This study evaluates the clinical effect of foot injection of the bacteria protein Botulinum toxin A on plantar pain in patients with EBS (epidermolysis bullosa simplex) or PC (pachyonychia congenita).
Epidermolysis bullosa simplex (EBS) is the most common subtype of epidermolysis bullosa and mutations in keratin genes (KRT 5/14) are responsible for this condition. Painful blisters and keratoderma of the feet are common and the blisters in EBS typically get worse in the summer due to sweating and increased environmental heat. Since 2010, also the related condition pachyonychia congenita (PC) is included in the study. The primary objective of the study is to evaluate the clinical effect of Botulinum toxin A (Dysport®), injected in the foot, on plantar pain in patients with EBS or PC. Quality of life, pain in feet, effect duration, plantar sweating and safety of the treatment will also be studied.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
40
Single injection in patients´ soles with Btx A in one foot and sodium chloride in the other, with the possibility of a second injection after 12 weeks. The drug will be given in general anaesthesia after curettage of the focal hyperkeratoses. Only the areas with focal hyperkeratoses will be injected with 50 ul per injection.The active drug Btx A (Dysport®, solution for injection) has a concentration of 100 U/ml, and the maximum dose is 300 U per foot.
Placebo preparation without active compound, administered as the active drug.
Svettmottagningen, Sofiahemmet
Stockholm, Sweden
RECRUITINGDetermination of the difference between treated and untreated foot in change of pressure (measured by manometry) to reach unbearable pain, VAS=8, from baseline to 5 week after injection.
Time frame: 5 weeks
Quality of life using a questionnaire (DLQI)
Time frame: 12 or 17 weeks
Pain in feet using a questionnaire (VAS)
Time frame: 5, 12 (and 17) weeks
Effect duration measured with manometry (same as primary end-point but measured at week 12)
Time frame: 12 weeks
Safety by recording of reported adverse events (AE) by the patient at the clinic visits
Time frame: 5, 12 (and 17) weeks
Foot-sweating using iodine-starch imprints before and after injections
Time frame: 0 weeks
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