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General approach to rashes
From WikEM
(Redirected from Rash)
This page is for adult patients; for other age groups see pediatric rashes and neonatal rashes
Contents
Background
- A wide range of benign and dangerous pathology can present with a rash
Rash Red Flags[1]
- Fever
- Toxic appearance
- Hypotension
- Mucosal lesions
- Severe pain
- Very old or young age
- Immunosuppressed
- New medication
Dermatology Nomenclature
Small lesions (<0.5cm)
- Macule – flat, cirumscribed, colored, non palpable
- Papule – raised, solid and palpable
- Vesicle – raised, palpable, clear fluid-filled
- Pustule – raised, palpable, pus filled (leukocytes or keratin)
Large lesions (>0.5cm)
- Patch – large macule (flat non-palpable colored area)
- Plaque – superficially raised, circumscribed solid area
- Nodule – distinct large papule
- Bulla - large vesicle (blisters if epidermal layer completely sloughed off)
- Wheal – firm and edematous plaque (edema of the dermis)
Other
- Plaque/scaley papule
- Eschar
- Erosion/ulcer
- Purpura/petechia
- Plaque/smooth papule
Clinical Features
History
- Key elements from the history include:
- Distribution and progression of the skin lesions
- Recent exposures (sick contacts, foreign travel, sexual history and vaccination status)
- Any new medications
Physical Exam
- Pay specific attention to vital signs
- A rash associated with fever or hypotension should make you worry about potentially deadly diagnoses
- Perform a careful physical exam
- Undressing the patient to fully examine the trunk and the extremities
- Look at palms, soles and mucous membranes
- Touch the skin with a gloved hand to determine if the lesions are flat or raised
- Press on lesions to see whether they blanch
- Rub erythematous skin to see if it sloughs
Differential Diagnosis
Rash
- Acute generalized exanthematous pustulosis
- Allergic reaction
- Aphthous stomatitis
- Atopic dermatitis
- Cellulitis
- Chickenpox
- Chikungunya
- Coxsackie
- Dermatitis herpetiformis
- Drug rash
- DRESS syndrome
- Erysipelas
- Erythema multiforme
- Exfoliative erythroderma
- Henoch-schonlein purpura
- Hives
- Impetigo
- Measles
- Miliaria (Heat Rash)
- Necrotizing fasciitis
- Pellagra
- Petechiae & Purpura
- Poison Oak, Ivy, Sumac
- Psoriasis
- Pityriasis rosea
- Scabies
- Seborrheic dermatitis
- Serum Sickness
- Smallpox
- Shingles
- Stevens-Johnson syndrome and toxic epidermal necrolysis
- Tinea capitus
- Tinea corporis
- Vitiligo
Vesiculobullous rashes
Febrile
- Diffuse distribution
- Varicella
- Smallpox
- Disseminated gonococcal disease
- DIC
- Purpural fulminans
- Localized distribution
Afebrile
- Diffuse distribution
- Bullous pemphigoid
- Drug-Induced bullous disorders
- Pemphigus vulgaris
- Phytophotodermatitis
- Erythema multiforme major
- Localized distribution
Necrotizing rashes
Petechiae/Purpura (by cause)
- Abnormal platelet count and/or coagulation
- Septicemia
- Idiopathic thrombocytopenic purpura (ITP)
- Hemolytic uremic syndrome
- Leukemia
- Coagulopathies (e.g. hemophilia)
- Henoch-Schonlein Purpura (HSP)
- Acute hemorrhagic edema of infancy (AHEI)
- Hypersensitivity vasculitis
- Primary vasculitides
- Wegener's
- Microscopic polyangiitis
- Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)
- Secondary vasculitides
- Connective tissue disorder
- Scurvy
- Infectious disease
- Hepatitis B
- Hepatitis C
- Trauma
Erythematous rash
- Positive Nikolsky’s sign
- Febrile
- Staphylococcal scalded skin syndrome (children)
- Toxic epidermal necrolysis (adults)
- Afebrile
- Febrile
- Negative Nikolsky’s sign
Evaluation
Rash visual diagnosis
Poison ivy/Oak/Sumac
Poison ivy/Oak/Sumac
Psoriasis before and after treatment.
Vesiculobullous rashes visual diagnosis
Management
Disposition
See Also
- Fever and Rash
- Pediatric Rashes
- Visual diagnosis (main)
- Ulcerative STDs
- Dermatologic nomenclature
- Pigmented rashes
- Rashes of pregnancy
External Links
References
- ↑ Nguyen T and Freedman J. Dermatologic Emergencies: Diagnosing and Managing Life-Threatening Rashes. Emergency Medicine Practice. September 2002 volume 4 no 9.
