​Kembara Xtra - Medicine - Actinic Keratosis

​Kembara Xtra - Medicine - Actinic Keratosis 
Regular, frequently numerous premalignant lesions on skin exposed to the sun. Most resolve on their own, and only a tiny percentage develop into squamous cell carcinoma (SCC).
Common result of prolonged exposure to ultraviolet (UV) light Alternative name(s): sun keratosis
Aspects of Geriatrics
Regular issue
Child Safety Considerations
Infrequent (if a youngster, look for freckling and other xeroderma pigmentosum stigmata) 

Epidemiology 
Incidence
Rates change based on age and sun exposure.
Males outnumber women in terms of gender preference. It is more common in those with blonde and red hair and less common in people with darker skin tones.
​
Prevalence

Actinic keratoses (AKs) have an age-adjusted prevalence rate of 6.5% in Caucasians in the United States, 55% in 65- to 74-year-old males, and 18% in those with limited sun exposure.


Pathophysiology and Etiology 
The basal layer of the epidermal lesions is characterized by aberrant keratinocytes that sporadically extend upward. There are mitoses. The differentiation depends on the degree of epidermal involvement, and the histopathologic characteristics mimic those of SCC in situ or SCC.
 Genetics of cumulative UV exposure
Both AKs and SCCs have regularly been shown to have the p53 chromosomal mutation. Recently, it has been discovered that many novel genes express themselves similarly in AKs and SCCs.

Risk factors include: Skin type, burns readily, does not tan; exposure to UV light; long-term and/or repetitive exposure from outdoor employment or recreation; immunosuppression, particularly organ transplantation 

Prevention 

Avoiding the sun and using sunscreen are beneficial.

Lentigines, elastosis, and telangiectasias are further signs of chronic sun damage. Associated Conditions: SCC 

The lesions are generally asymptomatic, however symptoms such as itching, burning, and moderate hyperesthesia are possible.
Lesions could get bigger, thicker, or scalier. They might also stagnate or go backward.
The majority of lesions develop on the hands, arms, neck, and other exposed skin.

clinical assessment 

 Usually small (1 cm), numerous rough-to-palpate red, pink, or brown macules, papules, or plaques.
On top of the lesion, adhering scaling that is yellow or brown is frequently visible.
There are numerous clinical variations.
- Atrophic: dry, scaly macules with erythematous bases and fuzzily defined borders - Hypertrophic: Clinically, cutaneous horn, a severe form of overlying hyperkeratosis, may be difficult to distinguish from SCC.
- Pigmented: centrifugally spreading smooth tan/brown plaque - Bowenoid: red, bordered plaques with scaly scales.
- Actinic cheilitis: an inflammation that typically affects the lower lip 

SCC (hypertrophic form), Keratoacanthoma, Bowen disease, and basal cell carcinoma are the possible diagnoses.
Verruca vulgaris Less likely: lentigo maligna, solar lentigo, discoid lupus erythematosus, warty dyskeratoma, lichenoid keratoses, seborrheic keratoses, porokeratoses, seborrheic dermatitis or psoriasis (near hairline),

Results from the laboratory Diagnostic techniques/Other
With the exception of cases when there is a suspicion of cancer, the diagnosis is often made clinically.
When lesions are big, ulcerated, indurated, bleeding, or unresponsive to treatment, a skin biopsy is especially advised.
Interpretation of Tests
Lower layers of the epidermis with dysplastic keratinocytes and a dermal lymphocytic infiltration Neoplastic cells are cytologically identical to SCCs and are primarily seen in the lower epidermal layers.
Neoplastic cells will be classified as an SCC in situ or an invasive SCC, respectively, if they penetrate the entire epidermis or the dermis.
Malignant cells are rare, with the exception of bowenoid cells, which have the same epidermal characteristics as hypertrophic, atrophic, bowenoid, acantholytic, and pigmented cells.

Management 

Cryotherapy is the first-line therapy (technically, this is regarded as surgery, particularly by insurance companies). Medical treatment (also known as "field therapy") is often only used for severe or numerous AKs.
Compared to monotherapy, cryotherapy in combination with a topical method considerably increased full clearance rates.


Sunscreens and other physical sun protection are advised as general precautions. 

First Line of Medicine

With the exception of generic 5-fluorouracil, pharmaceutical costs are substantial ($600 to $1,200 each course), targeting both apparent and subclinical lesions.
 Every day—BID for 3 to 6 weeks for topical fluorouracil (Efudex, Carac, Fluoroplex cream, Fluoroplex solution)—depending on the brand, concentration, and formulation - Can be extremely grating
- Among the topical remedies listed in this section, probably the most efficientTopical imiquimod (Aldara) 5% cream should be applied to a small area no larger than the forehead or one cheek twice weekly at HS for up to 16 weeks.
- May be upsetting
Topical imiquimod (Zyclara) 3.75% cream: Apply once daily for 2 weeks, then for the next 2 weeks refrain from therapy. Then, apply once daily for an additional 2 weeks.
- May be upsetting
Topical ingenol mebutate (Picato) 0.015% and 0.05% gel should be applied once daily for three days straight to the face and scalp.
- Use on the trunk and extremities once daily for two days in a row.
It should only be applied to one continuous skin region that is no more than 25 cm2.
Herpes zoster reactivation and severe allergic responses (including anaphylaxis) unrelated to application mistakes have also been observed.
- Picato is no longer legal in the EU because LEO Laboratories Ltd. requested the withdrawal of the marketing license on February 11, 2020.
Apply the 3% diclofenac (Solaraze) gel BID for 60 to 90 days.

Second line: Systemic retinoids are rarely utilized, however topical tretinoin (Retin-A) or tazarotene (Tazorac) may be used to increase the effectiveness of topical fluorouracil. 

Further Therapies 

For minor lesions, close observation without therapy is an appropriate alternative.

Cryosurgery ("freezing," "liquid nitrogen") is the most used surgical procedure for treating AK.
Photodynamic therapy with a photosensitizer (e.g., aminolevulinic acid) and "blue light" may be superior to photodynamic therapy for thicker lesions. - Cure rate: 75-98.8% - May produce atrophy and hypopigmentation - May clear >90% of AKs Less scarring than cryotherapy - Cryotherapy may not always be the best option, especially when more skin is involved. Curettage and electrocautery (electrodesiccation and curettage [ED&C]; "scraping and burning"), medium-depth peels, particularly for the treatment of vast areas, CO2 laser therapy, dermabrasion, and surgical excision (excisional biopsy) are some of the procedures that can be used to treat various conditions.

Depending on the underlying malignancy and how frequently new AKs arise, follow-up patient monitoring 

Modification of Lifestyle 
Disclose sun-safe practices.
- Avoid doing anything outdoors between 10 AM and 4 PM.
- Don protective gear, including a hat with a wide brim.
– Teach self-examination of skin (for melanoma, squamous cell, and basal cell) and the proper use (including reapplication) of sunscreens with SPF >30, preferably a preparation with broad-spectrum (UV-A and UV-B) protection.


Very positive prognosis. Regression rates of 20–30% per lesion every year are possible for a sizable fraction of the lesions.

Complications 
AKs are precancerous lesions that can develop into SCCs.
Uncertainty surrounds the rate of malignant transformation; reported percentages range from 0.1% to a few% per lesion each year.
Patients who have AKs are more likely to develop other cutaneous cancers, and an AK precursor is thought to be responsible for about 60% of SCC cases.

---