Case Report
A 60-year-old man presented with eroded areas in the mouth and blistering eruptions on the scalp, face, trunk, arms, and legs. He initially presented to an outside hospital 4 years prior and was treated with oral prednisone 50 mg daily, to which the eruptions responded rapidly; however, following a nearly 5-mg reduction of the dose per week by the patient and irregular oral administration, he experienced several episodes of recurrence, but he could not remember the exact dosage of prednisone he had taken during that period. Subsequently, he was admitted to our hospital because of large areas of erythema and erosions on the scalp, trunk, arms, and legs.
Since starting the prednisone regimen 4 years prior, the patient had experienced onset of hypertension, diabetes, glaucoma, cataracts, optic nerve atrophy, aseptic necrosis of the femoral head, and osteoporosis. Biopsy of a new skin lesion revealed suprabasal acantholysis (Figure 1). Direct immunofluorescence showed epidermal intercellular deposition of IgG and complement component 3. Laboratory testing showed a desmoglein 1 level of 142 U/mL (reference range, <14 U/mL) and desmoglein 3 level of 150 U/mL (reference range, <14 U/mL). Liver and kidney function; routine blood and urine tests; and antinuclear antibody, hepatitis B and C antibodies, syphilis, and human immunodeficiency virus antibody levels were normal. The biopsy and immunofluorescence results combined with clinical feature were consistent with a diagnosis of pemphigus vulgaris (PV).
FIGURE 1. Biopsy of an early skin lesion on the trunk showed suprabasal acantholysis (H&E, original magnification ×100). Reference bar indicates 200 μm.
The patient initially was started again prednisone 50 mg daily, to which the skin eruptions responded, and 2 weeks later, the disease was considered controlled. The prednisone dosage was tapered to 20 mg daily 3 months later with no new blister formation. However, 2 weeks later, the patient was diagnosed by a tuberculosis specialist with pulmonary tuberculosis, and a daily regimen of isoniazid, rifampicin, ethambutol, and levofloxacin was instituted.
Ten days after starting antituberculosis therapy, the patient developed new erythematous blisters that could not be controlled and self-adjusted the prednisone dose to 50 mg daily. Two months later, blister formation continued.
Six months after the initial presentation, the patient returned to our hospital because of uncontrollable rashes (Figure 2). On admission, he had a Pemphigus Disease Area Index (PDAI) score of 32 with disease involving 30% of the body surface area. Laboratory testing showed a desmoglein 1 level of 233 U/mL and desmoglein 3 level of 228 U/mL. A tuberculosis specialist from an outside hospital was consulted to evaluate the patient’s condition and assist in treatment. Based on findings from a pulmonary computed tomography scan, which showed the inflammation was considerably absorbed, treatment was adjusted to stop using ethambutol and levofloxacin and continue rifampicin and isoniazid. For the PV, prednisone was titrated upward to 75 mg daily, mycophenolate mofetil (MMF) 1 g twice daily was added, and IVIG 400 mg/kg daily was administered for 7 days. After 3 weeks, the rash still expanded.
FIGURE 2. Pemphigus vulgaris. Crusted superficial erosions on the back.
In considering possible interactions between the drugs, we consulted the literature and found reports1-3 that rifampicin accelerated glucocorticoid metabolism, of which the tuberculosis specialist that we consulted was not aware. Therefore, rifampicin was stopped, and the antituberculosis therapy was adjusted to levofloxacin and isoniazid. Meanwhile, the steroid was changed to methylprednisolone 120 mg daily for 3 days, then to 80 mg daily for 2 days.
After 5 days, the rash was controlled with no new development and the patient was discharged. He continued on prednisone 80 mg daily and MMF 1 g twice daily.