All are features of allergic bronchopulmonary aspergillosis except:
**Question:** All are features of allergic bronchopulmonary aspergillosis except:
A. Aspergillus fumigatus infection
B. Fungal spores in sputum
C. Eosinophilia in blood
D. Asthma exacerbation
**Core Concept:**
Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity disorder caused by Aspergillus fumigatus infection, which can lead to asthma exacerbation, eosinophilia in blood, and presence of fungal spores in sputum. The condition is characterized by an exaggerated immune response to A. fumigatus, leading to a range of clinical features.
**Why the Correct Answer is Right:**
Option D, "Asthma exacerbation," is not a unique feature of ABPA. While ABPA can exacerbate asthma, asthma exacerbation can also occur in other conditions like asthma due to viral infection, air pollution, exposure to irritants, and drug reactions. Thus, asthma exacerbation is not specific to ABPA.
**Why Each Wrong Option is Incorrect:**
Option A, "Aspergillus fumigatus infection," is incorrect because ABPA is a hypersensitivity disorder caused by Aspergillus fumigatus infection. This option is a part of the condition itself, not a feature that does not occur in ABPA.
Option B, "Absence of eosinophilia in blood," is incorrect because eosinophilia is a common feature of ABPA. The condition is characterized by an increased count of eosinophils in the bloodstream, which reflects the heightened immune response to Aspergillus fumigatus.
Option C, "Absence of fungal spores in sputum," is incorrect because the presence of Aspergillus fumigatus spores in sputum is a common feature of ABPA. The detection of spores in sputum is supportive evidence of ABPA diagnosis, as it demonstrates the presence of the causative agent.
**Clinical Pearl:**
ABPA is a complex, chronic inflammatory disorder resulting from an exaggerated immune response to Aspergillus fumigatus infection, leading to a range of clinical features such as asthma exacerbation, eosinophilia, and detection of Aspergillus fumigatus spores in sputum. Understanding these core features helps in distinguishing ABPA from other asthma exacerbations and establishing a correct diagnosis.