DISCUSSION
skin disorder, muscle paralysis, chronic recurrent inflammatory skin disease, paralysis, scaly, seborrhea
SKIN DISORDER, DISEASE, PATHOPHYSIOLOGY, SEBORRHOEIC DERMATITIS, SEBORRHEIC DERMATITIS, DISEASES, SEBORRHEA
A common skin disorder, seborrheic dermatitis is a chronic recurrent inflammatory skin disease clinically manifested by scaly and erythematous patches with indistinct borders.The pathophysiology proposed for the occurrence of seborrheic dermatitis states that a non‐immunological stimulation of the production of unsaturated fatty acid deposits on the skin surface is the cause of this disease.Most previous studies have evaluated the effect of botulinum toxin, emphasizing the reduction of sebum production by the sebaceous glands after the action of botulinum toxin. In addition, its role in reducing the symptoms of seborrheic dermatitis has been demonstrated by the intradermal injection of this substance.On the other hand, in a 2013 study by Amy E Rose et al., with the aim of investigating the effect of intradermal botulinum toxin injection on the improvement of oily skin, 25 patients who were injected with botulinum toxin in the forehead area were studied. As a result of this study, it was found that intradermal injection of botulinum toxin in the forehead area was associated with a significant decrease in sebum production and 91% patient satisfaction.Also, in a study conducted in 2018 by Maria Shirshakova and colleagues on 12 patients with an average age of 35 years, with the aim of investigating the effect of using botulinum toxin type A for treatment of facial seborrhea, it was shown a positive and statistically significant relationship between the injection of this toxin and improvement of skin seborrhea.Previous researches have investigated the mechanism of action of this toxin; In a study conducted by Kyoung Rho‐Nark et al. in 2021 with the aim of investigating the effect of botulinum neurotoxin type A on the treatment of seborrhea of face, it was concluded that this toxin can stimulate the transmission of cholinergic messages in the autonomic nervous system and affect sebaceous glands reduce the production of sebum and thus be used in the treatment of diseases caused by excessive activity of sebaceous glands.In the results of the present study, while evaluating the information related to 20 patients referred to the skin clinic with an average age of 40.05 (±11.56) years who underwent botulinum toxin injection to remove facial wrinkles and were simultaneously suffering from to seborrheic dermatitis on the scalp or face, despite the reduction of the average scores in all the examined criteria of seborrheic dermatitis symptoms in the examination 1 month after botulinum toxin injection, no significant effect of using this toxin on the improvement of patients' symptoms was seen (While in the study of Amy E Rose et al. in 2013, the first follow‐up session of patients was done one week after Botox injection and was associated with a 75% reduction in sebum productionAnother influential factor is the injection technique and toxin access to the sebaceous glands; in this way, the shallowness of the injection depth may cause its ineffectiveness, and its deepness can lead to paralysis of the deep skeletal muscles.It's worth noting that in Sapra et al.’s 2017 study, which compared the efficacy of intradermal and intramuscular botulinum toxin A injections for treating skin aging symptoms in ten women aged 35 to 65 years, no significant reduction in skin sebum secretion was observed.Based on this, it is possible to imagine a dual role for botulinum toxin in its effect on seborrheic dermatitis. The hypothesis that can be proposed is that intradermal injection of botulinum toxin, with the previously mentioned mechanisms, reduces the incidence and improves seborrhoeic dermatitis lesions. On the other hand, intramuscular injection of botulinum toxin causes muscle paralysis and delays the complete discharge of sebum, leading to the aggravation of seborrheic dermatitis symptoms. In our study and Sapra's study,