lactate and blood cultures for suspected sepsis/bacteremia
- Lumbar puncture if meningococcus or other meningitides or encephalitis suspected
Imaging
Chest radiograph for suspected pulmonary involvement
Diagnostic Procedures/Surgery
- Potassium hydroxide (KOH) preparations:
- Indicated with scaling lesions to differentiate dermatophytosis from nummular eczema and pityriasis rosea
- Superficial scale sample from active border of lesion removed from the skin with a scalpel or the edge of a glass slide
- Place on a slide and add 1 drop of 10% KOH.
- Place a coverslip and heat slowly without boiling. Allow to set for a few minutes and scan for hyphae.
- Wood lamp:
- Useful in dermatophytosis and erythrasma
- Scabies preparations:
- Most of the mite population resides on the hands and feet.
- Place a drop of mineral oil on the lesion. Scrape with a no. 15 blade to produce speck of blood.
- Examine under low power for the mite, ova, larva, or fecal matter.
DIFFERENTIAL DIAGNOSIS
Maculopapular Rash
- Solid, skin colored, or yellow:
- Keratotic
- Wart
- Corn or callus
- Nonkeratotic
- Molluscum contagiosum
- Sebaceous cyst
- Basal and squamous cell carcinoma
- Nevi
- Solid, brown:
- Café au lait patch
- Nevi
- Freckle
- Melanoma
- Photoallergic/phototoxic drug eruption
- Tinea nigra palmaris hypopigmentation
- Solid, red, nonscaling:
- Solid, red, scaling:
- Without epithelial disruption:
- With epithelial disruption:
Pustular
[Outline]
PRE-HOSPITAL
Field management is indicated when there are signs of systemic instability:
- Airway management using precautions to avoid exposure to respiratory secretions; IV access
- Identify rashes with a potentially life-threatening illness or need for special isolation.
INITIAL STABILIZATION/THERAPY
- Aggressive, empiric management of children with a purpuric rash associated with fever or unstable vital signs:
- Airway support, IV access, fluid resuscitation, pressors if cardiovascular collapse
- IV antibiotics should be administered for suspected etiologies
ED TREATMENT/PROCEDURES
- Specific ED treatment should be directed to the underlying etiology.
- Diphenhydramine should be used when an allergic reaction is suspected.
MEDICATION
- Acetaminophen: 10–15 mg/kg PO/PR q4–6h; do not exceed 5 doses/24 h
- Cefotaxime: 50 mg/kg IV q6h; max. dose, 12 g/24 h
- Ceftriaxone: 50 mg/kg IV q12h; max. dose, 4 g/24 h
- Diphenhydramine: 1.25 mg/kg PO/IM/IV q6h
[Outline]
DISPOSITION
Admission Criteria
- Hospital admission is determined by the underlying disorder.
- Other illnesses associated with systemic illness or potential deterioration, SSS, rubeola, and varicella, as well as others, may require inpatient care.
Discharge Criteria
Discharge instructions should be based on the underlying disorder.
Issues for Referral
- Exanthems associated with self-limited entities in stable children.
- Follow-up with primary care physician or dermatologist should be arranged.
FOLLOW-UP RECOMMENDATIONS
Patient should return for re-evaluation for any rapidly spreading rash, changes in rash morphology, petechiae or hemorrhage, new onset fever or neck stiffness.
[Outline]
- Dermatology atlas: http://www.dermatlas.org/.
- Ely JW, Seabury Stone M. The generalized rash: Part I and part II. Am Fam Physician. 2010;81:726–739.
- Fölster-Holst R, Kreth, HW. Viral exanthems in childhood. Part 1–part 3. J Dtsch Dermatol Ges. 2009;7:309–316, 414–418, 506–510.
- O'Connor NR, McLaughlin MR, Ham, P. Newborn skin: Part I. Common rashes. Am Fam Physician. 2008;77:47–52.
- Stocker JT. Clinical and pathologic differential diagnosis of selected potential bioterrorism agents of interest to pediatric health care providers. Clin Lab Med. 2006;26:329–344.
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