Stretch marks, also known as striae () or striae distensae, are a form of

scar A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a ...

ring on the

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

with an off-color hue. Over time they may diminish, but will not disappear completely. Striae are caused by tearing of the

dermis The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided ...

during periods of rapid growth of the body, such as during

puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a ...

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

, in which they usually form during the last trimester. Usually on the stomach, these striae also commonly occur on the breasts, thighs, hips, lower back, and buttocks. Pregnancy-related striae are known as ''striae gravidarum''. Striae may also be influenced by the

hormonal A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required f ...

changes associated with puberty, pregnancy,

bodybuilding Bodybuilding is the use of progressive resistance exercise to control and develop one's muscles (muscle building) by muscle hypertrophy for aesthetic purposes. It is distinct from similar activities such as powerlifting because it focuses ...

, or hormone replacement therapy. There is no evidence that creams used during pregnancy prevent stretch marks. Once they have formed there is no clearly effective treatment, though various methods have been attempted and studied.

Signs and symptoms

Striae, or "stretch marks", begin as reddish or purple

lesions A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classifi ...

, which can appear anywhere on the body, but are most likely to appear in places where larger amounts of fat are stored; the most common places are the

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...

(especially near the

navel The navel (clinically known as the umbilicus, commonly known as the belly button or tummy button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. All placental mammals have a navel, altho ...

), breasts, upper arms, underarms, back, thighs (both inner and outer), hips, and buttocks. Over time, they tend to

atrophy Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply ...

and lose pigmentation. The affected areas appear empty, and are soft to the touch. Stretch marks occur in the

, the resilient middle tissue layer that helps the

retain its shape. No stretch marks will form as long as there is support within the dermis; stretching plays a role in where the marks occur and in what direction they run, however, there are a number of contributing factors (see: "Causes", below) to their formation. They can (but do not always) cause a burning and itching sensation, as well as emotional distress. They pose no health risk in and of themselves, and do not compromise the body's ability to function normally and repair itself, however, they are often considered a cosmetic nuisance. Young women are generally affected the most and often seek treatment for them from a dermatologist and following

. File:Squircle belly (19004951).jpg, Striae gravidarum in a pregnant woman at 38 weeks File:Female Torso with Tiger Stripes (Stretch Marks) from Pregnancy.JPG, Stretch marks from pregnancy >1 year postpartum File:StretchMark.jpg, Normal stretch marks in a teenage male File:Stretch marks on female breast.jpg, Stretch marks in a female breast File:Central Obesity 008.jpg, Striae distensae on an obese male

Causes

Stretch marks appear to be caused by stretching of the skin. This is especially true when there is an increase in

cortisone Cortisone is a pregnene (21-carbon) steroid hormone. It is a naturally-occurring corticosteroid metabolite that is also used as a pharmaceutical prodrug; it is not synthesized in the adrenal glands. Cortisol is converted by the action of the enz ...

an increase in cortisone levels can increase the probability or severity of stretch marks by reducing the skin's pliability. More specifically, it affects the

by preventing the

fibroblast A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells ...

s from forming

collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whol ...

and

elastin Elastin is a protein that in humans is encoded by the ''ELN'' gene. Elastin is a key component of the extracellular matrix in gnathostomes (jawed vertebrates). It is highly elastic and present in connective tissue allowing many tissues in the bo ...

fibers necessary to keep rapidly growing skin taut; this can create a lack of supportive material as the skin is stretched, and lead to dermal and epidermal tearing, which in turn can produce scarring in the form of stretch marks. This is particularly the case when there is new tissue growth (which can interfere with the underlying physical support of the dermis or epidermis, by displacing the supportive tissue). Examples of cases where stretch marks are common, also given by the Mayo Clinic, include weight gain (in the form of fat and/or

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of mus ...

, and adolescent growth spurts, though it is also noted that some medications, as well as other medical conditions and diseases, may increase the likelihood of stretch marks appearing. In the case of medication, the Clinic points to "

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are inv ...

creams, lotions and pills and chronic use of oral or systemic

steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and ...

s" as a common contributing factor. Medical conditions that can contribute to stretch marks include Ehlers-Danlos syndrome, Cushing's syndrome,

Marfan syndrome Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those with the condition tend to be tall and thin, with long arms, legs, fingers, and toes. They also typically have exceptionally flexible joints a ...

, and "adrenal gland diseases".

Pregnancy

Pregnancy stretch marks, also known as ''striae gravidarum'', are a specific form of scarring of the skin of the abdominal area due to rapid expansion of the

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...

as well as sudden weight gain during pregnancy. About 90% of pregnant women are affected. A number of additional factors appear to promote the appearance of stretchmarks: one study of 324 women, done just after they had given birth, demonstrated that low maternal age, high body mass index, weight gain over 15 kg (33 pounds) and higher neonatal birth weight were independently correlated with the occurrence of striae. Teenagers were found to be at the highest risk of developing severe striae. These skin marks are symptoms of pregnancy caused by the tearing of the

, resulting in

and loss of

rete ridges Rete pegs (also known as rete processes or rete ridges) are the epithelial extensions that project into the underlying connective tissue in both skin and mucous membranes. In the epithelium of the mouth, the attached gingiva exhibit rete pegs, wh ...

. These scars often appear as reddish or bluish streaks on the abdomen, and can also appear on the breasts and thighs. Some of these striae disappear with time, while others remain as permanent discolorations of the body. Mechanical distension and rapidly developing areas of the body during pregnancy (such as the abdomen, breasts, and thighs) are most commonly associated with striae formation. Some have suggested that

relaxin Relaxin is a protein hormone of about 6000 Da first described in 1926 by Frederick Hisaw. The relaxin family peptide hormones belong to the insulin superfamily and consists of seven peptides of high structural but low sequence similarity; re ...

and

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

combined with higher levels of

cortisol Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the '' zona fasciculata'' of the adrenal cortex in the adrenal g ...

during pregnancy can cause an accumulation of mucopolysaccharides, which increases water absorption of

connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...

, making it prime for tearing under mechanical stress. There also seems to be an association between higher body mass indices and in women with bigger babies and the incidence and severity of striae. Also, younger women seem to be at higher risk of developing striae during pregnancy. The prevalence and severity of striae gravidarum varies among populations. The current literature suggest that in the general population of the US, there is a 50%-90% prevalence of striae associated with pregnancy, partly as a result of the normal hormonal changes of pregnancy and partly due to stretching of skin fibers. Many women experience striae gravidarum during their first pregnancy. Nearly 45% percent of women develop striae gravidarum before 24 weeks of gestation. Many women who develop lesions during the first pregnancy do not develop them during later pregnancies. Genetic factors such as

genealogy Genealogy () is the study of families, family history, and the tracing of their lineages. Genealogists use oral interviews, historical records, genetic analysis, and other records to obtain information about a family and to demonstrate kin ...

and race also seem to be predictive in the appearance of striae.

Prevention

Collagen and elastin are proteins in the skin that contribute to the skin's strength, resilience, flexibility, and help skin that has been stretched to recover its original state. Boosting the production of collagen and elastin helps prevent stretch marks from occurring. Stretch marks can also derive from nutritional deficiencies. Consuming foods that contribute to the skin's health, such as zinc-rich foods, foods high in vitamin A, C, D, and protein rich foods, can help suppress stretch marks. A systematic review has not found evidence that creams and oils are useful for preventing or reducing stretch marks in pregnancy. The safety in pregnancy of one ingredient, '' Centella asiatica'', has been questioned. Evidence on treatments for reducing the appearance of the scars after pregnancy is limited.

Treatment

There are no clearly useful treatments for stretch marks, although there are many different suggestions on how to remove them or lessen their appearance. Various efforts that have been tried including laser treatments,

glycolic acid Glycolic acid (or hydroxyacetic acid; chemical formula HOCH2CO2H) is a colorless, odorless and hygroscopic crystalline solid, highly soluble in water. It is used in various skin-care products. Glycolic acid is widespread in nature. A glycolate (s ...

, and microdermabrasion.

Tretinoin Tretinoin, also known as all-''trans'' retinoic acid (ATRA), is a medication used for the treatment of acne and acute promyelocytic leukemia. For acne, it is applied to the skin as a cream, gel or ointment. For leukemia, it is taken by mouth f ...

(0.1% w/w), which is a

retinoid The retinoids are a class of chemical compounds that are vitamers of vitamin A or are chemically related to it. Retinoids have found use in medicine where they regulate epithelial cell growth. Retinoids have many important functions throughout ...

, has found to be effective on early stretch marks in several studies. Hyaluronic acid also improves the appearance of stretch marks. Topical tretinoin is categorized by the FDA as a known teratogen (causing malformations in fetuses) in animals, without adequate human studies on safety in pregnancy. Carboxytherapy is a known procedure; however, there is a lack of evidence to support how effective it is.

History

Since ancient times, pregnant women have sought remedies to prevent stretch marks during pregnancy. Both ancient

Greeks The Greeks or Hellenes (; el, Έλληνες, ''Éllines'' ) are an ethnic group and nation indigenous to the Eastern Mediterranean and the Black Sea regions, namely Greece, Cyprus, Albania, Italy, Turkey, Egypt, and, to a lesser extent, ot ...

and Romans used

olive oil Olive oil is a liquid fat obtained from olives (the fruit of ''Olea europaea''; family Oleaceae), a traditional tree crop of the Mediterranean Basin, produced by pressing whole olives and extracting the oil. It is commonly used in cooking: ...

, while

Ethiopians Ethiopians are the native inhabitants of Ethiopia, as well as the global diaspora of Ethiopia. Ethiopians constitute several component ethnic groups, many of which are closely related to ethnic groups in neighboring Eritrea and other parts o ...

and

Somalis The Somalis ( so, Soomaalida 𐒈𐒝𐒑𐒛𐒐𐒘𐒆𐒖, ar, صوماليون) are an ethnic group native to the Horn of Africa who share a common ancestry, culture and history. The Lowland East Cushitic Somali language is the shared ...

used

frankincense Frankincense (also known as olibanum) is an aromatic resin used in incense and perfumes, obtained from trees of the genus '' Boswellia'' in the family Burseraceae. The word is from Old French ('high-quality incense'). There are several species ...

. Striae were first recognized by Roederer in 1773, and were later histologically described by Troisier and Ménétrier in 1889. In 1936, Nardelli made the first morphologically correct descriptions.

Terminology

Medical terminology Medical terminology is a language used to precisely describe the human body including all its components, processes, conditions affecting it, and procedures performed upon it. Medical terminology is used in the field of medicine Medical terminolog ...

for these kinds of markings includes striae atrophicae, vergetures, stria distensae, striae cutis distensae, lineae atrophicae, linea albicante, or simply striae.

References

External links

{{DEFAULTSORT:Stretch Marks Abnormalities of dermal fibrous and elastic tissue Human pregnancy Obstetrics Medical conditions related to obesity Health issues in pregnancy Pregnancy-related cutaneous conditions Pathology of pregnancy, childbirth and the puerperium