What causes flat warts? HPV causes them

Flat warts are caused by HPV. Papules will appear at the affected area. Generally, there are no obvious symptoms. Some may experience mild itching, which is especially common on the face. Some people cannot recover from flat warts for several years, so it is necessary to find appropriate treatment methods in time.

1. Causes:

Caused by HPV 3, 5, 8, 9, 10, 28, 41, and 65, HPV is transmitted through direct or indirect contact to the host's skin and mucosal epithelial cells, enters the cells through contact with tiny erosions, stays in the nuclei of epithelial cells at the infected site, replicates and transcribes, but does not enter the blood circulation and does not produce viremia.

2. Common symptoms

1. Generally there are no subjective symptoms, but there may be slight itching occasionally.

2. The skin lesions are flat and smooth papules ranging from cap-needle shaped to mung bean-shaped or slightly larger, round, oval or polygonal, hard in texture, and of normal skin color or light brown.

3. It often occurs on the face, back of hands and forearms.

The onset is sudden, with more lesions than normal skin, often scattered or densely distributed. Due to scratching, the lesions may be autoinoculated and arranged in a beaded manner along the scratches. The course of the disease is chronic and may resolve on its own. Scratching is obvious before resolution, and no trace is left after healing.

It is common in children and adolescents, and also in adults. It often occurs symmetrically on the face (cheeks, temples, forehead, chin), back of hands and forearms, and appears as round, oval or irregular flat papules of normal skin color or light brown, ranging in size from a pinhead to a lentil. The surface is smooth and hard, and they may be scattered or dense, or fused into small flakes. They may be arranged in a beaded pattern due to scratches (isomorphic reaction) (Figures 1-3). There are no subjective symptoms, and itching often occurs before it subsides. Traditional Chinese medicine calls it "flat warts", which are caused by disharmony of qi and blood, loose pores, and external pathogens, which condense on the skin. The disease progresses slowly and may last for 3 to 4 years without recovery. It is self-limiting and can recover on its own in 1 to 2 years.