The Patient Who Doesn't Match the Textbook
Buchi Neita, PA-C, and Shanna Miranti, PA-C, open the discussion by asking their guest Douglas DiRuggiero, PA-C, to describe the typical bullous pemphigoid (BP) patient — and his first pearl is that they rarely look like the textbook photos. DiRuggiero notes that roughly 20% of BP patients present with only a pruritic or urticarial presentation before they ever manifest vesicles and bullae.
His practical rule: any patient over the age of 65 presenting with chronic itch, with or without urticaria, is bullous pemphigoid until proven otherwise. He points out that risk climbs with every decade of life — a person living past 90 is 80% more likely to develop BP than someone between 60 and 70. Incidence is nearly equal between men and women and across ethnic groups, though he notes small nuances: bullous presentations skew slightly toward men aged 80 and older, and pruritic presentations slightly toward women 80 and beyond.
Why the Blisters Are Tense — and Why the Elderly Fool You
DiRuggiero grounds the clinical picture in the pathophysiology. BP is a true autoimmune disease with identified autoantibodies — BP180 and BP230 — where the body creates an attacker cell against the skin's adhesion cells. In BP, the attack occurs below the dermal-epidermal junction, obliterating the hemidesmosomes so the skin separates and the body fills the empty space with fluid. Because the full thickness of the epidermis sits above that split, the resulting blister is tense enough that 'you almost have to take something sharp to get it to rupture.'
He contrasts this with pemphigus disorders, where the attack happens within the epidermis on the desmosomes between spinous and granular cells, producing thin, shallow, fragile blisters that often rupture before the office visit. The caveat for APPs: the older the patient, the thinner the skin. An 85- or 90-year-old with atrophic, sun-damaged, purpuric skin can develop BP and still look pemphigus-like — especially on highly sun-exposed areas. DiRuggiero advises examining less-radiated sites for more classically tense lesions, and always checking mucosal surfaces (eyelids, nose, mouth, genitalia), since mucosal involvement points more toward pemphigus vulgaris or mucous membrane pemphigoid. BP itself, he notes, can present anywhere — trunk, extremities, head, and neck.
Working Up the Itchy Elderly Patient
Asked how he should keep BP high on the differential, DiRuggiero says the only way to definitively rule it in or out is biopsy — and typically two of them. The first is a punch biopsy capturing about one-third blister and two-thirds adjacent skin, sent in formalin for H&E. The second is taken at least one centimeter away from a lesion, where activity is present but separation hasn't yet occurred, and placed in Michel's medium (or normal saline if it can be fully processed within 72 hours) for direct immunofluorescence.
On DIF, BP typically shows sub-epidermal separation with IgG and complement 3 lining up, and the H&E shows the same separation with a high influx of eosinophils, sometimes neutrophils. DiRuggiero also mentions serum testing — indirect immunofluorescence or ELISA for BP180 and BP230 levels — noting that a small subset (about 7–10%) can have positive serum without skin manifestations. He references the BP clinics at Cleveland Clinic and John Zone's work, where serum levels track response to therapy. DiRuggiero frames the broader itchy-elderly workup as putting on the thinking cap: Is it malignancy, drug-induced, neuropathic, or truly unexplained pruritus? His warning to APPs is not to reflexively blame xerosis and aging.
Therapy: Steroids Up Front, Then Getting Them Off
When the hosts steer toward treatment, DiRuggiero is clear that systemic steroids remain the drug of choice to get patients under control up front — and not a Medrol dose pack or a two-week taper. He describes doses ranging from 0.5 to 1 or even 1.5 mg/kg, tapered by at most 0.5 mg/kg every two weeks, often starting at 80 mg orally and stepping down over two to three months. Taper too fast, he warns, and patients recur.
The steroid-sparing armamentarium includes the tetracyclines (doxycycline, minocycline), dapsone, nicotinamide as an adjunct, methotrexate, and mycophenolate — the last of which DiRuggiero uses heavily. For mucosal or pemphigus-type disease, rituximab is the drug of choice, and he calls it near-malpractice not to start rituximab promptly in ocular pemphigus given its rapid progression.
The headline, DiRuggiero notes, is that dupilumab is now the first-ever FDA-approved medication for BP. He describes the trial design: patients washed off topicals, started on systemic steroids (0.5 mg/kg for mild-moderate, 0.75 mg/kg for more severe), tapered completely off by week 16, and had no new lesions for two weeks before a maintenance period. He characterizes dupilumab's mechanism against the IL-4/IL-13 receptor, TH2-driven disease, not as a sniper shot but 'a shotgun blast' — broad but effective. Of his own four patients started on dupilumab at the standard 300 mg every-two-week adult dose, all were tapered off steroids with good maintenance of response. On chronicity, he contrasts the easier conversation around dupilumab — approved down to six months of age, without the immunosuppressive burden — with the blood-monitoring headaches of methotrexate and mycophenolate, where he's the one asking how soon and how low he can go.