# Asthma Pathology

> Asthma pathology for NEET-PG Pathology: TH2 inflammation, Curschmann spirals, Charcot-Leyden crystals, airway remodelling and triggers.

- Canonical URL: https://prepelephant.com/topics/neet-pg/pathology/asthma-pathology
- Exam / course: NEET-PG · Subject: Pathology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Asthma Pathology", PrepElephant, https://prepelephant.com/topics/neet-pg/pathology/asthma-pathology

## Direct answer

Asthma is a chronic inflammatory airway disease with variable, reversible airflow obstruction and hyper-reactivity, driven by TH2 lymphocytes, IgE and eosinophils in the allergic (atopic) form. The asthmatic airway shows oedema, smooth muscle hypertrophy, goblet cell hyperplasia with tenacious mucus plugs, a thickened subepithelial basement membrane and an eosinophil-rich infiltrate; sputum contains Curschmann spirals (twisted mucus casts) and Charcot-Leyden crystals from eosinophil granule proteins. Attacks are triggered by allergens, infections, exercise, cold air, aspirin and occupational agents, and status asthmaticus — unremitting attack — can be fatal.

## What you must remember

- **Immunology:** sensitisation produces IgE via TH2-derived interleukin-4, eosinophil recruitment via interleukin-5 and mucus secretion via interleukin-13; mast-cell mediators cause early-phase bronchospasm, and late-phase cellular inflammation sustains it.
- **Atopic (extrinsic) versus non-atopic (intrinsic):** childhood allergic asthma with family history versus adult-onset disease, often triggered by respiratory infections or drugs; aspirin-sensitive asthma completes the Samter triad with nasal polyposis.
- **Mucus plugging:** overstuffed goblet cells and mucous glands fill airways with viscid plugs that contain shed epithelial clusters (Creola bodies) and branching mucus casts.
- **Charcot-Leyden crystals:** bipyramidal crystals of eosinophil granule protein in sputum; Curschmann spirals are twisted mucous casts of small airways — both classic sputum findings.
- **Remodelling:** subepithelial fibrosis producing a thickened basement membrane, smooth muscle hypertrophy and angiogenesis, explaining fixed obstruction in long-standing disease.
- **Fatal asthma pathology:** lungs overinflated with small dark airways plugged by mucus, accompanied by eosinophils and hypertrophied smooth muscle; death is from asphyxia.
- **Management direction:** inhaled corticosteroids as controller therapy with bronchodilators and stepwise escalation per current guidance, plus trigger avoidance; biological agents target severe allergic and eosinophilic disease.

## Common confusion

Asthma is separated from COPD by complete reversibility, diurnal variability, eosinophilic inflammation and onset in youth — yet the two coexist as asthma-COPD overlap. Within asthma, the early phase (minutes, mast-cell mediators, bronchodilator-responsive) differs from the late phase (hours, TH2-cell driven, steroid-responsive). Do not confuse Charcot-Leyden crystals (eosinophil protein, bipyramidal) with Curschmann spirals (mucus casts, spiral shaped); naming the right structure in sputum is a recurring one-mark decision.

## Exam-focused takeaway

Stems show a child with wheeze after dust exposure and a strong family history (atopic asthma), an adult with polyps and aspirin sensitivity, or a sputum photograph with spiral casts. Questions test the interleukin-TH2 axis, the histological triad of mucus, smooth muscle and basement-membrane thickening, and the sputum crystals. Link each microscopic finding to its mechanism and management responds to phase — bronchodilator early, steroid late.

## Frequently asked questions

### Which cells dominate asthmatic airway inflammation?

TH2 lymphocytes orchestrating eosinophils and mast cells through interleukins 4, 5 and 13 in allergic disease.

### What are Curschmann spirals and Charcot-Leyden crystals?

Twisted mucous casts of small airways and bipyramidal crystals of eosinophil granule protein respectively, both found in asthmatic sputum.

### Why is the basement membrane thickened in asthma?

Subepithelial fibrosis from chronic inflammation deposits collagen beneath the epithelium — a key feature of airway remodelling that contributes to fixed obstruction.

### What is the Samter triad?

Asthma, chronic rhinosinusitis with nasal polyps and aspirin sensitivity, due to abnormal arachidonic acid metabolism.

### What is status asthmaticus?

A severe, prolonged attack unresponsive to standard therapy, risking exhaustion, hypercapnia and death from asphyxia.