What is Actinic Keratosis?

The process of keratin formation in the stratum corneum is called keratinization. It is a process that converts cellular proteins into keratin with completely different physical and chemical properties. The keratinization process includes fibrillary changes in the cytoplasm and the breakdown and disappearance of the cytoplasm and nuclei. Actinic keratosis (actinic keratosis) is a disease mainly caused by hyperkeratosis caused by long-term sunlight or ionizing radiation. It is also called solar keratosis or senile keratosis. It is the most common type of epithelial precancerous skin lesions. It is more common in middle-aged men and more exposed areas. The clinical manifestations are brown red or yellow flat papules or plaques. A few can turn into squamous cell carcinoma, but metastasis is extremely rare. Individuals can be treated with local medicine or physical therapy. If malignancy is suspected, early surgical resection should be performed.

Actinic keratosis

Actinic keratosis is an occupational disease, which is mainly caused by sunlight, ultraviolet rays, radioactive thermal energy, and asphalt or coal and its products. Lesions are more common in sun-exposed areas of middle-aged and older men, such as the face, auricles, and back of hands. It is mainly characterized by rough surface and keratinizing scales. After removing the scales, you can see that the basal surface below is rosy, uneven, and papillary. Treatment usually involves topical medication and surgery. 20% can develop squamous cell carcinoma.

Introduction to Actinic Keratosis

Causes of actinic keratosis

Sunlight, ultraviolet light, radioactive thermal energy, and asphalt or coal and its extracts can all induce the disease, and the patient's susceptibility plays a decisive role.

Pathogenesis of actinic keratosis

Histopathology can be divided into three types: hypertrophic atrophic carcinoma in situ type. Hypertrophic type: Excessive keratinization in the middle epidermis, incomplete keratinization, and spinal layer cell disorder between the hypertrophy and atrophy of the spinous layer, and vacuolar degeneration. Mitosis is more common but atypical cells are not typical. Epidermal atrophy: Atypical cells and slack keratinocytes can be seen in the basal layer. Carcinoma in situ type: thickening of the middle epidermis, disordered arrangement of epidermal cells and atypical cells, and clear boundary between epidermis and dermis. The superficial layer of type 3 dermis has obvious elastic degeneration, with moderate density infiltration, mainly lymphocytes.

Clinical manifestations of actinic keratosis

1. The susceptible and predisposed lesions are more common in sun-exposed parts of middle-aged men and above, such as the face, auricles, and back of hands. Skin lesions can occur in male patients with baldness, auricles, and lower lip. Females are more common in the forearm extension.

2. The clinical symptom damage is limited to brownish red or yellow spots or plaques, with clear borders, ranging from the tip of the needle to more than 2cm in diameter, most of which are uncertain in number of millimeters. Can be slightly higher than the leather surface, but without obvious rising edges. The surface is rough with keratinizing scales. Remove the scales forcibly, and you can see that the basal surface below is ruddy, uneven, and papillary. Sometimes the skin lesions can show horn-like protrusions, and the formation of skin keratosis develops slowly without conscious symptoms. Capillary dilation can occur around the lesion.

Complications: Squamous cell carcinoma is secondary to 20%. Lesions with inflammation, erosion, and ulcers are signs of secondary squamous cell carcinoma.

Diagnosis of actinic keratosis

According to clinical manifestations, it is generally not difficult to diagnose. Pathological examination is required to confirm the diagnosis. Differential diagnosis:

1. Seborrheic keratosis has greasy scales on its surface, soft and smooth stratum corneum, and epidermal cysts are formed in the epidermis.

2. Discoid lupus erythematosus has dilated hair follicle pores and hair follicle horn plugs, and has atrophy and skin lesions. The face, especially the cheeks and nose, are distributed in a butterfly shape.

3. Malignant freckle-like nevus occurs in the exposed area, and is a pigmented spot. It can be enlarged gradually if it is not higher than the skin. The diameter can reach several centimeters. It is brown or black. About 1/3 of the elderly can develop malignant melanin. tumor.

4. Attention should also be paid to the identification of linear epidermal nevus and squamous cell carcinoma.

Actinic keratosis treatment

Actinic keratosis This disease may be transformed into skin cancer, so it should be treated early.

1. Systemic treatment of multiple lesions can be taken orally with B-cis-retinoic acid or etretinate, 0.5-1.0 mg / (kg · d)

2. Topical drug treatment

(1) Aminobenzoic acid preparation: 5ml of aminobenzoic acid, 10ml of glycerol in 60ml of ethanol, and water to 100ml to make an aminobenzoic acid coating agent, once per day.

(2) Anti-tumor drugs: For those who are prevalent or adopt anti-tumor drugs such as 20% podophyllum, 5% fluorouracil or 10% fluorouracil propylene glycol, etc., follow-up should be followed regularly to observe whether there is recurrence. It has also been reported that 1% fluorouracil solution is applied topically, and then 5% triamcinolone cream can obviously reduce side effects such as pain and inflammation. Or adding a small amount of steroid solution to 1% fluorouracil can also achieve the same effect.

(3) Applying 10.5% retinoic acid ointment or using it in combination with 5% fluorouracil ointment is effective for refractory skin lesions.

3. Chinese medicine treatment

(1) Crystal paste rubbing: The so-called crystal paste is made by grinding 15g of ore lime into fine powder and soaking it with concentrated alkali water (about 100m1). The alkali water is 2 fingers higher than the lime surface. Take 50 sticky rice and sprinkle it on the ash. Soak for 1 day and night, remove the rice and mash it into a paste. Once every 2 days in winter. The crystal cream is applied to the skin lesions, so as not to hurt the normal skin, it can be cured after exfoliation.

(2) Depigmentation or black extract stick therapy: apply the extract to the skin lesion after heating and softening. After 3 to 5 days, the extract is removed and the softened keratin is scraped off with a blunt knife. If it does not heal, repeat the application until the skin lesions disappear. You can also use 5-fluorouracil cream after skin lesions become thinner, the effect is better.

4. Physical therapy carbon dioxide laser method, electrocautery method, and liquid nitrogen freezing method can quickly remove skin lesions and have fewer adverse reactions.

5. Surgical resection 6.X-ray irradiation treatment can be performed for skin lesions suspected of being cancerous or existing cancerous.

Prognosis prevention of actinic keratosis

Prognosis: Squamous cell carcinoma is secondary to 20%. It is generally believed that squamous cell carcinoma with actinic keratosis is non-erosive, rarely metastasize, and has a good prognosis.

Prevention: The occurrence of this disease is closely related to sunlight exposure, especially medium-wave ultraviolet (spectrum 280-320nm). Therefore, those who work outdoors or often go out, it is best to rub sunscreen on the skin of the exposed area, such as 5% titanium dioxide ointment 5% para-aminobenzoic acid cream and sunscreen. You can also parachute or wear a sun hat when going out.