Pruritus: Difference between revisions
(Expanded with EM-focused content: dermatologic vs systemic causes, red flags, evaluation strategy, symptomatic management, disposition) |
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===Symptomatic Relief=== | ===Symptomatic Relief=== | ||
* | *Antihistamines: [[diphenhydramine]], [[hydroxyzine]], or non-sedating ([[cetirizine]], [[loratadine]]) | ||
* | *[[Topical steroids]]: for localized inflammatory dermatoses (avoid on face/groin long-term) | ||
* | *Calamine lotion or cool compresses for temporary relief | ||
* | *Oatmeal baths for generalized pruritus | ||
===Condition-Specific=== | ===Condition-Specific=== | ||
* | *[[Urticaria]]: H1 blocker ([[diphenhydramine]] or [[cetirizine]]); add H2 blocker ([[famotidine]]) for refractory; short course [[prednisone]] for severe | ||
* | *[[Scabies]]: permethrin 5% cream (applied neck down, left on 8-14 hours); treat all household contacts simultaneously | ||
* | *[[Contact dermatitis]]: remove exposure, topical steroids, oral steroids for severe/widespread | ||
* | *Uremic pruritus: nephrology consultation, gabapentin may help | ||
*'''Cholestatic pruritus''': cholestyramine, refer for biliary evaluation | *'''Cholestatic pruritus''': cholestyramine, refer for biliary evaluation | ||
Revision as of 09:34, 22 March 2026
Background
- Pruritus (itchiness) is a common ED complaint that may represent a benign dermatologic condition or a systemic disease
- Can be localized or generalized
- Generalized pruritus without rash warrants consideration of systemic causes (renal, hepatic, hematologic, endocrine, malignancy)
- Most common ED presentations are allergic/contact dermatitis, urticaria, drug reactions, and infestations
Clinical Features
History
- Onset, duration, distribution (localized vs. generalized)
- Relationship to exposures: new medications, soaps, detergents, plants, animals, occupational
- Timing: worse at night (scabies, eczema), seasonal (allergic)
- Associated rash: urticarial, vesicular, papular, or no visible skin changes
- Constitutional symptoms: weight loss, night sweats, fatigue (consider malignancy, systemic disease)
- Medical history: liver disease, kidney disease, thyroid disease, diabetes, HIV, lymphoma
Physical Exam
- Excoriations, lichenification (chronic scratching)
- Primary lesion identification: wheals (urticaria), vesicles (contact dermatitis), burrows (scabies), dermatomes (varicella-zoster)
- Distribution pattern may suggest etiology
- Jaundice, hepatomegaly (cholestasis)
- Lymphadenopathy (lymphoma)
- Thyromegaly (hyperthyroidism)
Red Flags
- Generalized pruritus without rash (consider systemic cause)
- Associated with urticaria + dyspnea/hypotension → anaphylaxis
- Unintentional weight loss (malignancy screen)
- Jaundice (biliary obstruction)
- Nighttime pruritus with household contacts affected (scabies)
Differential Diagnosis
Pruritus
Dermatologic/Immunologic Disorders
- Xerosis
- Atopic dermatitis
- Allergic reaction
- Bullous pemphigoid
- Exfoliative erythroderma
- Miliaria (Heat Rash)
- Lichen sclerosus
- Blister chemical agents
Infection, Infection-associated, and Other Critters
- Varicella
- Pityriasis rosea, Erythema infectiosum
- Pruritic papular eruption of HIV
- Candida vulvovaginitis, Candida dermatitis
- Tinea
- Cercarial dermatitis
- Scabies, Lice, Bed bugs
- Herpes simplex
- Condyloma acuminata
- Strongyloides stercoralis, Enterobius, Fasciola hepatica, Loa loa, Dracunculiasis
Systemic Conditions
- Uremia
- Hyperbilirubinemia/cholestasis
- Hepatitis C
- Leukemia, Lymphoma
- Polycythemia vera
- Medication or drug of abuse adverse effect
- Psychiatric/psychogenic
Dermatologic (With Rash)
- Urticaria / allergic reaction
- Contact dermatitis
- Atopic dermatitis (eczema)
- Scabies, pediculosis (lice)
- Varicella-zoster / herpes simplex
- Drug eruptions
- Fungal infections (Tinea, candidiasis)
- Psoriasis
Systemic (Without Primary Rash)
- Chronic kidney disease (uremic pruritus)
- Cholestasis / liver disease
- Hyperthyroidism or hypothyroidism
- Iron deficiency anemia, polycythemia vera
- Lymphoma (Hodgkin's), other malignancy
- HIV
- Pregnancy (intrahepatic cholestasis of pregnancy)
Evaluation
Localized Pruritus with Obvious Dermatologic Cause
- Clinical diagnosis usually sufficient
- No laboratory workup necessary
Generalized Pruritus Without Clear Cause
- CBC with differential (eosinophilia, polycythemia, anemia)
- BMP (renal function — uremia)
- Liver function tests, bilirubin (cholestasis)
- TSH (thyroid disease)
- Glucose (diabetes)
- Consider CXR if concern for lymphoma (mediastinal mass)
- Consider iron studies, HIV testing, hepatitis serologies based on clinical context
Management
General
- Treat underlying condition when identified
- Avoid hot water, harsh soaps, known irritants
- Emollients for dry skin
Symptomatic Relief
- Antihistamines: diphenhydramine, hydroxyzine, or non-sedating (cetirizine, loratadine)
- Topical steroids: for localized inflammatory dermatoses (avoid on face/groin long-term)
- Calamine lotion or cool compresses for temporary relief
- Oatmeal baths for generalized pruritus
Condition-Specific
- Urticaria: H1 blocker (diphenhydramine or cetirizine); add H2 blocker (famotidine) for refractory; short course prednisone for severe
- Scabies: permethrin 5% cream (applied neck down, left on 8-14 hours); treat all household contacts simultaneously
- Contact dermatitis: remove exposure, topical steroids, oral steroids for severe/widespread
- Uremic pruritus: nephrology consultation, gabapentin may help
- Cholestatic pruritus: cholestyramine, refer for biliary evaluation
Disposition
Discharge (Most Patients)
- Most patients with pruritus can be safely discharged
- Outpatient follow-up with primary care or dermatology for persistent or unexplained pruritus
- Return precautions: spreading rash, difficulty breathing, swelling, fever, worsening symptoms
Admit
- Associated anaphylaxis
- Severe drug reaction (consider Stevens-Johnson syndrome, DRESS syndrome)
- Symptomatic systemic disease requiring inpatient workup (new renal failure, obstructive jaundice)