Why does hair become curly after chemotherapy?

Chemotherapy-Induced Curly Hair: Mechanisms and Management

Chemotherapy-induced curly hair occurs due to damage to hair follicle stem cells and matrix cells, causing altered hair shaft formation when regrowth begins after treatment. This phenomenon represents one of several changes to hair that can occur following cancer treatment.

Mechanism of Chemotherapy-Induced Hair Changes

Chemotherapy primarily affects rapidly dividing cells, including those in the hair follicle matrix. The process involves:

1. Initial damage phase:

   • Chemotherapy drugs target rapidly dividing matrix cells in the hair follicle
   • This causes anagen effluvium (active growth phase hair loss) 1
   • Approximately 65% of patients receiving classic chemotherapy experience hair loss 2, 3

2. Recovery and regrowth phase:

   • Damage to hair follicle stem cells alters their differentiation pattern
   • When hair regrowth begins, the follicle produces hair with different structural characteristics
   • The altered hair shaft formation results in different texture, often curly or wavy, compared to pre-treatment hair

Types of Hair Changes After Chemotherapy

The NCCN guidelines note several changes that can occur with hair regrowth after chemotherapy 4:

• Curly or wavy texture (when hair was previously straight)
• Color changes (often darker or grayer)
• Thickness changes (typically thinner)
• Altered growth rate (usually slower)

These changes may be temporary or permanent, depending on the specific chemotherapy regimen and individual factors.

Risk Factors for Permanent Hair Changes

Some chemotherapy regimens are associated with higher risk of permanent hair changes:

• High-risk agents:

  • Taxanes (especially docetaxel) 5
  • Busulfan 5
  • Platinum agents (cisplatin) 5
  • High-dose cyclophosphamide 4

• Patient factors:

  • Age (older patients have higher risk)
  • Cumulative drug dose
  • Combination chemotherapy regimens

Management Strategies

Prevention:

1. Scalp cooling during chemotherapy:

   • The NCCN guidelines recommend considering scalp cooling to reduce chemotherapy-induced alopecia 4
   • Response rates range from 50-80% 3
   • May be less effective with anthracycline-containing regimens 4

2. Pharmacological approaches:

   • Currently no FDA-approved medications specifically for prevention
   • Topical minoxidil may reduce severity or duration but does not prevent hair loss 2
   • Research is exploring selective enhancement of ATP-binding cassette transporters in hair follicles to reduce drug accumulation 6

Management of Post-Chemotherapy Hair Changes:

1. Hair care practices:

   • Gentle hair care with mild shampoos
   • Avoid excessive heat styling or chemical treatments
   • Use wide-toothed combs to prevent breakage

2. Cosmetic approaches:

   • Temporary use of wigs, scarves, or hats during regrowth phase
   • Styling products designed for curly hair may help manage new texture

3. Medical interventions:

   • For those with permanent hair changes resembling androgenetic alopecia, standard treatments for pattern hair loss may be considered 5
   • Regular follow-up to monitor for improvement or stabilization

Prognosis

The prognosis for chemotherapy-induced hair changes varies:

• Most patients experience complete hair regrowth within 3-6 months after completing chemotherapy
• Approximately 65% will notice texture changes, including curliness 2
• A subset of patients may experience permanent changes in hair texture, density, or growth rate 5
• Some patients may show changes in color and/or texture of regrown hair, and in limited cases, the reduction in density may persist 2

Clinical Implications

Healthcare providers should counsel patients about potential hair changes before beginning chemotherapy. This preparation helps manage expectations and reduce psychological distress associated with altered appearance during cancer treatment and recovery.

Understanding that curly hair after chemotherapy represents altered hair follicle function rather than a new medical concern can help reassure patients that this is a recognized phenomenon following cancer treatment.