Stretch marks

Stretch Marks (Striae Distensae)

Stretch marks, medically known as striae distensae, are a common dermatological concern characterized by linear, scar-like lesions that form when the skin undergoes rapid stretching. They often appear as reddish or purplish streaks initially, later fading into white or silvery lines. While stretch marks are not medically harmful, they can cause cosmetic distress and may be associated with underlying medical or physiological conditions.

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Causes and Risk Factors

Stretch marks form due to a combination of mechanical stretching of the skin and hormonal influences that reduce dermal elasticity. The dermis tears microscopically, leading to the appearance of these streaks.

Common causes include:

• Pregnancy (striae gravidarum): Most common in the second and third trimesters due to rapid abdominal expansion and hormonal changes.

• Adolescence: Growth spurts during puberty can trigger stretch marks on the thighs, buttocks, breasts, or back.

• Obesity or rapid weight gain: Increases skin stretching and collagen disruption.

• Corticosteroid use: Long-term topical or systemic steroid therapy weakens collagen and connective tissue.

• Endocrine disorders: Conditions such as Cushing’s syndrome, Marfan syndrome, and other connective tissue disorders predispose individuals to stretch marks.

• Genetic factors: Family history plays a role in susceptibility.

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Appearance and Stages

Stretch marks typically evolve through two stages:

1. Striae rubrae (early stage):

   • Red, purple, or pink in color due to vascular dilation.

   • Slightly raised and may feel itchy or irritated.

2. Striae albae (late stage):

   • Pale, white, or silvery in color as vascularity diminishes.

   • Become depressed, atrophic, and less responsive to treatments.

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Diagnosis

Diagnosis is usually clinical, based on history and physical examination.

• Medical history should assess underlying risk factors such as corticosteroid use, endocrine disorders, pregnancy, or rapid weight changes.

• In atypical cases or when associated with systemic symptoms (e.g., unexplained weight gain, hypertension, or menstrual irregularities), further evaluation for Cushing’s syndrome or other endocrinopathies may be required.

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Management and Treatment

Stretch marks are not completely preventable or curable, but multiple treatment options can improve their appearance. Management depends on the stage (rubrae vs albae) and patient preference.

1. Topical Therapies

• Tretinoin (Retinoic Acid):

  • Mechanism: Stimulates collagen production and improves epidermal thickness.

  • Dose: Topical 0.025–0.1% cream, applied once daily at night.

  • Limitations: Works best for early (striae rubrae) marks; contraindicated in pregnancy due to teratogenic risk.

• Hyaluronic Acid Creams:

  • Improves skin hydration and elasticity, showing benefit in reducing early stretch marks.

• Centella asiatica Extract:

  • Herbal extract used in creams that stimulates fibroblast activity and collagen production.

• Cocoa Butter, Shea Butter, Vitamin E Creams:

  • Widely used as moisturizers, though clinical evidence supporting efficacy is limited.

• Corticosteroid Creams:

  • Generally avoided as they may worsen striae by thinning skin further.

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2. Laser and Light-Based Therapies

• Pulsed Dye Laser (PDL):

  • Targets vascular component, reducing redness in early striae.

• Fractional CO₂ Laser and Er:YAG Laser:

  • Stimulate dermal remodeling and collagen synthesis, effective in striae albae.

• Excimer Laser (308 nm):

  • Increases pigmentation in white stretch marks, making them less visible.

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3. Microdermabrasion

• A non-invasive resurfacing procedure that improves skin texture and stimulates new collagen formation. Works better for striae rubrae than albae.

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4. Microneedling (Collagen Induction Therapy)

• Involves puncturing the skin with fine needles to stimulate collagen and elastin production.

• Often combined with platelet-rich plasma (PRP) or topical retinoids for enhanced results.

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5. Chemical Peels

• Agents such as glycolic acid (20–70%) are applied to exfoliate and stimulate new skin growth.

• Mild to moderate efficacy in improving striae appearance.

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6. Radiofrequency Therapy

• Uses heat energy to stimulate dermal collagen synthesis.

• Can be combined with microneedling or fractional lasers for synergistic results.

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7. Prevention

• Moisturization: Maintaining skin hydration may help improve elasticity, though evidence is mixed.

• Controlled weight gain: Particularly during pregnancy, gradual weight increase reduces skin stress.

• Avoiding prolonged corticosteroid use: Unless medically necessary.

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Pharmacological and Supportive Treatment Options

• Tretinoin cream 0.025–0.1% once daily (not in pregnancy).

• Moisturizers containing hyaluronic acid or Centella asiatica, applied twice daily.

• Oral antioxidants (Vitamin C, E, Zinc) may support skin repair but have limited direct evidence.

• Pain or itching: Managed with mild topical emollients or antihistamines if required.

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Prognosis

• Stretch marks typically fade over time, becoming less noticeable, but rarely disappear completely.

• Early treatment during the striae rubrae stage offers the best chance of improvement.

• Chronic white striae (striae albae) are more resistant but can still improve with laser, microneedling, and combined therapies.

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Key Notes for Clinical Practice

• Cosmetic concern is the main reason patients seek treatment.

• Complete eradication is rarely possible—setting realistic expectations is crucial.

• Combination therapy (topical + laser/microneedling/peels) often yields the best results.

• Always assess for underlying causes (pregnancy, endocrine disorders, steroids) to address root contributors.