Lymphocytic-variant hypereosinophilic syndrome (L-HES) L-HES is a subtype of HES caused by a clonal/aberrant T-cell population (typically CD3−CD4 ) that overproduces IL-5, driving persistent eosinophilia & eosinophil-mediated tissue injury. Common manifestations include severe pruritus, papules, plaques, urticaria-like eruptions, & erythroderma. There is a small risk of progression to T-cell lymphoma. This patient’s chronic intensely pruritic papular eruption, marked eosinophilia (AEC 10,500/µL), elevated IgE & TARC levels, monoclonal T-cell receptor rearrangement, and circulating aberrant CD3−CD4 T cells are most consistent with lymphocytic-variant hypereosinophilic syndrome (L-HES). Bx showed a superficial perivascular & interstitial infiltrate rich in eosinophils, supporting eosinophilic dermatosis. The absence of drug exposure, parasitic infection, autoimmune disease, or myeloid neoplasm further supported L-HES over idiopathic or secondary eosinophilia. Although he initially declined systemic corticosteroids, his disease progressed w/ intractable pruritus & widespread papules coalescing into plaques. Narrowband UVB (NB-UVB) provided partial relief of pruritus, but complete clinical resolution occurred only after addition of prednisone 30 mg/day, after which the steroid dose was successfully tapered while maintenance NB-UVB was continued.

Necrolytic migratory erythema (NME) NME is the characteristic cutaneous manifestation of glucagonoma syndrome. The dx in this patient was supported by the classic clinical presentation of migratory annular erythematous plaques with peripheral activity & central healing involving periorificial, intertriginous, & acral sites, together with weight loss, anemia, glossitis, & histopathologic findings of superficial epidermal necrolysis with vacuolated keratinocytes. Although NME may occur in pseudo-glucagonoma states associated w/ nutritional deficiencies, the eruption failed to improve despite zinc supplementation & nutritional repletion. Metabolic evaluation demonstrated elevated plasma glucagon with endogenous hyperinsulinemic hypoglycemia, and abdominal CT identified a 12 × 14 cm pancreatic head mass. Biopsy confirmed a well-differentiated grade 2 pancreatic neuroendocrine tumor w/ metastatic disease. The coexistence of hyperglucagonemia & hyperinsulinemic hypoglycemia suggests either co-secretion of glucagon & insulin by the tumor OR inappropriate hyperglucagonemia insufficient to overcome tumor-driven insulin excess. B/c the tumor was unresectable, tx w/ lanreotide, everolimus, & diazoxide was initiated, resulting in marked improvement of the cutaneous eruption w/in 4 wks.

Generalized lichen planus (LP) LP is an uncommon variant characterized by widespread intensely pruritic, flat-topped papules & plaques. Histopath in this patient demonstrated a classic lichenoid interface dermatitis w/ a band-like lymphocytic infiltrate and effacement of the dermoepidermal junction, confirming LP. Given extensive disease (~80% BSA) & failure of topical corticosteroids, tx options include systemic corticosteroids, acitretin, methotrexate, cyclosporine, & other immunomodulators. The patient declined traditional systemic immunosuppression b/c of concerns regarding adverse effects & was started on deucravacitinib (Sotyktu®️) 6 mg daily. W/in 3 mos, she achieved near-complete clearance w/ marked improvement in pruritus, leaving only residual post-inflammatory hyperpigmentation & a few new lesions (see infra). The therapeutic rationale is supported by increasing evidence implicating TYK2-dependent cytokine signaling, including type I interferons & IL-23–related pathways, in LP pathogenesis.