Severe atopic dermatitis
Chronic, severe inflammatory skin disease with barrier dysfunction (filaggrin loss-of-function), Th2 immune dysregulation (IL-4, IL-13, IL-31, TSLP), and intractable pruritus — recalcitrant to topical therapy and managed by dermatology with biologics, JAK inhibitors, and structured skincare. EASI >21, IGA 4, BSA >30%. Pediatric onset common (~60% by age 1); ~30% persist into adulthood. Atopic march into asthma + allergic rhinitis + food allergy. Comorbidities: depression + elevated suicide risk + sleep disturbance. Hanifin-Rajka criteria + UK Working Party. Standard-of-care escalation: foundation emollients + gentle skincare + trigger avoidance + dilute bleach baths for S. aureus colonization → topical corticosteroids + topical calcineurin inhibitors (tacrolimus + pimecrolimus) + topical PDE4 (crisaborole + roflumilast) + topical JAK (ruxolitinib cream FDA Sept 2021) → phototherapy (NB-UVB) → oral immunosuppressants (cyclosporine + methotrexate + MMF + AZA) → BIOLOGICS PARADIGM SHIFT: DUPILUMAB (Dupixent) anti-IL-4Rα FDA March 2017 (pediatric down to 6 months); TRALOKINUMAB (Adbry) anti-IL-13 FDA Dec 2021 via ECZTRA; LEBRIKIZUMAB (Ebglyss) anti-IL-13 FDA Sept 2024 via ADvocate + ADhere; NEMOLIZUMAB (Nemluvio) anti-IL-31RA FDA Dec 2024 AD via ARCADIA. ORAL JAK INHIBITORS: UPADACITINIB (Rinvoq) JAK1 FDA Jan 2022; ABROCITINIB (Cibinqo) JAK1 FDA Jan 2022. JAK BOXED WARNING — VTE + MACE + malignancy. Emerging: rocatinlimab + amlitelimab anti-OX40/OX40L Phase 3. National Eczema Association + International Eczema Council + ETFAD. Forty-fourth deliberate non-elevation.
What changes during this transition
Severe atopic dermatitis (AD) — EASI >21, IGA 4, body surface area involvement >30%, or disease that has failed optimized topical therapy — is a dermatologist-managed disease, not a peptide-managed one. The pathophysiology is now well-characterized: filaggrin loss-of-function variants drive barrier dysfunction; Th2 cytokines (IL-4, IL-13, IL-31, TSLP) drive itch and inflammation; Staphylococcus aureus colonization and broader microbiome dysbiosis amplify flares. The clinical phenotype is intractable pruritus, lichenification, recurrent skin infections, sleep disturbance, and — at the severe end — major mental-health comorbidity including depression and elevated suicide risk. Roughly 60% of cases onset by age 1, and about 30% persist into adulthood; the atopic march into asthma, allergic rhinitis, and food allergy means severe pediatric AD often arrives with multi-system comorbidity. Standard of care has transformed since 2017. Foundation remains emollients, gentle skincare, trigger avoidance, topical corticosteroids, topical calcineurin inhibitors (tacrolimus, pimecrolimus), topical PDE4 (crisaborole, roflumilast), and — newer — topical JAK (ruxolitinib cream, FDA Sept 2021). Phototherapy (narrowband UVB) sits between topical and systemic. Above that, the systemic landscape has been rebuilt: dupilumab (Dupixent, anti-IL-4Rα, FDA March 2017, now down to age 6 months) was the paradigm shift, followed by tralokinumab (Adbry, anti-IL-13, FDA Dec 2021), lebrikizumab (Ebglyss, anti-IL-13, FDA Sept 2024), and nemolizumab (Nemluvio, anti-IL-31RA, FDA Dec 2024 for AD). The oral JAK inhibitors upadacitinib (Rinvoq, JAK1, FDA Jan 2022) and abrocitinib (Cibinqo, JAK1, FDA Jan 2022) carry the class-wide boxed warning for venous thromboembolism, major adverse cardiovascular events, and malignancy — load-bearing safety considerations that shape who gets them. Older oral immunosuppressants (cyclosporine, methotrexate, mycophenolate, azathioprine) still have a place, particularly for bridge therapy. The emerging pipeline — rocatinlimab and amlitelimab (anti-OX40/OX40L), IL-22 and IL-31 axis agents — is rapidly expanding. Within that landscape, the peptide-community framings users encounter — BPC-157 for 'skin healing,' KPV as a topical α-MSH anti-inflammatory, LL-37 as a barrier-defense cathelicidin, TA-1 as an immune modulator, NMN for cellular resilience — do not slot into severe AD as alternatives to dupilumab, JAK inhibitors, or guideline-directed topical therapy. Some have mechanistic adjacency worth surfacing honestly; several have directional mismatches that argue against use. None have severe-AD trials. The 'gut-skin axis' framing around BPC-157 conflates wound healing with Th2-driven inflammatory skin disease — different pathophysiology, different intervention category. Severe AD is where the modern biologic and small-molecule armamentarium genuinely changes lives; the peptide layer is not where the lift comes from, and in some cases (LL-37, TA-1) the mechanism runs in the wrong direction for this disease.
Important caveat
Severe atopic dermatitis is a dermatologist-managed disease. DUPILUMAB (Dupixent FDA March 2017 anti-IL-4Rα — paradigm shift, pediatric down to 6 months), TRALOKINUMAB (Adbry FDA Dec 2021 anti-IL-13), LEBRIKIZUMAB (Ebglyss FDA Sept 2024 anti-IL-13), NEMOLIZUMAB (Nemluvio FDA Dec 2024 anti-IL-31RA), oral JAK inhibitors (upadacitinib Rinvoq + abrocitinib Cibinqo FDA Jan 2022), phototherapy (NB-UVB), topical steroids, topical calcineurin inhibitors (tacrolimus + pimecrolimus), topical PDE4 (crisaborole + roflumilast), topical JAK (ruxolitinib cream FDA Sept 2021), dilute bleach baths for staph colonization, and structured emollient regimens are the load-bearing interventions. Peptides do not substitute. JAK BOXED WARNING is load-bearing — venous thromboembolism + major adverse cardiovascular events + malignancy class-wide; shapes who gets oral JAK. LL-37 specifically carries directional concern — biphasic biology, pro-inflammatory at higher concentrations, self-antigen in psoriasis; the 'AD skin has low LL-37, therefore add LL-37' inference is tidier than the biology supports. Thymosin alpha-1 carries opposite-direction concern — T-cell augmentation in a Th2-polarized disease where every approved biologic is designed to dampen Th2 cytokines. Severe AD carries elevated depression and suicide risk — mental health screening (PHQ-9 minimum) is part of standard care; 988 Suicide and Crisis Lifeline (US) if needed. Pediatric severe AD population requires pediatric dermatology coordination — most peptide-prescribing clinics are not equipped for IGA 4 disease in any age group. WADA athletes: BPC-157 (S0) prohibited at all times. Pregnancy: dupilumab pregnancy data accumulating + topical steroids continued; JAK inhibitors and most oral immunosuppressants have pregnancy-specific guidance; coordinate dermatology + maternal-fetal medicine. National Eczema Association + International Eczema Council + ETFAD patient organizations are legitimate first stops.
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