Exophiala is a common melanized environmental mold with a worldwide distribution. It is usually found in organic waste-enriched soil and decaying plants [1], but has also been isolated from saunas and dishwashers [2] [3]. Exophiala species are increasingly identified as the cause of human infection, typically causing cutaneous infections in immunocompromised hosts [4] [5]. It only rarely presents as isolated pneumonia, with the first published case in 1989 by Barenfanger et al. [6]. Since that time, only 10 cases of isolated Exophiala pulmonary infections have been identified [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]. Of these cases, none manifested as an eosinophilic pneumonia. We presented a case of an immunocompetent patient with an eosinophilic pneumonia caused by an Exophiala species.

A 72-year-old male Arizona resident with moderate-severe chronic obstructive pulmonary disease, type 2 diabetes mellitus, and a 20-pack-year history of smoking presented with a three-week history of cough and fatigue. He was initially treated as an outpatient with a five-day course of steroids, with some temporary symptomatic improvement, followed by profound fatigue. On examination, heart rate was 107bpm, and oxygen saturation 97% on room air. He had no palpable adenopathy, no rash, but had crackles posteriorly in the right mid-lung field. Blood workup was notable for a white blood cell count of 9.7x10⁹/L (4.2–10.2x10⁹/L) with the differential showing neutrophils 8.14x10⁹, lymphocytes 0.40x10⁹, monocytes 0.76x10⁹, eosinophils 0.40x10⁹ and basophils 0.01x10⁹. Serum sodium was 119 mmol/L (135–145 mmol/L). A posteroanterior and lateral chest radiograph (Figure 1) demonstrated a new dense consolidation within the right middle lobe. A subsequent computed tomography scan of the chest (Figure 2) showed diffuse consolidation filling most of the right middle lobe, with associated lymphadenopathy. Initially, he was treated with empiric piperacillin/tazobactam and levofloxacin and a bronchoscopy was performed. The bronchoalveolar lavage revealed a differential of 33% eosinophils, 33% lymphocytes, 11% alveolar macrophages and 18% polymorphonuclear leukocytes, consistent with an eosinophilic pneumonia. All other testing for microorganisms, including coccidioidomycosis was negative. Given no definitive etiology of his progressing pulmonary process, he was treated with corticosteroids and fluconazole 400 mg daily for presumed coccidioidomycosis. Following hospital discharge, the bronchoalveolar lavage fluid culture grew 1+ Exophiala species. Fluconazole was continued and three weeks later, the patient was clinically improving. A follow-up CT scan (Figure 3) showed marked improvement of the consolidation and a new thick-walled cavity in the medial right middle lobe. Coccidioidomycosis complement fixation and immunodiffusion serologies were repeated twice and remained negative. The prednisone was tapered off and he continued fluconazole for a total of 10 weeks. The patient was seen again two months later and after being off treatment for three weeks, was relatively asymptomatic. A repeat computed tomography scan of chest (Figure 4) showed continued improvement of the mass-like consolidation within the medial segment of the right middle lobe. The lesion had lost its cavitary component and had decreased in size.

Exophiala species are uncommon pathogens, but have been noted to have an increasing incidence in immunocompromised patients [16]. The most common site of infection is the skin, but Exophiala species have also been reported to cause sinus, pulmonary, and disseminated disease [17]. Cases of Exophiala pneumonia remain rare, and are usually associated with underlying cystic fibrosis or immunocompromised state. It is well established that up to 19% of patients with cystic fibrosis are colonized with Exophiala species, yet only a few cases of Exophiala species pneumonia have been reported in this group [11] [18]. Our patient did not have either of these two major risk factors; however, he did have moderate obstructive lung disease, yet he developed invasive disease. Given the rarity of pneumonia caused by Exophiala species, a standardized treatment regimen has not been established. Although multiple antifungals have been used to treat pulmonary Exophiala infections, including amphotericin B, ketoconazole, itraconazole, flucytosine and voriconazole, no agent has been shown to be superior to the others [7] [12] [13]. There is no consensus regarding optimal duration of therapy, but most studies suggest between 3–7 months [7] [12] [13].

Acute eosinophilic pneumonia is a rare disorder characterized by abnormal pulmonary imaging, and bronchoalveolar lavage with greater than 25% eosinophils [19]. Typically patients present with nonproductive cough, dyspnea, and fever, but may also have malaise, myalgias, night sweats, and pleuritic chest pain [20]. On physical examination, high fever, tachypnea, and bibasilar inspiratory crackles are common [20]. Treatment is typically systemic glucocorticoid therapy in conjunction with supportive care. Optimal dosing or length is not established, but intravenous methylprednisolone is used for severe hypoxemia or respiratory failure until respiratory failure resolves. Oral prednisone is preferred for patients without respiratory failure or once it has resolved. It is recommended to continue glucocorticoids for two weeks after resolution [20]. There is an extensive list of causes of eosinophilic pneumonia, including helminth infections, non-helminthic infections, medications, toxins, idiopathic acute eosinophilic pneumonia and eosinophilic granulomatosis with polyangiitis. Of the non-helminthic infections, coccidioidomycosis has been established as a cause in several cases [21] and rarely with tuberculosis [22]. Although there was only light growth of Exophiala, no other organism was identified as a source to explain the cavitary lesion. Repeat coccidioidomycosis serologies were negative twice supporting our diagnosis of Exophiala pneumonia presenting as an eosinophilic pneumonia. In follow-up with the patient, he remembered that six weeks prior to his hospitalization, he had been digging and laying a ground sterilizer in his yard. He remembered the wind blowing quite briskly and that dirt and the sterilizer frequently blew in his face. He was not wearing a mask at the time.

Exophiala pneumonia remains rare and is usually associated with underlying bronchiectasis, such as cystic fibrosis or with an immunocompromised state. Eosinophilic pneumonia is also a rare disorder that has been associated with non-helminthic infections such as coccidioidomycosis and tuberculosis in addition to certain medications and chemical exposure. Our patient likely developed the Exophiala pneumonia with an eosinophilic pneumonia syndrome due to the inhalation of dust and ground sterilizer. Our case emphasizes the importance of clinical history especially in an unusual pneumonia in an immunocompetent patient.

1. de Hoog GS, Hermanides-Nijhof EJ. The black yeasts and allied hyphomycetes (studies in mycology). Baarn, The Netherlands: Centraalbureau voor Schimmelcultures; 1977.    
2. Matos T, de Hoog GS, de Boer AG, de Crom I, Haase G. High prevalence of the neurotrope Exophiala dermatitidis and related oligotrophic black yeasts in sauna facilities. Mycoses 2002 Nov;45(9-10):373–7.   [CrossRef]   [Pubmed]    
3. Zalar P, Novak M, de Hoog GS, Gunde-Cimerman N. Dishwashers–a man-made ecological niche accommodating human opportunistic fungal pathogens. Fungal Biol 2011 Oct;115(10):997–1007.   [CrossRef]   [Pubmed]    
4. Clancy CJ, Wingard JR, Hong Nguyen M. Subcutaneous phaeohyphomycosis in transplant recipients: Review of the literature and demonstration of in vitro synergy between antifungal agents. Med Mycol 2000 Apr;38(2):169–75.   [CrossRef]   [Pubmed]    
5. Hague J, Liotta E. Subcutaneous phaeohyphomycosis caused by Exophiala jeanselmei in an immunocompromised host. Cutis 2003 Aug;72(2):132–4.   [Pubmed]    
6. Barenfanger J, Ramirez F, Tewari RP, Eagleton L. Pulmonary phaeohyphomycosis in a patient with hemoptysis. Chest 1989 May;95(5):1158–60.   [CrossRef]   [Pubmed]    
7. Bulloch MN. The treatment of pulmonary Wangiella dermatitidis infection with oral voriconazole. J Clin Pharm Ther 2011 Jun;36(3):433–6.   [CrossRef]   [Pubmed]    
8. Diemert D, Kunimoto D, Sand C, Rennie R. Sputum isolation of Wangiella dermatitidis in patients with cystic fibrosis. Scand J Infect Dis 2001;33(10):777–9.   [CrossRef]   [Pubmed]    
9. Diemert D, Kunimoto D, Sand C, Rennie R. Sputum isolation of Wangiella dermatitidis in patients with cystic fibrosis. Scand J Infect Dis 2001;33(10):777–9.   [CrossRef]   [Pubmed]    
10. Haase G, Skopnik H, Kusenbach G. Exophiala dermatitidis infection in cystic fibrosis. Lancet 1990 Jul 21;336(8708):188–9.   [CrossRef]   [Pubmed]    
11. Kusenbach G, Skopnik H, Haase G, Friedrichs F, Döhmen H. Exophiala dermatitidis pneumonia in cystic fibrosis. Eur J Pediatr 1992 May;151(5):344–6.   [CrossRef]   [Pubmed]    
12. Manian FA, Brischetto MJ. Pulmonary infection due to Exophiala jeanselmei: successful treatment with ketoconazole. Clin Infect Dis 1993 Mar;16(3):445–6.   [CrossRef]   [Pubmed]    
13. Mukai Y, Nureki S, Hata M, et al. Exophiala dermatitidis pneumonia successfully treated with long-term itraconazole therapy. J Infect Chemother 2014 Jul;20(7):446–9.   [CrossRef]   [Pubmed]    
14. Mukaino T, Koga T, Oshita Y, Narita Y, Obata S, Aizawa H. Exophiala dermatitidis infection in non-cystic fibrosis bronchiectasis. Respir Med 2006 Nov;100(11):2069–71.   [CrossRef]   [Pubmed]    
15. Suzuki K, Nakamura A, Fujieda A, Nakase K, Katayama N. Pulmonary infection caused by Exophiala dermatitidis in a patient with multiple myeloma: A case report and a review of the literature. Med Mycol Case Rep 2012 Oct 17;1(1):95–8.   [CrossRef]   [Pubmed]    
16. Ben-Ami R, Lewis RE, Raad II, Kontoyiannis DP. Phaeohyphomycosis in a tertiary care cancer center. Clin Infect Dis 2009 Apr 15;48(8):1033–41.   [CrossRef]   [Pubmed]    
17. McCarty TP, Baddley JW, Walsh T, et al. Phaeohyphomycosis in transplant recipients: Results from the Transplant Associated Infection Surveillance Network (TRANSNET). Med Mycol 2015 Jun;53(5):440–6.   [CrossRef]   [Pubmed]    
18. Horré R, Schaal KP, Siekmeier R, Sterzik B, de Hoog GS, Schnitzler N. Isolation of fungi, especially Exophiala dermatitidis, in patients suffering from cystic fibrosis. A prospective study. Respiration 2004 Jul-Aug;71(4):360–6.   [CrossRef]   [Pubmed]    
19. Umeki S. Reevaluation of eosinophilic pneumonia and its diagnostic criteria. Arch Intern Med 1992 Sep;152(9):1913–9.   [Pubmed]    
20. Rhee CK, Min KH, Yim NY, et al. Clinical characteristics and corticosteroid treatment of acute eosinophilic pneumonia. Eur Respir J 2013 Feb;41(2):402–9.   [CrossRef]   [Pubmed]    
21. Swartz J, Stoller JK. Acute eosinophilic pneumonia complicating Coccidioides immitis pneumonia: A case report and literature review. Respiration 2009;77(1):102–6.   [CrossRef]   [Pubmed]    
22. Vijayan VK, Reetha AM, Jawahar MS, Sankaran K, Prabhakar R. Pulmonary eosinophilia in pulmonary tuberculosis. Chest 1992 Jun;101(6):1708–9.   [CrossRef]   [Pubmed]