according to global initiative for asthma ( gina ) guideline , patient who do not reach an acceptable level of control with highest possible step four treatment , i.e. , high dose inhaled corticosteroids ( ics ) , inhaled long acting beta2 agonist ( laba ) , montelukast , and oral sustained release theophylline , can be considered to have difficult - to - treat asthma . incorrect diagnosis , non - compliance and incorrect technique of inhalation are most common causes for persistent uncontrolled asthma classical presentation makes the diagnosis of abpa easy , but atypical clinicoradiological presentation makes the confusion . the prevalence of abpa in an asthmatic population is probably between 1 - 2% and as high as 14% in corticosteroid dependent asthma . a 28-year - old nonsmoker , male office worker , presented with persistent cough with scanty , mucoid expectoration and gradually progressive breathlessness for last two years . past history revealed that since childhood he was suffering from recurrent cough and cold , nasal itching , and obstruction , especially in summer . therefore , the patient was diagnosed as having asthma and medium dose ics plus inhaled laba was advised . despite adequate compliance and correct inhaler technique , his asthma was uncontrolled ; inhaled salbutamol was taken more than twice a week . on general survey at presentation , only mild pallor was seen . his respiratory rate was 24 breaths / minute , and pulse rate 120 beats / minutes . there were bilateral hyperresonant percussion note , diminished vesicular breath sound , and bilateral crackles with occasional wheezing . chest x - ray ( cxr ) , posteroanterior view showed bilateral hyperinflated lung with reticular shadows . spirometry in our institution showed mixed pattern with partial reversibility to inhaled salbutamol , although his effort was not adequate . the patient was advised high dose ics , inhaled laba , and once daily 10 mg montelukast , and the treatment was gradually stepped up by addition once daily 400 mg sustained release theophylline within two months , as his symptoms were not under control . we also advised once daily 40 mg esomeprazole and 30 mg sustained release domperidone , and once daily mometasone nasal spray ( two sprays in each nostril ) . high resolution computed tomogram ( hrct ) of thorax revealed bilateral reticulonodular pattern with patchy consolodation [ figure 1 ] . further investigations showed total serum immunoglobulin e ( ige ) level was 1979.1 u / l and aspergillus fumigatus specific serum ige was positive ( 1.39 u / l ) . the diagnosis of abpa was suggested , although diagnosis was confused with diffuse parenchymal lung disease ( dpld ) due to atypical presentation and hrct pattern . oral prednisolone at dose of 0.5 mg / kg / day along with oral itraconazole 200 mg twice daily was added . oral prednisolone after six weeks was tapered off at the rate of 5 mg / week over six weeks . itraconazole was continued as 200 mg twice daily for eight weeks , then 200 mg once daily for another eight weeks . on six month first confirmation of the diagnosis of asthma , then identification of the cause of the persisting symptoms , assessment of adherence with therapy and technique of inhalation therapy should be done . lastly physician should search for alternative etiology of asthma like symptoms , and definitely abpa is an important differential diagnosis for difficult - to - treat asthma . because of this hypersensitivity , eosinophilic infiltration of the lung parenchyma , bronchial wall and mucus plugging of the bronchi occur , which manifest as eosinophilic pneumonia , bronchiectasis , asthma like symptoms and subsequent fibrosis . aspergillus after entering the airway releases gliotoxin , which causes epithelial damage and cilliary dysfunction . after that , it colonizes within the airways by adhering with fibronectin of extracellular matrix . type i response leads to increased level of non - specific and aspergillus specific ige . type iii reaction results in high level of both total and aspergillus specific igg and iga . there are eight major criteria like asthma , fleeting pneumonia , positive aspergillin skin test , eosinophilia , precipitin antibodies in serum , serum ige level > 1000 mg / ml , central bronchiectasis on hrct thorax , presence of aspergillus fumigates specific igg and ige antibodies in serum , and three minor criteria like presence of aspergillus hyphae in sputum , expectoration of black mucus plug , and delayed skin reaction to aspergillus antigen for the diagnosis of abpa . these criteria may not be evident during remission or in fibrotic stage . abpa is divided into five stages , stage i - acute , stage ii - remission , stage iii - exacerbation , stage iv - corticosteroid dependent asthma , stage v- fibrotic end stage disease . important hrct findings are fleeting pneumonia in upper lobe , central bronchiectasis , and endobronchial mucus plugging . acute exacerbation of abpa can be treated with oral prednisolone , and itraconazole along with step 4 management of gina guideline . oral prednisolone may be continued till good clinical response , radiological clearing of the shadows and a significant fall in the ige level is achieved . classical presentation of abpa in difficult - to - treat asthma makes its diagnosis easy . in our case , due to irregular therapy , classical symptoms of asthma were altered and an irreversible component of airway obstruction was developed . classical hrct features of abpa like fleeting pneumonia , and central bronchiectasis were absent in our case , whereas bilateral reticulonodular shadows confused us with the diagnosis of dpld . but , persistent peripheral blood eosinophilia gave the initial clue for the diagnosis of abpa , which was confirmed by high level of total and aspergillus specific ige , positive aspergillin skin test , and eosinophil predominance on bal fluid study . therefore , the dose of steroid should not be increased inadvertently , rather should search for the abpa in case of difficult - to - treat asthma , if compliance and correct inhaler technique are ensured .