Alopecia areata is one of the most common cause of non-scarring alopecia. The pathogenesis is still unclear, however, it is believed to be an autoimmune disease. This disease is not a life-threatening condition but it has a significant psychological impact to patient's quality of life.

Many triggers have been proposed such as viral infection, stress and neurologic factors. There are many studies show the correlation between disease activities and neurotransmitters level. Substance P and calcitonin gene-related peptide play major role in early stage of disease. These substances cause imbalance of CD4/CD8 lymphocyte in pathologic site and loss of immune privilege of hair follicles.

The conventional treatment of alopecia areata with intralesional corticosteroid injection might treat the end of pathogenesis process.

There is no therapeutic intervention for the origin of disease. Fortunately, botulinum toxin A could be a novel treatment of alopecia areata. The botulinum toxin A demonstrates inhibition release of substance P in many publications.

To sum up, the treatment of alopecia areata with intralesional corticosteroid injection still be a standard treatment, nevertheless, patients have to receive this treatment every month until regrowth of scalp hair. Corticosteroid injection have several side effects, for example, skin atrophy, pigmentary change and hypothalamic-pituitary-adrenal axis suppression. Moreover, injection pain is also affect to psychological aspect .

This study purpose is to evaluate the efficacy of botulinum toxin A for alopecia areata and reduce corticosteroid side effects, as well as, others opportunity cost. There is no prospective, randomized-controlled trial of comparison study between botulinum toxin A injection and corticosteroid injection for alopecia areata, therefore, investigators conduct this study for the greatest benefit to alopecia areata patients and for the future research in disease etiology.

Inclusion criteria

1. Patients must be above 18 years old
2. Newly diagnosed with multiple alopecia areata
3. Patient has lesions on the both side of the scalp.
4. Lesions's diameter varies between 2-6 cms

Exclusion criteria

1. Having active scalp inflammation
2. Allergic to botulinum toxin A or human albumin
3. Receiving any medication that interfere efficacy of botulinum toxin such as macrolides antimicrobial agents or neuromuscular medications
4. Diagnosed with neuromuscular diseases such as Myasthenia gravis
5. Pregnant, breast feeding, plan to pregnant patients

Inclusion criteria

• Patients must be above 18 years old
• Newly diagnosed with multiple alopecia areata
• Patient has lesions on the both side of the scalp.
• Lesions's diameter varies between 2-6 cms

Exclusion criteria

• Having active scalp inflammation
• Allergic to botulinum toxin A or human albumin
• Receiving any medication that interfere efficacy of botulinum toxin such as macrolides antimicrobial agents or neuromuscular medications
• Diagnosed with neuromuscular diseases such as Myasthenia gravis
• Pregnant, breast feeding, plan to pregnant patients