Removal of 140 seborrheic keratosis with Cryotherapy in Jan & April. What causes them?

Hello avon1577.  Lets talk about seborrheic keratoses.  Seborrheic keratoses are on of the most common skin growths in older adults.  They are noncancerous.  They usually look like a mounded back,brown or tan growth with a waxy, scaly kind of appearance.  most common locations are the face, chest, shoulders or back.  We think they are related to sun exposure and they can look like skin cancer, but they do not become cancerous.  Normally they cause no pain but people often have them removed for appearance purposes.  They come in a wide range of sizes and may itch as well.  It is best not to pick, rub or scratch them off.  This will cause bleeding.  Rarely, this can cause infection as well.  They are not contagious.  They tend to be more common in families so it is possible that there is a genetic predisposition as well.  We do not know the exact cause of these lesions so it is difficult to say if there really are any good preventative options.  Options for removal include freezing with liquid nitrogen.  Sometimes this does not work if the growth is raised and could even lighten the skin.  Another option is scraping the lesion with curettage if the lesion is not as raised or even flat.  Another option is burning with electrocautery.  This option can lead to scarring if not done properly and may take longer to heal than other options.  A final option is laser ablation.  Unfortunately, if you have had skin color changes after removal, it may be permanent depending on the method used.