II. Epidemiology
- Much more common in adults than children
- Onset age over 40 years old
III. Pathophysiology
- Non-IgE, Non-allergic Asthma
- Neutrophil mediated Asthma
IV. Types: Phenotypes
- Neutrophilic Asthma (adult onset, non-atopic)
- May be paucigranulocytic or Neutrophilic
- Biomarkers include NLRP3/IL-1b and Th17, MMP-9
-
Obesity Associated (esp. female)
- Mediators include oxidative stress, Neutrophil activity, activation of Innate Immunity
- Biomarkers include Serum IL-6
- Associated with severe symptoms despite preserved lung function
- Smoking Associated
- Typically occurs in older adults, with frequent exacerbations and reduced lung function testing
- Differentiate from COPD (or both may be present)
- Induced Sputum with increased Neutrophils (see labs below)
- Mediators include oxidative stress as well as mixed Th2 high and Th2 low activity
- Very Late Onset Asthma (age >50 or >65 years)
- Often steroid resistant
- Induced Sputum with increased Neutrophils (see labs below)
- Mediators include immunosenescence and Th1/Th7 inflammation
V. Risk Factors
- Irritant exposure (esp. Tobacco Smoking)
- Air Pollution
- Fumes
- Perfumes
- Household cleaning agents
- Insecticides
- Fresh paint
- Tobacco Smoking or Secondhand Smoke
- Cold air
- Infection
- Gastroesophageal Reflux
- Medications
- Beta Blockers (even Intraocular Beta Blocker)
- Body Habitus
VI. Findings: Symptoms and Signs
VII. Labs: Markers
-
Neutrophilia
- Sputum Neutrophils >40 to 60%
-
Cytokines (experimental)
- Interleukins (IL-6, IL-8, IL-17)
- Adipokine (Obesity)
VIII. Management
- See Asthma Management
- See Asthma Exacerbation