In the Chair puts you in the hot spot, challenging you to navigate complex, real-world cases.
Most patients with psoriasis or atopic dermatitis (AD) fit neatly into one immunologic lane. Psoriasis runs on the Th17/IL-23 axis, whereas AD runs on Th2/IL-4/IL-13.1,2 The biologics developed for each disease reflect that distinction, and they work well—until a patient walks in who belongs to both lanes at once.
Psoriasis-AD overlap is more than a clinical curiosity. Patients present with mixed histology—psoriasiform spongiotic dermatitis with concurrent Th17 and Th2 signatures—and single-pathway biologics can paradoxically worsen the component they weren’t designed to treat. For clinicians managing these patients, that means more treatment failures, more frustrated patients, and a narrower therapeutic margin.
The 4 cases below, drawn from a 2026 case series by Bongiovanni and colleagues published in JEADV Clinical Practice, put you in the treating clinician’s seat.3 For each patient, review the clinical picture, decide what you’d do, and then see how the case resolved and why.
A 47-year-old woman with allergic rhinitis develops pruritic erythematous, exudative, and crusted lesions starting on the face and spreading to the palms, soles, mammary region, abdomen, and dorsal area. Lesions evolve into vesiculobullous and annular plaques with scaly borders. Laboratory workup is negative. Biopsy shows psoriasiform dermatitis with parakeratosis, acanthosis, and a prominent eosinophilic infiltrate. She has not responded to cyclosporine, triamcinolone injections, or terbinafine.
📋WHAT WOULD YOU DO?
Your workup rules out infection and autoimmune blistering disease. Biopsy confirms a mixed psoriasiform-eczematous pattern. What do you initiate next?
A 49-year-old woman presents with a widespread, intensely pruritic eruption involving the scalp, face, neck, ears, nipples, inframammary folds, umbilicus, extensor limbs, and genitalia. Scalp lesions are markedly hyperkeratotic with adherent psoriasiform scale; neck, ears, and nipples show predominantly eczematous erythema and desquamation. Two biopsies confirm psoriasiform spongiotic dermatitis. She has failed cyclosporine and bimekizumab.
📋WHAT WOULD YOU DO?
After cyclosporine and bimekizumab both fail and a biopsy confirms a mixed psoriasiform-eczematous pattern, what is your next move?
A 55-year-old woman has severe eczematous dermatitis of the scalp and auricular pinnae, chronic plaque psoriasis on the extensor limbs, nail dystrophy, and psoriatic arthritis (axial sacroiliitis and peripheral polyenthesitis). Prior therapies include hydroxychloroquine, methotrexate, etanercept, adalimumab, and secukinumab. The IL-17 inhibitor partially improved joint symptoms but worsened the eczematous dermatitis component.
📋WHAT WOULD YOU DO?
Your patient’s IL-17 inhibitor is helping her joints but worsening her eczematous dermatitis. She has failed 2 TNF inhibitors. What is your next step?
A 63-year-old woman has a 10-year history of psoriasis. She presents with severe hyperkeratotic plaques on the palms and dorsal feet and intense pruritus, refractory to methotrexate, acitretin, cyclosporine, and the anti–IL-17 agent ixekizumab.
📋WHAT WOULD YOU DO?
A patient with a decade of psoriasis, palmoplantar involvement, severe pruritus, and failure of 4 prior therapies, including an IL-17 inhibitor, presents to your clinic. What do you reach for?
✓Severe pruritus disproportionate to plaque load
✓Eczematous lesions on the face, neck, or folds, alongside psoriatic plaques
✓Nail involvement or psoriatic arthritis (axial or peripheral)
✓Psoriasiform spongiotic histology on biopsy
✓Prior single-pathway biologic failure—or paradoxical worsening of 1 disease component
Across these 4 cases, Janus kinase (JAK) inhibition delivered what single-pathway biologics could not: simultaneous control of psoriasiform and eczematous inflammation in patients who didn’t cleanly fit either disease category. Pruritus resolved within 2 weeks in 3 of 4 patients, an early clinical signal worth monitoring. Near-complete cutaneous responses were achieved in 2 patients, rheumatologic stability was maintained in a third after multiple biologic failures, and the fourth case underscored the importance of recognizing superimposed infection in barrier-disrupted skin.
What this series reinforces for advanced practice providers: The diagnosis is the strategy. When a patient’s histology and clinical picture reflect both diseases, the therapeutic approach needs to match that complexity. JAK inhibitors offer pleiotropic coverage across the divergent cytokine axes driving overlap, but they require the same meticulous pretreatment workup and ongoing safety monitoring as any systemic agent. Patient selection, dose optimization, and vigilance for infection remain essential.
Larger prospective studies are needed to define durability, optimal dosing strategies, and long-term safety in this phenotype. In the meantime, these cases offer a practical framework for the patients already sitting in your chair.
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