Sweet's syndrome associated with Staphylococcus aureus
Authors: Abramovits William , Stevenson Lisa C. 
Published: November 2004

On October 17, 2001, we examined a 47‐year‐old white woman with a 1‐week history of painful, burning, pruritic lesions on the arms (Fig. 1), legs, and back. Initial self‐treatment included Neosporin® and over‐the‐counter lotions with no response. Examination revealed several erythematous lesions, which appeared bullous, but felt solid on palpation and puncture. There was no mucosal involvement. A review of systems indicated generally good health with no fever, although the patient complained of fatigue and muscle aches. Her history included depression, hypertension, and anemia; her surgical history included cholecystectomy, excision of a soft tissue tumor, and spinal fusion.

The lesions on the patient's right arm were painful, pruritic, and erythematous, bullous in appearance, but solid on palpation

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She had also had two cesarean sections, the last of which coincided with her first episode of Sweet's syndrome in 1995. At that time, she developed diffuse, erythematous, urticarial papules on the right shoulder, both forearms, back, chest, both thighs, and left knee. Lesions also appeared in areas under bandages and after excoriations. A biopsy was performed, which confirmed Sweet's syndrome, and the patient was successfully treated with diphenhydramine hydrochloride (Benadryl®), diflorasone diacetate (Psorcon®), and a prednisone taper starting at 60 mg for the first week and ending with 20 mg on the third and last week. The patient suffered recurrences in April 1996 and again in October 1996, remaining well until October 2001.

Her medications at the initial visit included bupropion (Wellbutrin®), fluoxetine (Prozac®), gabapentin (Neurontin®), and hydrochlorothiazide, all of which she had taken for at least 2 years with no reported intolerance.

Bacterial culture and a punch biopsy from lesions on the left arm were obtained. Because the differential diagnoses included impetigo and ecthyma, the patient was treated with cetirizine (Zyrtec®), 10 mg at bedtime (q.h.s.), and cefdinir (Omnicef®), 300 mg twice daily (b.d.), prior to the arrival of the results of the culture and biopsy.

On October 19, the patient complained of increasing pain and redness associated with the lesions on her right forearm and legs. She was prescribed halobetasol (Ultravate®) ointment b.d. At an office visit on the following day, new lesions were present on the thighs. The bacterial culture revealed no microbial growth at 3 days, and by now a biopsy had again confirmed the diagnosis of acute febrile neutrophilic dermatosis (Sweet's syndrome), showing intense infiltration with neutrophils and a few lymphoid cells in the superficial dermis (Fig. 2). She was prescribed prednisone, 30 mg every day (q.d.), to be tapered by 10 mg every 4 days.

Biopsy results showed an intense infiltration of neutrophils in the superficial dermis, associated with edema, and a few lymphoid cells, favoring a diagnosis of acute neutrophilic dermatosis (Sweet's syndrome) (courtesy of Cockerell and Associates Dermatopathology Laboratories, Dallas, TX)

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A complete blood count (CBC) on October 22 disclosed anemia, with a low red blood cell count (3.48 × 106/µL), low hemoglobin (11.4 g/dL), low hematocrit (33.7%), increased platelets (17.0%), slightly high absolute neutrophils (401 × 103/µL), and a low absolute eosinophil count (31 cells/µL). The patient's comprehensive metabolic panel and total protein/protein electrophoresis analysis both returned normal values. The thyroid‐stimulating hormone (TSH) and glucose‐6‐phosphate dehydrogenase (G‐6‐PD) levels were also normal.

On October 29 (3 days short of completing the prescribed prednisone course), when the patient returned for suture removal, her blood pressure had increased to 144/108 mmHg. The prednisone taper was adjusted to 10 mg q.d. for 5 days, then 10 mg every other day (q.o.d.) for 5 days, concluding with 5 mg q.o.d. for three doses. Tacrolimus 0.1% ointment (Protopic®) b.d. was then prescribed in lieu of the halobetasol.

At a follow‐up visit on November 8, the patient complained of nausea and vomiting, increased sweating, and transient sensations of hot and cold over the preceding 3 days. Her blood pressure had continued to increase to 158/120 mmHg. The lesions on the legs had involuted and those on the arms were less inflamed, yet the patient did not feel that the treatments were helping. Prednisone was discontinued, and quinapril (Accupril®) was started to control her hypertension. She continued with topical tacrolimus, and clobetasol propionate (Clobevate®) gel b.d. was added.

On November 19, she complained of increasingly intolerable pruritus all over, pain, and new lesion development on the extremities. The lesions appeared vesiculated and ulcerated, and new violaceous plaques on the forearms and thighs had developed. Dapsone, 25 mg b.d., and hydrocortisone 2.5% with pramoxine lotion (Pramosone®) were prescribed. In late November, her primary care physician (PCP) also added atenolol as an additional treatment for her hypertension.

On November 27, a CBC revealed decreases in the red blood cell count (3.01 × 106/µL), hemoglobin (10.4 g/dL), and hematocrit (31.6%), with increases in the mean corpuscular volume (MCV) (104.9 fL), mean corpuscular hemoglobin concentration (MCHC) (34.4 pg), and red distribution width (RDW) (17.8%); all other values were normal. Indomethacin (Indocin®), 25 mg three times daily (t.d.s.) for 2 weeks, was prescribed for pain.

By November 30, some of the lesions had healed, whilst others looked intensely inflammatory and purulent. A bacterial culture from a leg lesion was positive for heavy growth of Staphylococcus aureus. Cefdinir (Omnicef®), 300 mg b.d., was prescribed again.

On December 4, the CBC showed further decreases in the red blood cell count (2.68 × 106/µL), hemoglobin (9.4 g/dL), and hematocrit (29.0%). The values for MCV (108.0 fL), MCHC (35 pg), and RDW (16.8%) were still high, the platelet count had increased (550 × 103/µL), and the absolute eosinophils were low (44 cells/µL). Occult blood tests detected blood in one of three specimens. On December 10, the patient complained of weakness, malaise, headaches, and severe epigastric pain. She felt that her condition was getting worse and she had one new bullous lesion. Cefdinir was replaced with amoxicillin/clavulanate (Augmentin®), 875 mg b.d., and dapsone was stopped.

Due to the abnormal hematology and the known association of Sweet's syndrome with bone marrow dyscrasias, the patient was referred to a hematologist. He agreed that her progressive anemia with macrocytosis was most probably a reaction to dapsone, in spite of the normal values of G‐6‐PD. A bone marrow aspirate and biopsy ruled out malignancy (no myelodysplasia nor myeloproliferative disorder).

By December 26, the patient's skin had improved significantly. There were no new lesions, but the old lesions on the extremities were still very pruritic and appeared purplish. She was now also taking dicyclomine for nausea and complained of muscle aches and weakness.

Her skin remained well until January 8, 2002, when she developed new lesions. She was given cefdinir, 300 mg b.d. Culture of a right forearm lesion was negative for aerobic bacteria.

On January 31, she had back surgery for a herniated disk and was given intravenous and oral steroids until February 10. By February 20, she was much improved, had no new lesions, and the old lesions were fading and flat.

On March 6, the patient reported three new small lesions which had erupted over the preceding 3 days.

On March 20, she presented with new lesions, vesicular in appearance, but again no fluid drained upon lancing. She was given amoxicillin/clavulanate (Augmentin®), 875 mg b.d. New bacterial cultures from lesions on both arms were later reported as negative. Her old lesions continued to improve, but she developed a few new lesions within a week of this visit.