THE CLINICAL PICTURE TIMMIE SHARMA, MD ALOK VIJ, MD APRA SOOD, MD Department of , Department of Dermatology, Head, Section of Industrial Dermatology, University Hospitals Case Medical Center, Cleveland Clinic Department of Dermatology, Cleveland, OH Cleveland Clinic

Fungal masquerading as acute exanthematous pustulosis

25-year-old man being treated in the A hospital for catatonia and fl accid paraly- sis developed fever and a lobar consolidation, prompting treatment with piperacillin-tazo- bactam. A dermatology consult was called 3 days later when the patient developed a rash on the forehead (Figure 1), cheeks, chin, and upper trunk, raising concern for a drug-related eruption. Close examination of the rash revealed bright red plaques studded with sheets of monomorphic pustules. Possible causes other than drug therapy were considered, includ- ing folliculitis, acneiform eruption, and pus- tular psoriasis. Bacterial culture of a pustule was negative, but punch biopsy of a pustule FIGURE 1. A brightly erythematous plaque on the revealed an abundance of round and oval bud- forehead with monomorphic pustules was noted ding yeast forms consistent with on day 3 of piperacillin-tazobactam infusion. (formerly called Pityrosporum) “stuffi ng” the hair follicles and forming cleared spaces in the of acute generalized exanthematous pustulosis. surrounded by an exuberant lympho- It is a serious but uncommon adverse drug re- histiocytic infi ltrate (Figures 2 and 3). Spe- action, with a frequency of one to fi ve cases cial stains were negative for bacteria and my- per million per year. The eruption of erythem- celial forms. The clinicopathologic fi ndings atous plaques studded with sterile pustules were diagnostic of with classically appears 1 to 5 days after starting a formation of dermal . drug.1 Piperacillin-tazobactam has been infre- The patient was treated with intravenous quently reported in association with acute ex- 200 mg daily for 7 days and topi- anthematous pustulosis, but antibiotics in gen- cal benzoyl peroxide 5% gel, with ketocon- eral are among the most commonly reported azole 2% cream for maintenance therapy. culprits.2–4 The treatment brought improvement of the rash. Clues to the correct diagnosis Although our concern for acute localized ex- ■ THE DIFFERENTIAL DIAGNOSIS anthematous pustulosis was warranted, the morphology and distribution of this patient’s The appearance of sterile pustules after start- exanthem also raised suspicion of fungal fol- ing a new antibiotic raised suspicion for acute liculitis, which is more common. localized exanthematous pustulosis, a variant Malassezia folliculitis appears as a mono- morphic papular and pustular eruption on the doi:10.3949/ccjm.83a.15028 chest, back, and face,5 as in our patient. Differ-

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FIGURE 2. Histologic sections reveal Mal- FIGURE 3. Histologic sections of a perifol- assezia folliculitis and formation licular dermal abscess show mixed infl am- within the dermis. The red circle highlights matory infi ltrate including neutrophils and yeast forms within the follicular epithelium histiocytes centered on cleared-out spaces (hematoxylin and eosin, × 4). with small, grey-blue yeast forms (red ar- row) (hematoxylin and eosin, × 100). entiating fungal folliculitis from pustulosis is Take-home point important, as each condition is treated differ- Our experience with this patient was a re- ently: Malassezia folliculitis is treated with an- minder to consider fungal folliculitis in the tifungals,5 and acute localized exanthematous differential diagnosis of a pustular eruption, pustulosis is managed with cessation of the of- so as to allow appropriate management and fending drug, supportive care, and systemic or to avert discontinuation of potentially life- topical steroids.4 saving medications. ■ A rash that ■ REFERENCES 1. Fernando SL. Acute generalised exanthematous pustulo- 4. Huilaja L, Kallioinen M, Soronen M, Riekki R, Tasanen K. developed sis. Australas J Dermatol 2012; 53:87–92. Acute localized exanthematous pustulosis on inguinal 3 days after 2. Talati S, Lala M, Kapupara H, Thet Z. Acute generalized area secondary to piperacillin/tazobactam. Acta Derm exanthematous pustulosis: a rare clinical entity with use Venereol 2014; 94:106–107. Rubenstein RM, Malerich SA starting of piperacillin/tazobactam. Am J Ther 2009; 16:591–592. 5. . Malassezia (pityrosporum) Sidoroff A, Dunant A, Viboud C, et al folliculitis. J Clin Aesthet Dermatol 2014; 73:37–41. piperacillin- 3. . Risk factors for acute generalized exanthematous pustulosis (AGEP)- ADDRESS: Alok Vij, MD, Department of Dermatology, A61, tazobactam results of a multinational case-control study (EuroSCAR). Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; Br J Dermatol 2007; 157:989–996. e-mail: [email protected] prompted concern for exanthematous pustulosis

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