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Drug · Topical · Immunomodulator

Topical imiquimod

Aldara 5%; Zyclara 3.75%

Imiquimod is a Toll-like receptor 7 (TLR7) agonist that triggers innate and adaptive antitumour immune responses. Approved for actinic keratosis, superficial BCC, external genital warts and certain pre-malignant conditions; off-label use for Bowen's disease, lentigo maligna and as adjunct after incomplete BCC excision.

CurrentLast reviewed 25 March 2026

Indications

  • Actinic keratosis — field treatment; 3.75% formulation has shorter regimen.
  • Superficial BCC — cure rate ~75%; cosmetic outcome excellent.
  • Bowen's disease — off-label.
  • Lentigo maligna — second-line where surgery declined / unsuitable.
  • Genital warts (non-oncological).

Dosing

  • AK 5%: 3 nights/week for 4 weeks.
  • AK 3.75%: daily for 2 weeks, 2-week break, then daily for 2 weeks.
  • Superficial BCC 5%: 5 nights/week for 6 weeks.
  • Bowen's disease (off-label): daily for 6–16 weeks.
  • Lentigo maligna (off-label): daily or 5 nights/week for 8–12 weeks under specialist supervision.

Adverse events

  • Local inflammation: erythema, erosion, ulceration, scabbing — desired effect.
  • Influenza-like symptoms (fever, fatigue, myalgia) in ~20% — systemic immune activation.
  • Headache, lymphadenopathy.
  • Photosensitivity at treated site.
  • Hypopigmentation in some patients (often persistent).
  • Caution in OTRs — may trigger graft inflammation; lower-dose regimens preferred.
  • Pregnancy: avoid; reliable contraception.

References

  1. Bath-Hextall FJ et al. Surgical excision versus imiquimod 5% cream for nodular and superficial basal-cell carcinoma (SINS). Lancet Oncol; 2014.
  2. de Berker D, McGregor JM, Hughes BR. British Association of Dermatologists' guidelines for the care of patients with actinic keratosis 2017. Br J Dermatol. 2017;176(1):20-43.
  3. Nasr I, McGrath EJ, Harwood CA et al. British Association of Dermatologists guidelines for the management of adults with basal cell carcinoma 2021. Br J Dermatol. 2021;185(5):899-920.

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