What medications can cause patchy hair loss?

Medications That Can Cause Patchy Hair Loss

Multiple medications can cause patchy hair loss, with the most common culprits being chemotherapy agents, mood stabilizers (particularly valproic acid and lithium), anticoagulants, antithyroid drugs, and certain antihypertensives. 1, 2

Types of Drug-Induced Hair Loss

Drug-induced hair loss typically manifests in two patterns:

1. Telogen Effluvium: Most common form where drugs push hair follicles prematurely into the resting phase

   • Usually diffuse thinning rather than patchy
   • Typically occurs 2-4 months after starting medication

2. Anagen Effluvium: More rapid and severe hair loss

   • Can appear patchy
   • Occurs within days to weeks of drug exposure
   • Most commonly associated with chemotherapy agents

Medications Associated with Patchy Hair Loss

Psychiatric Medications

• Lithium: Causes hair loss in 12-19% of long-term users 2
• Valproic acid/Divalproex: Precipitates alopecia in up to 12% of patients in a dose-dependent relationship; incidences up to 28% with high concentrations 2
• Carbamazepine: Associated with alopecia in up to 6% of users 2
• Antidepressants: Tricyclics, maprotiline, trazodone, and newer antidepressants can occasionally cause hair loss 2
• Antipsychotics: Haloperidol, olanzapine, and risperidone have been implicated in rare cases 2

Cardiovascular Medications

• Beta-blockers: Both systemic and topical forms can cause patchy hair loss 1
• Anticoagulants: All anticoagulant drugs can produce hair loss 1

Hormonal Medications

• Oral contraceptives: Can cause hair loss both while taking and after discontinuation 1
• Antithyroid drugs: All can produce hair loss 1

Other Medications

• Retinoids: Can cause patchy hair loss 1
• NSAIDs and salicylates: Rare but reported 1
• Miscellaneous: Cimetidine, amphetamines, bromocriptine, levodopa 1

Management of Drug-Induced Hair Loss

According to the British Association of Dermatologists' guidelines, management depends on the pattern and severity of hair loss:

• For patchy hair loss of limited extent: Intralesional corticosteroids may be effective 3
• For extensive patchy hair loss: Contact immunotherapy may be considered 3

Important Clinical Considerations

• Reversibility: Drug-induced hair loss is usually reversible upon discontinuation of the medication 1, 4
• Diagnosis: Confirming drug-induced alopecia is challenging and primarily relies on temporal association and improvement after drug cessation 1
• Patient Impact: Hair loss can significantly affect quality of life and may lead to poor medication compliance 2
• Confounding Factors: Before attributing hair loss to medication, exclude other triggers such as fever, severe illness, stress, and hormonal changes 5

Monitoring and Prevention

• Monitor patients on high-risk medications (lithium, valproic acid, anticoagulants)
• Consider dose reduction if possible when hair loss occurs 2
• Document baseline hair condition before starting high-risk medications
• Inform patients about the possibility of hair loss when prescribing these medications

Hair loss from medications represents an important side effect that can significantly impact quality of life and treatment adherence. Recognizing the medications most commonly associated with patchy hair loss can help clinicians make informed prescribing decisions and properly counsel patients about potential risks.