Solar lentigo

Introduction to solar freckle Solar freckle-like nevus (solarfreckle-likenevus) refers to pigmented spots with clear boundaries caused by natural or artificial ultraviolet radiation. It is more common in middle-aged people over 50 years old, also known as senile freckles. basic knowledge The proportion of illness: 0.005% Susceptible people: more common in middle-aged people over 50 years old Mode of infection: non-infectious Complications: pigmentation spots

Sunlight freckle-like cause

(1) Causes of the disease

It is related to degenerative skin and light in the elderly.

(two) pathogenesis

Under light microscopy, the epidermal process of the diseased tissue is obviously elongated, showing a scorpion or bud shape, often branching and merging, and the epidermis between the epidermis becomes thin or atrophy, and the number of epidermal melanocytes increases. The Dopa response increases, and the blood vessels around the dermis A small amount of monocyte infiltration was observed, and melanocytes were mixed. Under electron microscope, the keratin cells in the lesions were rich in melanosomes, which were generally larger than the melanosomes in the adjacent skin keratinocytes.

The melanocytes in the lesions have increased melanocyte activity in the non-illuminated skin, showing increased reactivity to Dopa, dendritic mutations, increased morphine in normal morphology, increased perinuclear body, and well-developed Rough endoplasmic reticulum, a large number of mitochondria and hyperplastic Golgi complexes.

Solar freckle-like prevention

Prevent sun exposure for a long time.

Solar freckle-like complications Complications

Light brown spotted macules with light brown pigmentation spots.

Sunlight freckle-like symptoms common symptoms freckle pigmented macule skin more sunburn

1. Good hair

Frequently exposed to ultraviolet radiation on the face and forearms, especially the back of the hand.

2. Dark brown rash

The boundary is relatively clear, the diameter is mostly less than 5mm, and it can reach the size of the walnut, scattered and sometimes merged into pieces.

3. Spot change

As the ageing pigmentation spots increase and expand, the color will deepen, and very few patients will develop malignant transformation, called malignant senile lentigo.

Sunlight freckle-like examination

Histopathological examination: It can be seen that the basal cells in the epidermis protrude from the bud, and the melanocytes increase and the melanin particles also increase.

Diagnosis and identification of solar freckles

diagnosis

According to the medical history and clinical features, it is generally not difficult to diagnose, but it needs to be confirmed by pathological examination.

Differential diagnosis

1. Simple freckle-like sputum is more common in children. Histopathology shows that the number of melanocytes in the basal layer of the epidermis increases, and the epidermal process is mild to moderately prolonged.

2. Junction Histopathology shows that the sputum cells are nested and lack dendritic processes.

3. The malignant freckle-like epidermis atrophy, and the atypical melanocytes in the basal layer are non-nested.

4. Solar keratosis lesions have rough surface and keratinized scales. Histopathology shows hyperkeratosis or parakeratosis of the epidermis, and acanthosis and atrophy coexist.

5. The base of pigmented seborrheic keratosis does not grow downward, the borders on both sides are clear, and squamous cells and basal-like cells can be seen in the hyperplastic epidermis.

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