Violeceous stretch marks

Specialty: Endocrine and metabolic.

• purple stretch marks
• wide Cushing's cutaneous striae
• striae rubrae distensae

Why it occurs

• Endogenous Cushing's syndrome (chronic hypercortisolism directly inhibits the metabolic activity of dermal fibroblasts, preventing the proper synthesis of collagen and elastin, resulting in extreme dermal thinning that reveals the underlying dermal blood vessels)
• Topical use of high potency glucocorticoids under occlusion or prolonged chronic systemic use
• Puberty with rapid longitudinal growth or accelerated weight gain (physiological variant where mechanical stretching exceeds dermal elasticity, although they are usually thin and pink)
• Marfan syndrome or Ehlers-Danlos syndrome (inherited connective tissue disorders characterized by intrinsic structural defects of collagen or fibrillin)

Initial workup

Two independent determinations of 24-hour urinary free cortisol; nocturnal salivary cortisol at 11:00 p.m.; determination of plasma ACTH; complete blood count and fasting plasma glucose and HbA1c levels; ultrasound of the adrenal glands or abdominal computed tomography depending on the orientation of the hormonal axis.

Standard management

• Ketoconazole — as an inhibitor of adrenal cortisol synthesis to stop collagen damage at the dermal level in Cushing's
• Tretinoin cream 0.1% — applied topically at night to induce the synthesis of new collagen in early stretch marks, effective only if the underlying hypercortisolism is controlled
• Zinc chloride — oral supplementation to support dermal collagen synthesis
• Mupirocin 2% cream — topical antibiotic to treat secondary skin infections that occur on eroded stretch marks