Overview: Urticaria

• Urticaria, also known as hives, is a common problem affecting approximately 20% of the general population at some point in their lives.

• It is characterized by wheals—discrete areas of swelling, erythema, and pruritus that are often surrounded by a pale halo.

• Individual lesions typically come and go over the course of 24 hours, but recurrent crops can appear for weeks.

• Acute urticaria refers to outbreaks of wheals occurring on at least 2days a week for up to 6 consecutive weeks.

• When the process lasts for 6 weeks or longer, it is considered chronic urticaria.

• Patients who have less frequent outbreaks are classified as having recurrent urticaria.

• The skin findings and symptoms of urticaria are the result of increases in inflammatory and vasoactive mediators such as histamine, prostaglandins, leukotrienes, proteases, and cytokines.

• These mediators are primarily found in mast cells and basophils.

• Although the main physiologic event is mast cell degranulation, any mechanism that elevates these mediators can result in urticaria.

Causative Factors

• Determining the causative factor in a case of urticaria is often very frustrating.

• No specific origin is ever determined in 50% to 80% of patients.

• The most commonly implicated causes of acute urticaria are infections (especially viral infections of the upper respiratory tract), drugs (such as penicillins, sulfonamides, salicylates, nonsteroidal antiinflammatory drugs, and opiates), and foods (particularly shellfish, fish, eggs, cheese, chocolate, nuts, berries, and tomatoes).

• Chronic urticaria can be caused by these same agents but is more likely to be secondary to physical stimuli (e.g., dermatographism, pressure, vibration, heat, cold, exercise, sun, water), stress, autoimmune diseases (most commonly thyroid disorders), and other chronic medical diseases, such as connective tissue disease, cryoglobulinemia or cryofibrinogenemia, rheumatoid arthritis, amyloidosis, and onco-diseases.

Important Points to Consider

• Quercetin works by stabilizing mast cells, and butterbur inhibits histamine and leukotrienes. These botanicals may work synergistically on the allergic type of reaction seen in urticaria.

• To prepare sarsaparilla tea, simmer 1 to 4 g of dried sarsaparilla in 8 to 12 oz of water for 5 to 10 minutes.

• The tricyclic antidepressant doxepin has potent antihistamine properties that make it useful for patients with chronic urticaria.

• Hypnosis is a therapy that should be encouraged for chronic urticaria. The evidence is promising, and potential for side effects is minimal.

Menthol-Containing Products for Topical Use

• Aveeno Skin Relief Moisturizing Lotion: menthol and colloidal oatmeal

• Sarna Anti-Itch Lotion: 0.5% menthol and 0.5% calamine

• Gold Bond Medicated Body Lotion: 0.15% menthol (Extra Strength has 0.5% menthol)

• PrameGel: 0.5% menthol and 1% pramoxine

• Watkins Menthol Camphor Ointment: 2.8% menthol and 5.3% camphor

• Eucerin Itch-Relief Spray: 0.15% menthol

  
  

Prevention Prescription

If a cause is identified in a particular patient, recurrences can be limited by having the patient

• Avoid exposure to known triggers.

• Limit stress.

• Eat a healthy, balanced diet with a low histamine content.

Therapeutic Review: Herpes Simplex Virus

This is a summary of therapeutic options for urticaria. Laboratory investigation should be directed by the history and physical findings. Particular attention to associations with systemic disease is warranted in patients with chronic urticaria.

General Measures

• Identify and avoid any precipitating factors, if possible. Activity and ingestant diaries may be particularly useful in this endeavor.

• Use topical measures, including a cool, calm environment, loosely fitting, comfortable clothes, baths with cornstarch, colloidal oatmeal (Aveeno), or baking powder.

Nutrition

• Avoid allergenic foods and foods high in histamine (see Table 70-1).

• Consider an elimination diet (Food Intolerance and Elimination Diet)

  
  

Botanicals and Supplements

• Quercetin: 400 mg orally twice daily before meals

• Butterbur (Petadolex): 75 mg orally twice daily

• Sarsaparilla: 1 to 4 g as dried root or tea three times daily; liquid extract (1:1 in 20% alcohol or 10% glycerol): 8 to 15 mL three times daily

• Stinging nettle: 300 mg three times daily

• Peppermint: 0.2 to 0.4 mL oil three times daily between meals or equivalent in enteric-coated tablets

• Ginkgo biloba for cold-induced urticaria: 120 mg/day standardized extract

• Valerian root for stress-related urticaria: 200 to 300 mg/day

  
  

Pharmaceuticals

• Antihistamines: H1-receptor blockers alone or in combination with H -receptor blockers

• First Generation

  • Hydroxyzine: 50 mg one to four times daily

  • Diphenhydramine: 25 to 50 mg every 6 to 8 hours

  • Chlorpheniramine: 4 to 8 mg twice daily.

  • Promethazine: 12.5 to 25 mg every 6 to 8 hours

  • Second-generation Loratadine (Claritin): 10 mg once or twice daily

  • Fexofenadine (Allegra): 60 to 180 mg once or twice daily

  • Cetirizine (Zyrtec): 10 mg once or twice daily

• H2-receptor antagonists

  • Famotidine (Pepcid): 20 to 40 mg one to twice daily

  • Cimetidine (Tagamet): 200 to 400 mg one to four times daily

  • Doxepin: 10 to 75 mg before bed

• Leukotriene inhibitors

  • Zafirlukast (Accolate): 20 mg twice daily

  • Montelukast (Singulair): 10 mg daily

  • Zileuton (Zyflo): 600 mg up to four times daily

• Corticosteroids: 60 mg/day for 2 to 3 days, then tapered over 1 to 2 weeks

• Cyclosporine: 3 mg/kg/day for 6 weeks, 2 mg/kg/ day for 3 weeks, and 1 mg/kg/day for 3 weeks. Appropriate monitoring is essential

Mind Body Therapy

• Relaxation: Good for everyone.

• Hypnosis, especially for people classified as hypnotizable

Traditional Chinese Medicine

• Refer to text: Dermatology in Traditional Chinese Medicine, by Xu Yihou

Key Web Sources

• American Academy of Dermatology: http://www.aad.org/public/publications/pamphlets/skin_urticaria.html

• Mayo Clinic: http://www.mayoclinic.com/health/chronic-hives/ DS00980

• National Certification Commission for Acupuncture and Oriental Medicine: www.nccaom.org
  American Academy of Medical Acupuncture: www.medicalacu-puncture.org