Introduction

Introduction to sun keratosis

Solar keratosis (solarkeratosis), also known as senile keratosis, is more common in men than middle-aged. It mainly occurs in the exposed area, the skin lesions are brown keratotic patches, and the surface is covered with dark brown scales that are not easily peeled off. Often single. The course of the disease is chronic. If the lesion rapidly expands into a sickle or nodular shape, or even ulceration, it suggests the possibility of worsening squamous cell carcinoma. Sun keratosis is a precancerous lesion caused by long-term sun exposure and skin damage, and is prone to occur in middle-aged and elderly patients with fair skin. The damage begins with a pale red flat papule with scaly and crusted surface. It can be pigmented for a long time, the surface is dry and the keratinization is remarkable. Usually distributed in the face, ears, back of the hand and forearm and other areas often exposed to the sun, some cases can become squamous cell carcinoma.

basic knowledge

The proportion of illness: 0.002%

Susceptible people: more common in middle-aged men

Mode of infection: non-infectious

Complications: squamous cell carcinoma

Pathogen

Causes of sun keratosis

Cause:

Sunlight keratosis, commonly known as senile keratosis, is a precancerous lesion caused by long-term sun exposure and skin damage, and is prone to occur in middle-aged and elderly patients with fair skin. The damage begins with a pale red flat papule with scaly and crusted surface. It can be pigmented for a long time, the surface is dry and the keratinization is remarkable. Usually distributed in the face, ears, back of the hand and forearm and other areas often exposed to the sun, some cases can become squamous cell carcinoma.

Prevention

Solar keratosis prevention

When you go out on a hot day, you need to do a good job of skin masking and sun protection, minimize UV radiation, and avoid contact with toxic substances.

1. It is especially important to avoid sun exposure, especially during the summer from 10 am to 3 pm.

2. Apply some sunscreens to protect the skin. Care should be taken to use sunscreens that are effective, stable, and durable, not easy to be washed by sweat, non-toxic, and non-irritating.

3. The topical application of retinoids has a good effect on the disease and skin aging.

4. Reasonable diet, diet should be light, avoid spicy spicy food.

Complication

Solar keratosis complications Complications squamous cell carcinoma

Untreated, about 20% of patients can develop squamous cell carcinoma, but usually does not metastasize.

Symptom

Symptoms of sun keratosis common symptoms epidermal keratin papules blush

Skin lesions are red to pale brown or grayish white round, irregularly shaped keratinized papules, clear boundary, surface adhesion thickness and range of dry adhesive scaly, not easy to peel off, surrounded by redness, occasionally obvious hyperkeratosis of skin lesions Form a leather corner. They vary in size from one or a few millimeters to 1 cm or more. The site of skin lesions usually has obvious sun damage, which is characterized by dryness, shrinkage, atrophy and telangiectasia, and is often accompanied by senile freckles.

Occurs in the exposed parts, the face, lower lip, back of the hand, forearm, neck, head and baldness are more common, the skin lesions are multiple, and there are also single. No symptoms or itching.

One or more lesions in about 20% of patients without treatment can progress to squamous cell carcinoma, but usually no metastasis occurs; the metastatic rate ranges from 0.5% to 3%.

Examine

Examination of sun keratosis

Histopathology

Extensive hyperkeratosis of the epidermis with obvious parakeratosis in the boundary, where the epidermal cells are disorderly arranged, the nucleus is irregular in shape, large and deep, and nuclear fission is observed. The basal cells are atypical bud-like hyperplasia and extend to the upper part of the dermis; Significant elastic fiber degeneration, and often more lymphocytic infiltration. The abnormal epidermis and the collar near the normal epidermis alternate and exist, and the boundary is clearly characterized by histopathology.

Diagnosis

Diagnosis and identification of solar keratosis

diagnosis

1. Mainly occurs in older men.

2. The incidence is related to long-term sun exposure, and the exposed parts such as face and back are more common.

3. The lesion is a hyperkeratotic plaque of the size of soybean to broad bean. It is near normal normal skin color, and then gradually dark brown, with mild redness around, rough surface and sticky scales.

4. The disease develops slowly, generally no symptoms, about 20% cancer.

5. Histopathology: 1 is a precancerous lesion, showing disordered cell arrangement, a few cells have atypical; 2 is divided into three types: hypertrophic, atrophic and intraepithelial carcinoma; 3 upper collagen is alkalophilic, dense Lymphocyte-based inflammatory infiltration.

Differential diagnosis

Seborrheic keratosis is oily, brown to dark brown flat papules, which are easily scraped off, while solar keratinized skin lesions are rough-faced papules or maculopapular rash, which is sticky and difficult to scrape off. Solar keratosis is a precancerous lesion, and seborrheic keratosis is rarely cancerous.

The clinical manifestations of arsenic keratosis are similar to those of sun keratosis, but they are more frequent and severe, most common in palms and athlete's feet. They have long-term use or injection, long-term exposure to pentavalent arsenic, and may be accompanied by excessive pigmentation caused by arsenic. .