Rash
Basics
Description
Description
- Use appropriate terminology to categorize the unknown rash:
- Basic morphology:
- Diameter
- Flat or elevated
- Solid or fluid filled
- Color:
- Hyperpigmented
- Hypopigmented
- Erythematous
- Shape:
- Discoid
- Oval
- Annular
- Arcuate
- Targetoid
- Distribution:
- Peripheral vs. central
- Symmetrical
- Discrete (separated from one another)
- Linear
- Dermatomal
- Serpiginous
- Reticular
- Grouped
- Photodistributed
- Associated symptoms:
- Itch
- Pain
- Tenderness
- Burning
- Systemic symptoms
- Evolution of the rash:
- Onset and duration
- Severity and flares
- Basic morphology:
- Morphology:
- Vesiculobullous lesions:
- Fluid-filled swelling of the skin or sloughing due to disruption of epidermal/dermal integrity
- Purpura and petechiae:
- Failure of normal vascular integrity/hemostatic mechanisms
- Do not blanch on palpation
- Erythema:
- Erythroderma when covering ≥90% of the skin surface
- Vascular dilatation of the superficial vessels leading to red macular lesions
- Blanches on palpation
- Figurate erythema:
- Erythema classified by its particular annular or arcuate shape
- Papulosquamous:
- Papules and scaly desquamation of the skin
- Lesions may also be red and macular
- Classified into psoriasiform, pityriasiform, lichenoid, annular, and eczematous
- Granulomatous lesions:
- Infiltrated papules and plaques, lack of scales
- “Apple jelly” appearance when pressed with glass slide
- Nodules:
- Secondary to prolonged inflammatory response, cyst, or infiltrative process
- Vesiculobullous lesions:
- Warning signs of a potential emergency condition:
- Erythroderma
- Blistering/desquamation
- Purpura
- Skin pain with systemic symptoms
- Vesiculobullous lesions:
- Toxic epidermal necrolysis (mucosal and >30% body surface area involvement)
- Stevens–Johnson syndrome (mucosal and ≤10% body surface area involvement)
- Pemphigus vulgaris
- Bullous pemphigoid
- Disseminated herpes simplex
- Herpes zoster
- Varicella
- Smallpox
- Vaccinia
- Allergic contact dermatitis
- Purpura and petechiae:
- Meningococcemia
- Gonococcemia
- Purpura fulminans/disseminated intravascular coagulopathy (DIC)
- Rocky Mountain spotted fever (RMSF):
- Pronounced prodrome of fever, headache, myalgia, rash, peripheral moves to palms/soles
- Ecthyma gangrenosum:
- Pseudomonas infections in critically ill and immunocompromised patients
- Babesiosis: Similar to RMSF, rash less often, frequent coinfection with Lyme
- Vasculitis
- Multiple systemic illnesses (see “Purpura”)
- Erythroderma:
- Toxic shock syndrome
- Drug-induced
- Psoriasis
- Seborrheic dermatitis
- Mycosis fungoides
- Lymphoma of the skin
- Erythematous rashes:
- Localized:
- Cellulitis
- Early necrotizing fasciitis with concomitant skin pain
- Urticaria
- Diffuse:
- Staphylococcal scalded skin syndrome
- Toxic shock syndrome
- Drug-induced, including drug reaction with eosinophilia and systemic symptoms (DRESS)
- Viral exanthema
- Allergic reaction from drugs, food, infection, pressure, heat, or cold
- Localized:
- Figurate erythema:
- Erythema chronicum migrans (large red ring that arises around a tick bite):
- Lyme disease
- Erythema multiforme:
- Mycoplasma pneumoniae
- Herpes simplex
- Drug reaction leading to Steven–Johnson syndrome
- Erythema chronicum migrans (large red ring that arises around a tick bite):
- Papulosquamous:
- Psoriasiform:
- Psoriasis
- Seborrheic dermatitis
- Drug-induced
- Pityriasiform:
- Pityriasis rosea
- Secondary syphilis
- Tinea versicolor
- Lichenoid:
- Lichen planus
- Drug-induced
- Annular:
- Tinea
- Figurate erythema (see below)
- Eczematous:
- Atopic dermatitis
- Allergic contact dermatitis
- Irritant dermatitis
- Psoriasiform:
- Nodules:
- Granulomatous disease:
- Sarcoid
- Granuloma annulare
- Infectious: Leprosy, tuberculosis, deep fungal infection
- Panniculitis:
- Erythema nodosum
- Lymphoma of the skin
- Cysts
- Tumors and metastatic disease
- Granulomatous disease:
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Citation
Schaider, Jeffrey J., et al., editors. "Rash." 5-Minute Emergency Consult, 6th ed., Lippincott Williams & Wilkins, 2020. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307138/all/Rash.
Rash. In: Schaider JJJ, Barkin RMR, Hayden SRS, et al, eds. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307138/all/Rash. Accessed October 7, 2024.
Rash. (2020). In Schaider, J. J., Barkin, R. M., Hayden, S. R., Wolfe, R. E., Barkin, A. Z., Shayne, P., & Rosen, P. (Eds.), 5-Minute Emergency Consult (6th ed.). Lippincott Williams & Wilkins. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307138/all/Rash
Rash [Internet]. In: Schaider JJJ, Barkin RMR, Hayden SRS, Wolfe RER, Barkin AZA, Shayne PP, Rosen PP, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. [cited 2024 October 07]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307138/all/Rash.
* Article titles in AMA citation format should be in sentence-case
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ED - Schaider,Jeffrey J,
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ED - Wolfe,Richard E,
BT - 5-Minute Emergency Consult
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PB - Lippincott Williams & Wilkins
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