When should a scalp biopsy be done?

When Should a Scalp Biopsy Be Done?
Scalp biopsy is a small, outpatient procedure that removes a core of skin and hair follicles for microscopic examination. It can be a vital tool in diagnosing unexplained hair loss, especially when the cause isn't clear from your medical history, physical exam or simple tests. Below is an overview of when a scalp biopsy is most useful, how it’s performed, and what to expect.

---

Why Consider a Scalp Biopsy in Hair Loss?

Hair loss (alopecia) has many causes—genetic, hormonal, inflammatory, infectious or scarring. A scalp biopsy can:

• Confirm or rule out scarring (cicatricial) versus non-scarring hair loss
• Distinguish between similar-looking conditions (for example, early scarring alopecia vs. chronic telogen effluvium)
• Guide targeted treatment by identifying specific inflammatory patterns
• Avoid unnecessary or ineffective therapies when the diagnosis is uncertain

According to dermatopathologist Whiting DA, scalp biopsy adds value in diffuse and focal hair loss when clinical features overlap or when first-line treatments fail.

---

Key Indications for Scalp Biopsy

Consider a scalp biopsy hair loss evaluation when:

• Diagnosis Is Unclear After Initial Workup
 – Negative or inconclusive blood tests (e.g., thyroid function, iron studies)
 – Normal scalp dermoscopy (trichoscopy) but ongoing shedding or thinning
 – A “pull test” that doesn’t pinpoint shedding patterns

• Suspected Scarring (Cicatricial) Alopecia
 – Areas of permanent hair loss with smooth, shiny skin
 – Complaints of burning, itching or pain on the scalp
 – Follicular pustules or scaling suggesting inflammation

• Atypical Presentation of Common Alopecias
 – Unusual pattern or location of hair loss that doesn’t fit androgenetic (pattern) alopecia or alopecia areata
 – Rapid progression despite standard treatments

• Lack of Response to Treatment
 – No improvement after 3–6 months of appropriate therapy for presumed alopecia areata or androgenetic alopecia
 – Worsening signs despite anti-inflammatory or immunosuppressive medications

• Concern for Less Common Disorders
 – Fungal infections not confirmed by microscopy or culture
 – Cutaneous lupus erythematosus or lichen planopilaris suspected clinically
 – Rare genetic or metabolic hair diseases

---

Timing Is Important

A well-timed biopsy increases diagnostic yield:

• Active Disease Phase: Ideally within 4–6 weeks of lesion onset or when hair shedding is most active
• Untreated or Minimally Treated Area: Avoid areas heavily treated with topical or injected steroids to prevent masking histologic features
• Edge of Lesion: For scarring alopecia, sample the border where old and new hair loss meet to capture both diseased and normal follicles

---

How Is the Procedure Performed?

1. Local Anesthesia
   • Numbing the skin with lidocaine or similar agent
2. Punch Biopsy
   • Two 4 mm punches—one for vertical sections, one for transverse sections—give the pathologist a full picture of follicle structure and inflammation
3. Specimen Handling
   • Immediate placement in proper fixative (e.g., formalin for vertical, special medium for transverse)
4. Closure
   • Simple stitch or adhesive strip; small scar (usually <5 mm) remains

Most patients tolerate the procedure well. Total time is 15–20 minutes, and discomfort is minor, similar to a vaccine shot.

---

What Can a Biopsy Show?

• Non-Scarring Alopecia
  • Increased resting (telogen) hair follicles in telogen effluvium
  • Peribulbar lymphocytes (“swarm of bees”) in alopecia areata
• Scarring Alopecia
  • Destruction of follicular structures replaced by fibrosis
  • Specific inflammatory infiltrates in lichen planopilaris, frontal fibrosing alopecia or discoid lupus
• Infectious Causes
  • Fungal elements in tinea capitis or bacterial colonies

Accurate diagnosis steers therapy: anti-fungals for infections, immunomodulators for autoimmune forms, or anti-androgens for pattern hair loss.

---

Benefits vs. Risks

Benefits

• Definitive diagnosis when noninvasive tests fall short
• Prevents unnecessary prolonged treatments
• Tailors therapy to the exact disease process

Risks

• Mild pain or tingling at the site
• Small scar (often hidden by surrounding hair)
• Rare wound infection or bleeding

Overall, complications are uncommon, and healing typically takes 7–10 days.

---

Alternatives and Complementary Tests

Before jumping to a biopsy, your doctor may suggest:

• Dermoscopy/Trichoscopy: High-magnification scalp exam to look for miniaturized hairs, black dots or yellow dots
• Blood Tests: Thyroid panel, iron studies, ANA, ferritin, vitamin D
• Hair Pull or Pluck Test: Assesses shedding patterns
• Fungal Culture: If tinea capitis is suspected

If these remain inconclusive or if scarring is suspected, a biopsy becomes the next best step.

---

Special Note on Alopecia Areata

Alopecia areata often presents as smooth, round patches of hair loss. If you think you might have it, consider a free, online “symptom check for Alopecia Areata” to learn more about your signs and whether to seek medical care.

---

After the Biopsy

• Keep the area clean and dry for 24–48 hours
• Remove stitches in 7–10 days (if used)
• Watch for redness, increasing pain or discharge—contact your doctor if these occur
• Expect a tiny, well-healed scar hidden by hair regrowth

---

When to Talk to Your Doctor

If you notice:

• Rapidly progressing hair loss
• Scalp pain, burning or intense itching
• Any signs of infection after the biopsy (fever, spreading redness)
• Other worrisome symptoms like weight loss, fatigue or new skin lesions

Always discuss any concerns or unusual findings with a qualified healthcare provider. A scalp biopsy is a safe, informative procedure that helps dermatologists and pathologists reach the right diagnosis—and get you on the best path to treatment. If you experience life-threatening or serious symptoms at any time, seek urgent medical attention.