Introduction
Botulinum toxin has been used to treat plantar blistering and pain in 7 epidermolysis bullosa simplex patients, including one child, with excellent but transient success (Table I). Most of these patients were treated with abobotulinumtoxinA, including the indexed pediatric patient. We recently investigated the use of onabotulinumtoxinA to treat epidermolysis bullosa simplex (EBS) symptoms in a pediatric patient, making this successful treatment unusual. Dose equivalence ranging from 2:1 to 4:1 abobotulinumtoxinA to onabotulinumtoxinA, respectively, has been suggested for the treatment of glabellar wrinkles and axillary hyperhidrosis, but further evidence is needed to determine the appropriate dose for management of EBS symptoms in both pediatric and adult patients.3 Additionally, the relative importance of the toxin's role in hyperhidrosis reduction and on local neurotransmitter release in neuropathic pathways deserves exploration.
Table I.
Reported cases of EBS symptoms treated with botulinum toxin
| Study | Age, y | Location | Dosing regimen∗ | Time to effect | Total treatments | Duration of effect | Course |
|---|---|---|---|---|---|---|---|
| Abitbol and Zhou1 | 43 | Right foot | Botox (100 U to 1 foot) | 2 wk | 1 | Unknown | Reduction in blistering and surface area involvement |
| Swartling et al2 | 7 | Feet | Dysport (170-250 U) | Unknown | 3 | 4 mo | Improvement in callosities/pedal pain; blister formation unchanged |
| Swartling et al2 | 46 | One foot | Dysport (300 U) | Unknown | 1 | 3 mo | Improvement in callosities/pedal pain/blister formation |
| Swartling et al2 | 30 | One foot | Dysport (300 U) | Unknown | 1 | — | No response to treatment |
| Swartling et al2 | 46 | Feet | Dysport (576-600 U) | Unknown | 3 | 3 mo | Callosities/blister formation/pedal pain much improved |
| Swartling et al2 | 33 | One foot | Dypsort (315 U) | Unknown | 1 | 3 mo | Callosities/blister formation improved; pedal pain not improved |
| Swartling et al2 | 24 | Feet | Dysport (580-700 U) | Unknown | 4 | 3.5 mo | Blister formation/pedal pain improved; callosities not improved |
| Current study | 6 | Feet | Botulinum toxin (50 U; 100 U total) | 2 wk | 2 | 3 mo | Significant improvement with fewer, smaller blisters/decreased pedal pain and odor |
Botox is manufactured by Allergan, Parsippany, NJ. Dysport is manufactured by Galderma, Fort Worth, TX.
Case report
A 6-year-old African-American boy with a history of EBS presented with painful blisters on the plantar aspect of both feet. The hyperhidrosis was fairly well controlled during the winter months with glycopyrrolate, 1 mg daily. However, he noted continued exacerbations of plantar blistering, hyperhidrosis, tenderness, and malodor with warmer temperatures. Given the recalcitrance to other interventions and after informed consent, the patient was administered 50 U of onabotulinumtoxinA in 4 mL preserved normal saline under general anesthesia in the operating room in January 2013. Injections were intradermal and placed 1.5 to 2 cm apart, 1 U per site on the weight-bearing areas of the plantar surface: sole, ball, and heel of each foot, excluding the arch. A second onabotulinumtoxinA treatment of 100 U, 2 U per site, was given 4 months after the first administration. The patient tolerated both procedures well without complication He experienced decreased pain, bullae, malodor, and less hyperhidrosis, first noted approximately 2 weeks after each treatment. The patient continued to have baseline pain along the plantar surface of his feet, especially with increased physical activity. However, overall pain was decreased, which was attributed to fewer and smaller bullae. The patient's symptoms were noted to recur approximately 3 months after each onabotulinumtoxinA injection. He received 2 further treatments using the same dosing regimen and denied any additional side effects. Of note, he is able to stay involved with sports activities, including football, in the summer and fall because of his improvement.
Discussion
EBS results from mutations in either KRT5 or KRT14, encoding partner keratins 5 or 14. The resultant increase in keratinocyte fragility leads to bullae, compensatory hyperkeratosis, plantar pain, and a decreased quality of life.4 Treatment is supportive and consists primarily of wound care, avoidance of mechanical stress, and minimizing excessive skin warmth and sweating, which are both recognized triggers.1, 5, 6
Footnotes
Funding sources: None.
Conflicts of interest: None declared.
References
- 1.Abitbol R., Zhou L. Treatment of epidermolysis bullosa simplex, weber cockayne type, with botulinum type A. Arch Dermatol. 2009;145:13–15. doi: 10.1001/archdermatol.2008.546. [DOI] [PubMed] [Google Scholar]
- 2.Swartling C., Karlqvist M., Hymnelius K., Weiss J., Vahlquist A. Botulinum toxin in the treatment of sweat-worsened foot problems in patients with epidermolysis bullosa simplex and pachyonychia congenita. Br J Dermatol. 2010;163:1072–1076. doi: 10.1111/j.1365-2133.2010.09927.x. [DOI] [PubMed] [Google Scholar]
- 3.Karsai S., Raulin C. Botox and Dysport: is there a dose conversion ratio in dermatologyand aesthetic medicine. J Am Acad Dermatol. 2010;62:346–347. doi: 10.1016/j.jaad.2008.12.028. [DOI] [PubMed] [Google Scholar]
- 4.Horn H., Tidman M. Quality of life in epidermolysis bullosa. Clin Exp Dermatol. 2002;27:707–710. doi: 10.1046/j.1365-2230.2002.01121.x. [DOI] [PubMed] [Google Scholar]
- 5.Sprecher E. Epidermolysis bullosa simplex. Dermatol Clin. 2010;28:23–32. doi: 10.1016/j.det.2009.10.003. [DOI] [PubMed] [Google Scholar]
- 6.Pai S., Marinkovich M. Epidermolysis bullosa: new and emerging trends. Amer J Clin Dermatol. 2002;3:371–380. doi: 10.2165/00128071-200203060-00001. [DOI] [PubMed] [Google Scholar]