Allergic Bronchopulmonary Aspergillosis Misdiagnosed as Non-resolving Pneumonia: A Case Report

Abstract

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity reaction triggered by Aspergillus fumigatus colonization of the airways that primarily affects immunocompetent individuals, particularly those with asthma. ABPA can often be misdiagnosed as severe asthma or non-resolving pneumonia, leading to delays in appropriate management. Early recognition of ABPA is crucial to prevent disease progression and unnecessary antibiotic use. We report a case of a 28-year-old female with a long-standing history of poorly controlled asthma who presented with fever, productive cough, and radiographic findings initially suggestive of non-resolving pneumonia. Despite receiving multiple courses of antibiotics, her symptoms persisted. Further investigations, including elevated total serum IgE levels, Aspergillus-specific IgE, eosinophilia, and negative mycobacterial cultures, confirmed a diagnosis of ABPA. The patient was successfully treated with systemic corticosteroids (prednisone) and itraconazole, leading to significant clinical and radiological improvement over 2 months. Her IgE levels markedly decreased, supporting resolution of the hypersensitivity reaction. This case underscores the importance of recognizing ABPA in patients with recurrent asthma exacerbations and unexplained pulmonary symptoms. Given the potential for misdiagnosis as pneumonia, clinicians should maintain a high index of suspicion for ABPA, particularly in cases of non-resolving pneumonia where antibiotic therapy fails to achieve improvement.

INTRODUCTION

Aspergillus are fungi that can cause a spectrum of pulmonary diseases, influenced by the immune status of the host. ABPA occurs in immunocompetent individuals with asthma or atopy and is often misdiagnosed as recurrent pneumonia due to overlapping clinical and radiographic features.[1] ABPA is frequently confused with non-resolving pneumonia, leading to repeated courses of antibiotics without clinical improvement.[2] Early recognition and differentiation are essential, as ABPA is primarily managed with corticosteroids rather than antimicrobial therapy.[3]

Here, we present a case of a young female with a history of uncontrolled asthma who exhibited radiographic findings initially suggestive of non-resolving pneumonia. However, further diagnostic workup confirmed ABPA. This case highlights the importance of considering ABPA in patients who fail to respond to standard pneumonia treatment.

CASE REPORT

A 28-year-old female with a long-standing history of asthma presented with subjective fever and productive cough. Her asthma had been classified as severe due to frequent exacerbations requiring systemic corticosteroids. However, she was not on long-term controller therapy. She developed a productive cough with greenish sputum 4 weeks before admission, which progressed to fever, chills, and malaise. She had been treated with broad-spectrum antibiotics at another facility for presumed pneumonia without improvement. Due to persistent symptoms, pulmonary tuberculosis was suspected but later ruled out.

On examination, the patient was hemodynamically stable without respiratory distress. Chest auscultation revealed diminished breath sounds in the left upper zone and fine crepitations. No wheezing was detected. Laboratory findings showed eosinophilia, elevated inflammatory markers, and significantly elevated total and Aspergillus-specific IgE [Table 1]. A chest CT scan revealed high-attenuation mucus in the left upper lobe with diffuse central bronchiectasis, which is almost pathognomonic for ABPA [Figure 1]. Bronchoscopy with bronchoalveolar lavage confirmed Aspergillus species, while bacterial and mycobacterial cultures were negative. Given the lack of immunosuppression and the presence of elevated IgE levels, a diagnosis of ABPA was made.

Table 1.

Laboratory test results

Parameter	Result	Normal range
White blood cell count (k/μL)	12	4–11
Neutrophils (%)	80.4	40–75
Lymphocytes (%)	10	20–40
Monocytes (%)	6.3	3–9
Eosinophils (%)	11.3	0–6
ESR (mm/h)	119	0–20
Total IgE (kU/L)	2182	5–500
Aspergillus-specific IgE (kU/L)	9.54	≤0.35

ESR – Erythrocyte sedimentation rate; IgE – Immunoglobulin E

Figure 1.

A computed tomography scan of the chest showing high-attenuation mucus impaction

Treatment with prednisone (0.5 mg/kg) and itraconazole (200 mg twice daily) resulted in clinical and radiological improvement over 2 months. Follow-up chest imaging showed resolution of consolidations, though bronchiectasis persisted [Figure 2]. The patient’s IgE levels declined to 324 kU/L, and prednisone was tapered gradually over several weeks. Itraconazole (200 mg twice daily) was continued for 6 months. At the last follow-up, the patient remained clinically stable, with no recurrence of symptoms and sustained improvement on imaging.

Figure 2.

A computed tomography scan of the chest revealing marked improvement with clearing of the hyperattenuating mucus after treatment of allergic bronchopulmonary aspergillosis with systemic corticosteroids and oral itraconazole; however, significant underlying bronchiectasis persisted after treatment

DISCUSSION

ABPA is a hypersensitivity reaction to Aspergillus fumigatus, occurring primarily in asthmatic or cystic fibrosis patients.[4] It is frequently misdiagnosed as non-resolving pneumonia, leading to unnecessary antibiotic therapy.[5] While severe asthma can present with airway remodelling and eosinophilia, the presence of Aspergillus-specific IgE is crucial for distinguishing ABPA.[6]

Radiographically, ABPA can mimic pneumonia, particularly when consolidations and bronchiectasis are present. However, key radiologic features, such as high-attenuation mucus plugging, are pathognomonic for ABPA and should be considered when the patient fails to respond to antibiotic therapy.[7] These findings, along with the clinical presentation, should prompt consideration of ABPA over other differential diagnoses.[8] The presence of high-attenuation mucus, visible on CT scans, helps confirm ABPA even in the absence of other diagnostic criteria, adding significant value to the diagnosis.

Previous studies indicate that asthma is a key risk factor for ABPA, particularly in patients with recurrent exacerbations.[9] Our patient had frequent asthma exacerbations, requiring multiple courses of systemic corticosteroids. Despite this, ABPA was never considered until the current presentation. The delayed diagnosis highlights the need for heightened clinical suspicion in similar cases.

Early identification and treatment of ABPA can prevent disease progression and irreversible bronchiectasis.[10] Our patient responded well to systemic corticosteroids and itraconazole, with clinical and radiographic improvement. Monitoring total IgE levels is essential for assessing treatment response, as demonstrated in this case.[11]

CONCLUSION

Allergic bronchopulmonary aspergillosis should be considered in asthmatic patients presenting with non-resolving pneumonia, persistent pulmonary symptoms, abnormal imaging, and elevated IgE levels. This case emphasizes the importance of recognizing ABPA to avoid unnecessary antibiotic treatment. Clinicians should maintain a high index of suspicion for ABPA in patients with pneumonia-like presentations that fail to respond to conventional therapy. Further research is needed to explore long-term outcomes and emerging therapeutic options for ABPA management.

Declaration of patient consent

The author certifies that she has obtained the appropriate patient consent form. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Ethical considerations

The Institutional Review Board of Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia, provided ethical approval for reporting this case (Ref. no.: IRB-2024-01-916).

Peer review

This case report was peer-reviewed by three independent and anonymous reviewers.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.