Botulinum toxins has been approved by the FDA to treat chronic migraine. Botox had been shown to inhibiting the release of inflammatory mediators and peripheral neurotransmitters from sensory nerve to treat neuropathic pain. In the clinical practice, botox indeed effect in scar pain. However, investigators need well controlled study to prove this finding and assess the improvement of scar appearance.

After surgery or trauma, scar tissues would form during the healing process. However, hypertrophic scars and keloids might happen to some patients, both of which are often pruritic and erythematous. Besides, the markedly elevated tumor-like appearance usually brings much concern to patients. Moreover, significant pain or discomfort could happen to keloids. Various treatment strategies were mentioned but without a solid solution to all of the scars. Investigators hope to evaluate the differences of scar volume, appearance and symptoms (itching and pain) in participants receiving simultaneous intralesional injection of Botulinum toxin type A and/or steroids. Besides, side effects would also be recorded. Investigators hope to establish a more effective intralesional injection therapy for participatns suffering from hypertrophic scars and keloids.

Inclusion Criteria:

1. Patients have visible hypertrophic scars or keloids over three months after trauma or surgery.
2. Patients have symptoms of pain, itching or erythema.

Exclusion Criteria:

1. Patients had either Botulinum toxin type A or Triamcinolone intralesional before in the same scar
2. The scar size is larger than 10 cm2
3. Immunocompromised status
4. Systemic infection status
5. Allergic to Botulinum toxin type A or steroids