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Actinic (Solar) Keratosis - Coggle Diagram
Actinic (Solar) Keratosis
Non-Pharmacological Treatments
Sunscreen
Physical = reflects visible light and works as chemical filters in the UV range
Chemical = absorbs both UVA and UVB light and converts it into heat
Education point:
on how much sunscreen to apply
Wearing a hat/covering self with clothing
Photodynamic therapy
Uses photosensitising agents (via oral, topical or IV), oxygen and light, to create a photochemical reaction that selectively destroys cancer cells; usually for actinic keratoses on face and scalp
Cryotherapy
Liquid nitrogen on lesions; usually for isolated and hyperkeratotic actinic keratoses
Shave, curettage, electrocautery
Remove a cutaneous horn or hypertrophic actinic keratosis
Curettage = scarping with sharp instrument
Electrocautery = burning
Excision
Surgical removal of actinic keratosis
Pharmacological Treatments
Imiquimod
Prescription; 5% cream
Immune response modifier
- thought to cause inflammation and infiltration of lymphocytes, dendritic cells, macrophages into lesions, to stimulate apoptosis of affected cells.
Adverse effects:
local reactions; influenza-like symptoms; myalgia; headache
Education points:
should be rubbed in and allowed to stay on for 8 hours (typically overnight, before bed), then washed off with mild soap and water; do not apply on eyes, nose, lips; skin will probably look worse and may feel uncomfortable - signs that the imiquimod is working;
Monitoring:
Experiencing extensive pain or adverse reactions such as black scabs and ulcers = stop using imiquimod and seek a doctor asap
Dose:
apply to lesion 3x a week for 4 weeks; assess response after a 4-week treatment-free interval; repeat 4-week course if lesions persist; max. 2 courses
5-Fluorouracil (5-FU)
Prescription; 5% cream
Antimetabolite
- inhibits DNA and RNA synthesis to prevent cell division in rapidly dividing cells
Adverse effects:
local reactions; hyperpigmentation; scarring; drug-induced photosensitivity reactions; erythema multiforme
Education points:
avoid excessive exposure to sunlight; do not apply on eyes, nose, lips; wash hands after application; do not apply before bed - contact with pillows or sheets may result in undesirable spreading to unaffected areas
Monitoring:
Feel unwell with nausea, vomiting or diarrhoea, or get mouth ulcers = let doctor or pharmacist know immediately
Dose:
apply thinly to the affected area once or twice daily; usual duration of initial therapy, 3–4 weeks; max. area of skin treated at one time, 500 cm2
Nicotinamide
Water-soluble,
active form of vitamin B3
Reduces UV induced immunosuppression as it prevents ATP depletion to enhance DNA repair (including UV induced DNA damage)
OTC; 500mg tablets
Reduces scaly actinic keratosis
Pre-disposing Factors
Other signs of photoageing skin
Fair skin with a history of sunburn
History of long hours spent outdoors for work or recreation
Defective immune system
Clinical Features
A flat or thickened papule or plaque
White or yellow; scaly, warty or horny surface
Skin coloured, red or pigmented
Tender or asymptomatic
Scaly spot found on sun-damaged skin (chronic) - considered precancerous or early form of cutaneous SCC
Abnormal skin cell development due to DNA damage by short wavelength UVB