Stretch marks result from skin stretching out a lot over a short period of time. All three layers of skin, including the epidermis and dermis, stretch. The dermis layer is below the epidermis, which is the topmost layer of skin. The dermis is far less elastic than the epidermis, and when skin is stretched too far, the dermis tears. Stretch marks are actually tears in the dermis layer.
When the dermis tears, nerves can also be harmed. After the dermis tears, the body will begin to heal it. This healing can take several years. As the skin heals, the damaged nerves are stimulated. When these nerves are stimulated, they cause an itchy sensation. Because healing can take such a long time, the itchiness that accompanies mending nerves can also last long after the stretch marks were formed. Other factors can also stimulate these healing nerves, such as exercise that stretches and pulls at the skin and dryness.
When your skin dries out, the skin over stretch marks might become itchy. While topical treatments such as moisturizing lotions can help, keeping your whole body hydrated is the most effective way to ensure your skin stays dry. In general, people need about eight glasses of water, but much of the water a person needs is consumed through food and other beverages, which also counts into that essential total.
Stretch marks can be itchy even after pregnancy. In fact, many women's stretch marks don't itch until after they have had their babies. Women can develop rashes or skin conditions as a result of having their skin stretched during the latter part of their pregnancy. They can develop a rash called pruritic urticarial papules (also known as polymorphic eruption of pregnancy and plaques of pregnancy). This rash can spread to other parts of the body, but it usually clears up in about a week. They can also develop a skin condition called prurigo of pregnancy (also known as prurigo gestationis). Prurigo of pregnancy can also be genetic. On rare occasions, post-pregnant women can offer suffer from pemphigoid gestationis (also known as herpes gestationis even though it is not related to the herpes viral infection). This is a rare autoimmune disorder in which antibodies attach to certain tissue cells and attack them, making the skin itchy.