Sociedad Americana de Hirudoterapia

Chronic Idiopathic Urticaria (Investigational Adjunct)

Investigational adjunct for chronic spontaneous urticaria refractory to high-dose H1 antihistamines; omalizumab, cyclosporine, and step-up guideline-directed therapy remain evidence-based.

Tier C — InvestigationalInvestigacionalLast updated: 2026-05-26 · Reviewed by ASH Editorial Board

Resumen para el Paciente

¿Está esto autorizado por FDA para este uso?
Not FDA-cleared for chronic idiopathic / spontaneous urticaria. FDA cleared medicinal leeches only for venous congestion in microsurgical reconstruction (K040187, June 2004). Use here is Tier C investigational.
¿Qué evidencia existe?
Tier C (investigational). No controlled trials. Evidence-based first-line management is second-generation H1 antihistamines at standard doses, uptitrated up to fourfold if needed, addition of H2 antihistamine or leukotriene receptor antagonist, omalizumab (FDA-approved for chronic spontaneous urticaria refractory to antihistamines), and for refractory disease cyclosporine or other immunomodulators under specialist supervision.
Riesgos principales
  • Bleeding from each bite site for 6 to 10 hours after the leech detaches
  • Iron-deficiency anemia from cumulative blood loss across multiple sessions
  • Aeromonas hydrophila wound infection from leech gut bacteria (uncommon outside reconstructive surgery, but possible)
  • Allergic reaction to leech saliva (rare; ranges from local itching to anaphylaxis)
  • Permanent Y-shaped bite-mark scars or hyperpigmentation at attachment sites
  • Local pain, bruising, swelling, or itching for 1 to 3 days after each session
  • Allergic reactions to leech proteins may be misinterpreted as urticaria flare
  • Risk of anaphylaxis (already concerning in this population)
  • Triggering urticarial flare from cutaneous trauma
Quién no debería considerar esto
  • Patients who have not had fourfold-uptitrated H1 antihistamine for 4+ weeks
  • Patients eligible for omalizumab who have not been offered it
  • Patients with known anaphylaxis to leeches or other arthropod proteins
  • Patients with autoimmune urticaria with positive autologous serum skin test (these may need immunomodulators)
  • Anyone on blood thinners such as warfarin, apixaban, rivaroxaban, dabigatran, heparin, or daily aspirin used for medical reasons
  • People with hemophilia or any other inherited bleeding disorder
  • Patients with severe anemia (hemoglobin under 10 g/dL)
Qué preguntar a su clínico
  • Have I been on fourfold-uptitrated H1 antihistamine?
  • Has omalizumab — FDA-approved for chronic spontaneous urticaria — been considered?
  • Have triggers and physical urticaria types been ruled out?
  • What is the published evidence base for leeches in CIU?
  • What is the plan if my urticaria flares severely from bites?
  • What is the anaphylaxis-prevention plan?
Cuándo buscar atención urgente
  • Bleeding from a bite site that soaks through more than one dressing per hour
  • Bleeding that continues more than 24 hours after the leech detached
  • Spreading redness, warmth, swelling, pus, or red streaks around any bite site
  • Fever over 38.0 C / 100.4 F, chills, or feeling suddenly unwell after a session
  • Hives, facial or tongue swelling, throat tightness, or any difficulty breathing
  • Sudden weakness, dizziness, fast heart rate, or fainting (possible severe blood loss)
  • Severe widespread hives with throat swelling, breathing difficulty, lightheadedness, or vomiting (anaphylaxis — emergency)
  • Sudden severe abdominal pain or syncope

Qué NO significa esto

  • It does not mean leech therapy is FDA-cleared for urticaria — the only FDA clearance is venous congestion in microsurgical reconstruction (K040187, June 2004).
  • It does not replace fourfold-uptitrated H1 antihistamines or omalizumab.
  • It does not modify the underlying mast cell pathology.
  • It risks anaphylaxis from leech proteins in a population already prone to allergic reactions.
  • It does not have controlled-trial evidence in CIU.

Clinical Profile

Category
dermatological
ICD-10
L50.1, L50.8, L50.9
Safety tier
high

Evidence Summary

Chronic spontaneous (idiopathic) urticaria is daily or near-daily wheals with or without angioedema persisting more than 6 weeks. Step-up management per international guideline: second-generation H1 antihistamine at standard dose, then up to 4x dose, then add omalizumab (anti-IgE), then cyclosporine for refractory disease. Short corticosteroid bursts for severe flares only. Trigger identification is rarely successful in true idiopathic disease. No published controlled trials of hirudotherapy exist for chronic urticaria. Direct application to active wheals is contraindicated; placement on lesion-free skin has been mentioned anecdotally in central European naturopathic literature without efficacy or safety data, and may itself trigger urticarial reaction.

Treatment specifics

How many leeches, where they are placed, how long a session lasts, and whether to repeat are clinical decisions made by a qualified provider under institutional protocol — not something to self-administer. Discuss the specifics with a clinician experienced in medicinal leech therapy. (Clinicians: switch the audience selector in the top bar to “Clinician” to view protocol detail.)

Contraindications

  • Active anticoagulant therapy (warfarin INR >2.0, DOACs, heparin)
  • Hemophilia or other bleeding disorder
  • Severe anemia (Hb <10 g/dL)
  • Active bacteremia or sepsis
  • Known hypersensitivity to leech salivary proteins
  • Pregnancy (relative — first/third trimester)
  • Immunocompromised state with severe neutropenia
  • Active urticarial flare or angioedema
  • Prior anaphylaxis to insect or arthropod bites
  • Concurrent ACE inhibitor or NSAID-induced angioedema
  • Cold urticaria, cholinergic urticaria, or other physical urticarias (placement triggers flare)
  • Pediatric or geriatric patient with cardiovascular disease (anaphylaxis risk)

Related Conditions

Este sitio web proporciona información educativa y no constituye consejo médico, diagnóstico ni recomendaciones de tratamiento. La terapia con sanguijuelas medicinales conlleva riesgos clínicamente significativos y debe ser realizada únicamente por profesionales calificados bajo protocolos aprobados institucionalmente. La autorización 510(k) de la FDA para sanguijuelas medicinales se limita a indicaciones específicas; las discusiones sobre uso investigativo y fuera de indicación se señalan correspondientemente. Para orientación médica específica, consulte a un profesional de salud calificado.

Chronic Idiopathic Urticaria (Investigational Adjunct) — Hirudotherapy Evidence | ASH