Rosen & Barkin's 5-Minute Emergency Medicine Consult (578 page)

• Lymphoma, including Hodgkin lymphoma
  
• Mycosis fungoides
  
• Leukemia
  
• CNS tumors
  
• Multiple myeloma
  
• Carcinoid
  
• Visceral malignancies (breast, stomach, lung)
  

• Uremia
  
• Hyperthyroidism
  
• Hypothyroidism
  
• Hyperparathyroidism
  
• Diabetes mellitus
  
• Carcinoid
  

• Multiple sclerosis: Paroxysmal itching
  
• Notalgia paraesthetica: Local itch of back, medial shaft scapula
  
• Brain abscess
  
• CNS infarct
  
• Cerebral tumor
  
• Creutzfeldt-Jakob disease
  

• Chronic renal failure
  
• Chronic hemodialysis
  

• Sjögren syndrome
  
• Dermatomyositis
  

• Stress, anxiety, neurotic excoriation
  
• Delusions of parasitosis
  
• Psychogenic pruritus
  

TREATMENT

• Start with antihistamines for pruritus of undetermined etiology
  
• Emollients indicated for dry skin
  
• Coolants to alleviate itching, for neural modulation: Menthol, camphor, eucalyptus oil, calamine lotion, ice, topical anesthetics
  
• Substance P evacuators (capsaicin) block C fibers:
  
  • Burning sensation during 1st weeks of use
    
  • Anesthetic can be applied prior
    
• Topical glucocorticoids for contact dermatitis
  
• Permethrin cream for scabies and lice when rash is suggestive
  
• Topical antihistamines (e.g., doxepin) for eczema, urticaria, bites
  
• Swimmer’s itch:
  
  • Control with antihistamines, cool compresses, calamine lotion
    
  • Topical steroids to suppress intense inflammation
    
  • Towel dry immediately after leaving water as preventive measure
    
• Discontinue medications that may cause allergic reaction
  
• UV light for uremic pruritus
  
• Treat the underlying cause for pruritus associated with a systemic disease
  

• Oral antihistamines:
  
  • Chlorpheniramine 4 mg (peds: 0.35 mg/kg/24h div. q 4–6h PRN; 2–6 yr max. 4 mg/24h; 6–12 yr max. 12 mg/24h) PO q4–6h PRN; max. 24 mg/24h
    
  • Diphenhydramine 25–50 mg (peds: 5 mg/kg/24h div. q6h PRN; 2–5 yr max. 37.5 mg/24h; 6–11 yr max. 150 mg/24h; >12 yr max. 400 mg/24h) PO q4–6h PRN; max. 400 mg/24h
    
  • Hydroxyzine 25–100 mg (peds: 2 mg/kg/24h div. q6h PRN) PO q6–8h PRN; max. 600 mg/24h
    
• Topical treatments:
  
  • Capsaicin 0.025%, 0.075% cream: Apply TID–QID
    
  • Doxepin 5% cream: Apply QID for up to 8 days (to max. of 10% of the body)
    
  • EMLA (2.5% lidocaine + 2.5% prilocaine): Apply prior to capsaicin
    
  • Hydrocortisone 0.5%, 1%, 2.5%: Up to QID
    
  • Permethrin 5% cream (for scabies):
    
    • Apply from neck down after bath
      
    • Wash off thoroughly with water in 8–12 hr
      
    • May repeat in 7 days
      
  • Permethrin 1% cream rinse (for lice):
    
    • Shampoo, rinse, towel dry, saturate hair and scalp (or other affected area), leave on 10 min, then rinse
      
    • May repeat in 7 days
      
  • White petroleum emollients: Apply after short bath/shower in warm (not hot) water
    
• Other treatments for specific diseases
  

FOLLOW-UP

• Anaphylaxis
  
• Generalized exfoliating lesions
  
• Manifestations of systemic diseases requiring admission
  

Vary by etiology

• Refer patients with skin lesions to primary care physician or dermatologist
  
• Stable patients with pruritus without skin lesions should be discharged on antipruritic medication and referred to a physician for an underlying systemic illness
  

• Practical recommendations for dry skin:
  
  • Take baths with baking soda, bath oils, or colloidal oatmeal
    
  • Use moisturizers frequently during day and immediately after bathing
    
• Avoid:
  
  • Dry air (humidity <40%)
    
  • Contact irritants (e.g., wool, cleansers)
    
  • Alkaline soaps and overwashing
    
  • Alcohol, caffeine, peppery foods
    
  • Overexposure to heat, hot water
    

• Detailed history is key in the ED workup
  
• Pruritus can be indicative of systemic illness
  
• No single treatment for all causes of pruritus
  

• Cassano N, Tessari G, Vena GA, et al. Chronic pruritus in the absence of specific skin disease: An update on pathophysiology, diagnosis, and therapy.
  Am J Clin Dermatol
  . 2010;11(6):399–411.
  
• Grundmann S, Stander S. Chronic pruritus: Clinics and treatment.
  Ann Dermatol
  . 2011;23(1):1–11.
  
• Raap U, Stander S, Metz M. Pathophysiology of itch and new treatments.
  Curr Opin Allergy Clin Immunol.
  2011;11(5):420–427.
  
• Steinhoff M, Cevikbas F, Ikoma A, et al. Pruritus: Management algorithms and experimental therapies.
  Semin Cutan Med Surg.
  2011;30(2):127–137.
  
• Tey HL, Yosipovitch G. Targeted treatment of pruritus: A look into the future.
  Br J Dermatol
  . 2011;165(1):5–17.
  

See Also (Topic, Algorithm, Electronic Media Element)

• Anaphylaxis
  
• Anemia
  
• Contact Dermatitis
  
• Eczema/Atopic Dermatitis
  
• Hepatitis
  
• HIV/AIDS
  
• Hyperparathyroidism
  
• Hyperthyroidism
  
• Hypothyroidism
  
• Leukemia
  
• Multiple Myeloma
  
• Multiple Sclerosis
  
• Pediculosis
  
• Polycythemia
  
• Psoriasis
  
• Rash
  
• Renal Failure
  
• Scabies
  
• Seborrheic Dermatitis
  
• Tinea Infections, Cutaneous
  
• Urticaria
  

CODES

• 120.3 Cutaneous schistosomiasis
  
• 693.0 Dermatitis due to drugs and medicines taken internally
  
• 698.8 Other specified pruritic conditions
  

BASICS

• Buildup of CSF pressure without mass lesion or clear etiology
  
• Also known as idiopathic intracranial hypertension
  
• 2 proposed mechanisms:
  
  • Increased abdominal pressure or intracranial venous stenosis may decrease venous drainage from the head
    
  • Vitamin A levels above the saturation of the liver can damage cell membranes in the arachnoid granulations
    
• Associated with obesity
  
• Average age of onset 30 yr
  
• Female predominance (7:1)
  
• Uncommon, ∼1–5 cases per 100,000
  

Proposed causative agents:

• Obesity
  
• Obstruction of intracranial venous drainage
  
• Hypervitaminosis A
  
• Steroids/steroid withdrawal
  
• Tetracycline antibiotics
  
• Oral contraceptive pills
  
• Hypertension
  
• Recent weight gain
  
• Chronic carbon dioxide retention with elevated intracranial pressure
  

DIAGNOSIS