Updated: 2/9/2019

Hypertrophic & Keloid Scars

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Snapshot
  • A 50-year-old Caucasian man presents to his dermatologist for a scar that is hindering mobility in his right knee. A few weeks ago, he tripped and fell on a sharp rock, resulting in a 6 cm cut over his knee. Since then, his cut has healed and a raised pink scar has grown over the wound. On physical exam, it is exactly 6 cm without growing beyond the original wound and is pink and shiny. His right knee does not fully extend due to the scar. To prevent further contractures, the physician discuss the possibility of surgical excision. (Hypertrophic scar)
Introduction
  • Clinical definition
    • abnormal and excessive scarring in response to dermal injury, resulting in hypertrophic scars or keloids
  • Epidemiology
    • incidence
      • keloid
        • 6-16% of African population
    • demographics
      • most commonly in ages 10-30
    • risk factors
      • keloid
        • ↑ in groups with darker skin
        • patients of African, Hispanic, or Asian descent
        • family history
        • wounds on chest, shoulders, upper arms, earlobes, or cheeks
      • hypertrophic scar
        • wounds on areas of high skin tension
          • shoulders, neck, knees, ankles
      • both
        • dermal injury caused by burns
        • wounds that take > 3 weeks to heal
  • Etiology
    • keloid
      • previous trauma
      • spontaneous
    • hypertrophic scar
      • previous trauma
  • Pathogenesis
    • dysregulation of wound healing
      • recall normal wound healing stages
        • inflammation, proliferation, and remodeling/maturation
    • keloid
      • ↑↑ type I and type III collagen
        • disorganized and extends beyond the original wound
        • abnormalities in melanocyte stimulating hormone may contribute
    • hypertrophic scar
      • ↑ type III collagen
        • organized as parallel and confined to the original wound
        • increased activation of myofibroblasts may contribute
  • Prognosis
    • keloid
      • recurrence is frequent
      • will not regress over time
    • hypertrophic scar
      • recurrence is rare
      • may regress over time
Presentation
  • Symptoms
    • abnormal scarring occurs after trauma or injury
    • often itchy or painful (keloids > hypertrophic scar)
    • keloid
      • may take months to years to develop
    • hypertrophic scar
      • usually appears within 1 month
  • Physical exam
    • scarring along previous site of wound
    • well-defined, firm, and shiny
    • pink, purple, or hyperpigmented
    • irregular borders
Studies
  • Biopsy 
    • indication
      • only if clinical diagnosis is uncertain
  • Histology
    • keloid
      • thick collagen fibers with abundant mucoid matrix
      • disorganized type I and III collagen
    • hypertrophic scar
      • thin collagen fibers with minimal mucoid matrix
      • myofibroblasts
      • parallel type III collagen
Differential
  • Dermatofibroma protuberans
    • slowly growing, asymptomatic, skin-colored or hyperpigmented plaque with irregular nodularity
    • locally invasive, malignant sarcoma
  • Dermatofibroma  
    • benign, fibroblast proliferation
    • appears as firm, skin-colored or hyperpigmented nodule that may be asymptomatic or pruritic
    • may dimple when pinched
    • does not substantially grow in size
  • Basal cell carcinoma
Treatment
  • Medical
    • intralesional corticosteroid injections
      • indication
        • first-line for treatment that is often used with silicone sheeting
    • silicone sheeting
      • indications
        • first-line for treatment that is often used with intralesional corticosteroid injections
  • Non-operative
    • laser therapy or cryotherapy
      • indication
        • when first-line therapies fail
        • for larger lesions (> 0.5 cm in height)
  • Operative
    • surgical excision
      • indication
        • for scars that are associated with contractures
Complications
  • Contractures limiting mobility associated with hypertrophic scars
 

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Questions (3)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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