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Dr Fayyaz Chaudhri. Maryport Health Services GPwSI. Solar (actinic) Keratosis. Background of solar elastosis multiple flat or thickened scaly or warty skin coloured or reddened lesions. cutaneous horn. www. dermnetnz.org. Treatment Options. Cryotherapy Curettage & cautery Excision
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Dr Fayyaz Chaudhri • Maryport Health Services • GPwSI
Solar (actinic) Keratosis • Background of solar elastosis • multiple flat or thickened • scaly or warty • skin coloured or reddened lesions. • cutaneous horn
Treatment Options • Cryotherapy • Curettage & cautery • Excision • 5-Fluorouracil cream • Imiquimod • Photodynamic therapy • Diclofenac gel
5-FU (efudix) useful when there are many lesions on the face. applied once or twice daily for two to four weeks. Expect inflammation - red, raw and uncomfortable. Good end results
5-Fluorouracil : Mechanism of Action 5-fluorouracil is a structural analogue of Thymine and Uracil with the 5-methyl group being replaced by fluorine. Its activity can be explained by two mechanism: F Thymine Uracil 5-fluorouracil Ref:Goette DK, J Am AcadDermatol 1981;4(6):633-649 UK/EFU/12/0007
5-Fluorouracil : Mechanism of Action • Metabolite competition • 5-FU competes with normal metabolites for access to • enzyme active sites and is eventually incorporated into the host cell RNA molecules. These become ineffective molecules for protein synthesis 1,2 • Enzyme inhibition • The 5-FU metabolite (5F-deoxyuridine monophosphate) • blocks the essential enzyme thymidylate synthetase thus preventing DNA synthesis 1,2 Ref:Goette DK, J Am AcadDermatol 1981;4(6):633-649 UK/EFU/12/0007
5-Fluorouracil : Mechanism of Action Ineffective mRNA Triplet does not code for an amino acid t-RNA F F 5-FU UK/EFU/12/0007
5-Fluorouracil : Mechanism of Action • Enzyme inhibition Enzyme inhibition Reduced DNA production x F DNA replication Making new copies for dividing cells 5-fluorouracil metabolite inhibits thymidylate synthetase UK/EFU/12/0007
2 weeks after Efudix treatment
5-Fluorouracil : Mechanism of Action • Therapeutic response depends on severity of disease • Phase 1 - early, mild inflammation • transformed cells die by necrosis leading to .... • Phase 2 - Severe inflammation • Phase 3 – lesion destruction and macrophage clearance • Phase 4 – Scabbing, new tissue production and healing process. Ref: Litwin MS, Ryan RF Reed Ej et al. J Surg Oncol 1971;3:351-65 UK/EFU/12/0007
Imiquimod • immune response modifier • 2-3 times weekly for 4-12 weeks. • inflammatory reaction, • results are variable, but generally excellent.