15 March 2005

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2386 East Heritage Way, Suite B, Salt Lake City, Utah 84109 USA Phone +1-877-628-7300 • Email—[email protected] www.pachyonychia.org BJD THERAPEUTICS British Journal of Botulinum toxin in the treatment of sweat-worsened problems in patients with epidermolysis bullosa simplex and pachyonychia congenita C. Swartling,* M. Karlqvist,* K. Hymnelius,* J. Weis§ and A. Vahlquist* Departments of *Dermatology and §Radiology, and Centre for Research and Development, County Council of Ga¨vleborg, Uppsala University, University Hospital, SE-751 85 Uppsala, Sweden Sophiahemmet AB, Hidrosis Clinic, Box 5605, SE-114 86 Stockholm, Sweden

Summary

Correspondence Background Painful foot blistering is a common problem in patients with epider- Carl Swartling. molysis bullosa simplex (EBS) and pachyonychia congenita (PC). Hyperhidrosis, E-mail: [email protected] a condition which can be effectively blocked by plantar injections of botulinum toxin (Btx), often exacerbates the blistering. Accepted for publication 22 June 2010 Objectives A retrospective evaluation of the effects of Btx injections in 14 patients with EBS and PC with foot and painful callosities. Key words Methods After informed consent, patients with EBS (n = 6) and PC (n = 8), aged blisters, botulinum toxin, callus, epidermolytic 7–66 years, who had received Btx therapy at our centre since 2003, were disorders, hyperhidrosis, mutation included. The treatment consisted of multiple plantar injections of Btx A or Btx B Conflicts of interest after prior regional or general anaesthesia. Patients were interviewed about the None declared. treatment effect and were asked to score the improvement from 0 to 5, where 5 is ‘excellent’. One patient with PC with painful callosities was studied by DOI 10.1111/j.1365-2133.2010.09927.x magnetic resonance (MR) spectroscopic microimaging before and after Btx injec- tions to disclose any underlying blisters. Results In total, 76 treatments were evaluated (one to 19 sessions per patient). Thirteen patients (93%) reported reduced plantar blistering and pain; the improvement score was ‡ 4 in four of six patients with EBS and six of eight patients with PC. The mean effect duration was 3 months. No adverse events, apart from mild anticholinergic side-effects in two patients, were noted. MR spectroscopic microimaging showed disappearance of intraepidermal blistering after Btx therapy. Conclusions Plantar injection of Btx is an efficient, long-lasting and safe treatment of painful blistering and callosities in EBS and PC that can be given repeatedly without loss of efficacy.

Epidermolysis bullosa simplex (EBS) and pachyonychia con- [Dowling–Meara (DM); 1 : 200 000] with blistering all over genita (PC) belong to a group of congenital keratinopathies the body.4 PC (OMIM 167200 ⁄167210) has a prevalence of characterized by stress-induced epidermolysis and hyperkerato- about 1 : 100 000. It starts with thickening of the nails and is sis due to cytoskeletal fragility and clumping of intermediate later followed by foot blisters and painful callosities. Two filaments (IFs). There is no curative treatment for keratino- forms of PC exist: type 1 with mucosal involvement, and type pathies, but siRNA therapy has shown promising results in 2 with steatocystoma multiplex.5 PC.1 In patients with both EBS and PC, foot blisters and callosi- EBS and PC are caused by dominant negative keratin muta- ties deteriorate in a hot and humid environment, especially tions affecting the heterodimerization of IFs expressed in the when plantar hyperhidrosis is prominent. Alas, topical anti- basal and spinous layers of and encoded by sweating agents, such as glutaric aldehyde and aluminium KRT5 ⁄KRT14 and KRT6 ⁄KRT16 ⁄17, respectively.2,3 EBS (OMIM chloride, are insufficient to reduce the foot problems.6 How- 131800 ⁄131760) exists in two forms: the localized subtype ever, intracutaneous injection of botulinum toxin (Btx) is a previously called Weber–Cockayne; prevalence 1:25 000) with more efficacious treatment of focal hyperhidrosis.7,8 Btx inhib- predominantly foot blisters, and the generalized subtype its eccrine sweat glands by blocking the acetylcholine

2010 The Authors 1072 BJD 2010 British Association of Dermatologists 2010 163, pp1072–1076 Botulinum toxin for EBS and PC, C. Swartling et al. 1073 pathway. The anaerobic bacterium Clostridium botulinum produces PC were included in a previous report of the short-term different types of Btx named A to G. Type A and type B are effects of Btx therapy.11 commercially available. Btx A and Btx B differ in pharmaco- dynamics, covering proteins and additives in the vials. Differ- Anaesthesia ent Btx A preparations are not exchangable regarding the potency of 1 U.9,10 Foot analgesia was accomplished either by bilateral intrave- Several years ago, we began treating a few patients with PC nous regional anaesthesia (IVRA)13 with a low tourniquet and ) by plantar injections of Btx and noticed a spectacular reduc- 25 mL prilocaine (5 mg mL 1) given intravenously to each tion in pain from walking.11 We also reported preliminary foot (n = 39 sessions), or by general anaesthesia (n =37 good results in two patients with EBS with pedal blisters,11 sessions). The selection of method was dependent on the which was recently confirmed by others.12 We have now trea- patient’s age and attitudes to anaesthesia (see Table 1). ted a total of 14 patients with EBS and PC, and wish to report in a retrospective study our experience with Btx therapy for Botulinum toxin injections this indication. After reducing the callosities by curettage, all patients received plantar injections with Btx A (Dysport; Ipsen, Patients and methods ) Slough, U.K.) 100 U mL 1. The individual doses are shown in Table 1. Due to treatment resistance, three patients were Patients later switched to Btx B (Neurobloc; Eisai, Stockholm, Swe- ) Six patients with EBS of localized type or DM (age den) 250 U mL 1. Our initial strategy was to distribute Btx 7–46 years) and eight patients with PC of type 1 or 2 (age evenly on the sole, injecting it intradermally every 15 mm 26–66 years) were included in the study after informed in a checked pattern. This regimen was later modified so that consent (Table 1). The patients were referred from all parts only weight-bearing areas of the feet were treated, distri- of Sweden and were followed for a maximum of 6 years. A buting the same total dose especially below blisters and diagnosis of EBS or PC was established using clinical criteria, callosities. inheritance pattern, and ⁄or KRT mutation analysis (kindly Similar procedures have been repeatedly approved by the performed by Dr Paul Bowden, Cardiff, U.K., and Dr Marie local ethical committee in Uppsala for other studies of Btx Virtanen, in Uppsala). All patients had a history of sweat- therapy performed over the years.13 All treatments were worsened blisters or painful hyperkeratoses that negatively performed at the Department of Neurology, Uppsala Univer- affected their activities of daily life. Three of the patients with sity Hospital.

Table 1 Patient characteristics, global outcome and details of the therapy with botulinum toxin (Btx)

Global Preferred Age Clinical Affected No. of Dose (U) of Btx A improvement Effect duration type of Patient (years) ⁄sex subtype Inheritance gene treatments or Btx B (score)a (months) anaesthesia EBS 1b 7 ⁄F Loc. AD NA 3 A: 170–250 5 4 General EBS 2b 46 ⁄M Loc. AD NA 1 A: 300 (one foot) 4 3 IVRA EBS 3 24 ⁄F Loc. AD NA 4 A: 580–700 5 3Æ5 IVRA EBS 4 46 ⁄F DM AD K5 3 A: 576–600 5 3 IVRA EBS 5 30 ⁄M Loc. AD K5 1 A: 300 (one foot) 0 0 IVRA EBS 6 33 ⁄M DM AD K5 1 A: 315 (one foot) 3 3 IVRA PC 1 32 ⁄F PC-2 AD NA 2 A: 600 4 2 General PC 2b 36 ⁄F PC-2 AD NA 6 A: 600–700 4 3 IVRA PC 3b 66 ⁄M PC-2 AD NA 1 A: 600 3 3 IVRA PC 4c 26 ⁄M PC-1 Spor. – 19 A: 480–700; B: 2500 4 3 General PC 5d 37 ⁄F PC-1 AD K6a 16 A: 466–600; B: 2500 4 2Æ5 General PC 6d 44 ⁄F PC-1 AD K6a 16 A: 500–600; B: 2500 4 2Æ5 IVRA PC 7 42 ⁄F PC-2 AD NA 1 A: 200 (one foot) 4 12 IVRA PC 8b 33 ⁄F PC-2 AD NA 2 A: 670–700 3 4 IVRA

A, Btx A (Dysport); AD, autosomal dominant; B, Btx B (Neurobloc); DM, Dowling–Meara subtype; EBS, epidermolysis bullosa simplex; IVRA, intravenous regional anaesthesia; K5, keratin 5; K6a, keratin 6a; Loc., localized subtype (previously called Weber–Cockayne); NA, not analysed; PC, pachyonychia congenita; PC-1, PC type 1; PC-2, PC type 2; Spor., sporadic, no family history. aScore 0–5 where 0 = no effect and 5 = excellent. bFather and daughter(s). cAlso included in a previous report of the short-term effects of Btx therapy,11 negative mutation screening of K6a, K16 and K17 by Dr Paul Bowden (personal communication). dSisters, also included in the short-term follow up,11 and in a paper discussing the genetic basis of PC.3

2010 The Authors BJD 2010 British Association of Dermatologists 2010 163, pp1072–1076 1074 Botulinum toxin for EBS and PC, C. Swartling et al.

Table 2 Treatment outcome: detailed results of a telephone interview. Evaluation procedure Individual improvement scores (0–3)ª after botulinum toxin treatment A retrospective evaluation of the details and outcome of each based on the patients’ responses to three questions treatment session was accomplished by searching the patient’s file and by a structured telephone interview in which one of Change in Change in Change in Sum of b the authors (C.S.) asked the patients about their opinion of Patient callosities? blistering? pedal pain? scores the global improvement of foot symptoms (score 0–5 where EBS 1 2 0 3 5 0 = no effect and 5 = excellent) and the improvement of EBS 2 3 1 3 7 EBS 3 0 2 2 4 callosities, blisters and pain, using a score range from 0, ‘no EBS 4 1 3 3 7 improvement’ to 3, ‘very much better’ for each symptom. EBS 5 0 0 0 0 Patients were also questioned about the effect duration, EBS 6 1 3 0 4 side-effects, and whether or not they would recommend the PC 1 0 2 2 4 therapy to others with the same disease. PC 2 3 3 2 8 In one case (PC 8), a painful callus was also investigated by PC 3 1 0 1 2 magnetic resonance (MR) spectroscopic microimaging before PC 4 3 3 3 9 PC 5 2 3 2 7 and after Btx therapy with the intention of demonstrating a PC 6 1 0 3 4 reduction of blistering and maceration below a hyperkeratotic PC 7 1 No blisters 2 3 skin surface. This type of MR microimaging is a relatively new PC 8 3 2 2 7 technique to visualize skin morphology at a high resolution without chemical shift artifacts.14–16 In a parallel experiment, EBS, epidermolysis bullosa simplex; PC, pachyonychia congenita. three weight-bearing areas (, forefoot and big toe) were ª0, no effect; 1, a little better; 2, much better; 3, very much better. b0–2 ⁄3, treatment failure; 4–5, moderate improvement; investigated by manometry before and after therapy in order (6–)7–8, good improvement; 9, excellent effect. to assess the maximal tolerable pressure (in Newton, N) before the patient complained of maximum pain. The pain was recorded on a visual analogue scale, where a value of 10 is the maximum score. patients’ weighting of different symptoms. For example, a few patients experienced a marked improvement of pain but only Results little reduction in blistering, whereas others showed a similar improvement of all three symptoms (see Table 2). The sum of scores was highest (8 or 9) in two patients with PC who had Patient characteristics and overall results of therapy been treated many times, but ‘good improvement’ (score 7) The patients (five males and nine females) were mostly was also noted in two patients with EBS treated only a few middle-aged, but one child with EBS was also included after times. the parents’ informed consent (Table 1). The number of treat- Table 1 shows that the effect duration of Btx therapy ranged ment sessions per patient ranged from one to 19. Our longest from 2 to 12 months, with a mean value of 3 months for experience is with three patients with PC who have been both groups of patients. The very long effect duration in successfully treated 16–19 times over a period of 5–6 years. patient PC 7 is clearly exceptional and was for unknown However, the majority of patients had received three or fewer reasons observed only once. treatments over the last 3 years. Although most of the responders at the first session Judged from the results of the telephone interview, the glo- remained responsive to Btx A during repeated sessions, three bal improvement score was highest (5) in three patients with of the patients with PC were later successfully switched to Btx EBS who had received three or four repeated treatments of B because of insufficient treatment effects. Only in one case both feet, whereas five of the patients with PC scored 4 (‘very (PC 5) was the treatment resistance to Btx A suspected to be good’) after having received many more bilateral treatments. due to immunization against the toxin, with no obvious The remaining responders (n = 5) either scored 3 (‘good’) cross-reaction against Btx B. The dose per session ranged from ) or, when only one foot was treated, 3 or 4 (‘good’ or ‘very 170 to 700 U for Btx A (Dysport) (10 U kg 1 was used good’). One patient (EBS 5) was a nonresponder after the first for the child), but the dose was fixed to 2500 U for Btx B treatment session and did not want to try Btx therapy again. (Neurobloc). The mean improvement score was 3Æ8 for both diagnosis The preferred method of anaesthesia was IVRA in 10 groups. patients and general anaesthesia in four patients (see Table 1). Table 2 shows in more detail the individual improvement IVRA has the advantage of allowing patients to return to work scores of callosities, blistering and pain from walking. The soon after treatment. General anaesthesia was used in the child sum of these scores should ideally correlate with the individ- with EBS and in three patients with PC where IVRA either did ual global improvement score (see Table 1). The minor not produce sufficient analgesia or the patients complained of discrepancies observed between the two ranking systems can pain or discomfort from the tourniquet cuff during the IVRA easily be explained by interindividual variations in the procedure.

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The whole procedure was generally well tolerated and only Interestingly, two patients with insufficient effects from Btx mild and transient Btx-related side-effects were noted in three A benefited from switching to Btx B despite no evidence of an female patients: dysphagia in one case, and dry mouth, immunization against Btx A. Although both toxins inhibit the accommodation problems and urinary stress incontinence in release of acetylcholine from peripheral cholinergic nerve end- two cases. ings,17 they have slightly different mechanisms of action. The All responders (13 of 14 patients) said that they would rec- light chain of the toxin is internalized and proceeds to splice ommend Btx therapy to other patients with similar foot prob- different intracellular proteins among the so-called SNARE lems. complex [i.e. syntoxin, synaptosomal-associated protein 25 (SNAP-25) and vesicle-associated membrane protein (VAMP)].18 Btx A splices SNAP-25 and Btx B splices VAMP, Magnetic resonance spectroscopic microimaging and thus differently inhibiting the docking of the acetylcholine manometry before and after botulinum toxin injection vesicle to the cell membrane, leading to a chemical denerva- To obtain a better understanding of the mechanism of action tion of the neurone. The time elapsed before reinnervation of by which Btx ameliorates painful callosities in PC, one of the the sweat glands by sprouting has become complete decides patients (PC 8) underwent MR microimaging of a tender cal- the duration of treatment effect.19 This, in turn, is possibly lus without macroscopic evidence of before treatment related to inter- and intraindividual variations in the intrinsic (Fig. 1a). Interestingly, the MR picture revealed an intra- levels and function of SNAP-25 and VAMP, which may help epidermal blister (Fig. 1b), which was absent 1 month after to explain individual differences in patient response. treatment (Fig. 1c), when both pain and had Axillary and palmar hyperhidrosis can be effectively elimi- improved. Manometry performed on three weight-bearing nated for a long period (median effect 9–10 months) using areas of both feet showed that the treated side tolerated intracutaneous injections of Btx.7 The effect of Btx in plantar approximately 80% more pressure than the untreated foot hyperhidrosis is unfortunately not well studied. The rationale (mean: 39 vs. 22 N). for using Btx in keratinopathies is to inhibit a sweat-induced maceration of the fragile epidermis, thus reducing plantar blis- Discussion tering and pain. However, also patients with PC with no overt hyperhidrosis or clearly visible blisters reported relief of The most striking finding of this retrospective study is the tenderness of calluses within a few days after treatment. One long-standing reduction in painful blisters and calluses after possible explanation is that calluses are painful because of a Btx injections in both groups of patients. Of 14 patients trea- concealed epidermal maceration elicited by normal amounts of ted with Btx over a period of 6 years, all but one (EBS 5) con- sweat. Indeed, MR spectroscopic microimages of a tender PC sidered the treatment effective and wished to recommend it to callus showed an intraepidermal separation containing opaque others. The reason for the treatment failure in EBS 5 is uncer- material with features of macerated proteins in a blister. The tain; he received Btx A injections on the right foot only once blister disappeared after Btx therapy and the pain reduction and did not want to repeat the whole procedure. Maybe the was sufficient to permit the patient to start walking more freely toxin was unintentionally deposited too superficially in this and to use intensive pedicure to reduce the callous mass. case, and did not reach the underlying sweat glands. The Although reduced blistering per se is the most plausible injection technique is quite demanding and the nurses who explanation for pain relief by Btx therapy of pedal problems administer the toxin at our centre have since been instructed in EBS and PC, we also noticed that the reduction in tender- to make the injections deeper into the involved skin, especially ness often preceded the general improvement of the symp- below blisters and callosities. toms. This implies a more direct effect of Btx on sensory

(a) (b) (c)

Fig 1. Visualization of the treatment effects of botulinum toxin (Btx) in patient PC 8 using magnetic resonance (MR) spectroscopic microimaging. (a) Clinical appearance of a painful blister on the right foot (encircled) which was investigated by MR before (b) and 1 month after (c) local injections of Btx which produced healing of the blister and sustained pain relief. The MR pictures show an intraepidermal blister in (b), whereas in (c) the epidermis is intact. Resolution in plane was 0Æ1 · 0Æ1 mm, slice thickness 0Æ5 mm. Images were corrected for chemical shift artifacts. The most intense areas depict water content in epidermis and in blood vessels as well as fat in hypodermis.

2010 The Authors BJD 2010 British Association of Dermatologists 2010 163, pp1072–1076 1076 Botulinum toxin for EBS and PC, C. Swartling et al. nerves. Btx affects nociceptive C-fibres in the skin via inhibi- 2 Fuchs E, Coulombe P, Cheng J et al. Genetic bases of epidermolysis tion of neuropeptide release from sensory nerve axons.20 bullosa simplex and epidermolytic hyperkeratosis. J Invest Dermatol Interestingly, Btx also inhibits the vasodilation (flare) induced 1994; 103:S25–30. 3 Smith FJ, Liao H, Cassidy AJ et al. The genetic basis of pachyony- by silent nociceptors which initiate neurogenic inflamma- 21,22 chia congenita. J Investig Dermatol Symp Proc 2005; 10:21–30. tion. Perhaps a combination of all these mechanisms 4 Fine JD, Eady RA, Bauer EA et al. The classification of inherited explains the impressive effect of Btx on pedal tenderness in epidermolysis bullosa (EB): report of the Third International EBS and PC. Consensus Meeting on Diagnosis and Classification of EB. J Am Acad In conclusion, our study of a cohort of patients with geno- Dermatol 2008; 58:931–50. dermatoses treated over a period of 6 years with repeated Btx 5 Munro CS. Pachyonychia congenita: mutations and clinical presen- injections of the soles shows very encouraging results and only tations. Br J Dermatol 2001; 144:929–30. 6 Langan SM, Williams HC. A systematic review of randomized con- few and mild complications. This suggests that Btx treatment trolled trials of treatments for inherited forms of epidermolysis should be tested on a larger group of patients with EBS and PC bullosa. Clin Exp Dermatol 2009; 34:20–5. in a randomized, placebo-controlled trial where the major end- 7 Naver H, Swartling C, Aquilonius SM. Palmar and axillary hyperhi- point is the evaluation of plantar pain before and after Btx drosis treated with botulinum toxin: one-year clinical follow-up. treatment. Such a study should also examine the effects of Btx Eur J Neurol 2000; 7:55–62. treatment on the quality of life of patients with painful pedal 8 Hornberger J, Grimes K, Naumann M et al. Recognition, diagnosis, problems. We recommend that the procedure be performed and treatment of primary focal hyperhidrosis. J Am Acad Dermatol 2004; 51:274–86. only in facilities with experience in this treatment protocol. 9 Rystedt A, Swartling C, Farnstrand C et al. Equipotent concentra- tions of Botox and Dysport in the treatment of palmar hyperhidro- What’s already known about this topic? sis. Acta Derm Venereol (Stockh) 2008; 88:458–61. 10 Rystedt A, Swartling C, Naver H. Anhidrotic effect of intradermal • Painful foot blistering and callosities are common foot injections of botulinum toxin: a comparison of different products problems in patients with epidermolysis bullosa simplex and concentrations. Acta Derm Venereol (Stockh) 2008; 88:229–33. (EBS) and pachyonychia congenita (PC). 11 Swartling C, Vahlquist A. Treatment of pachyonychia congenita • There is so far no curative treatment and also a lack of with plantar injections of botulinum toxin. Br J Dermatol 2006; 154:763–5. effective symptomatic local treatment options for these 12 Abitbol RJ, Zhou LH. Treatment of epidermolysis bullosa simplex, keratinopathies. Weber–Cockayne type, with botulinum toxin type A. Arch Dermatol • The blisters in EBS and PC are often exacerbated by 2009; 145:13–15. hyperhidrosis, a condition that can be blocked by plan- 13 Bosdotter Enroth S, Rystedt A, Covaciu L et al. Bilateral forearm tar injections of botulinum toxin (Btx). intravenous regional anesthesia with prilocaine for botulinum toxin treatment of palmar hyperhidrosis. J Am Acad Dermatol 2010; 63:466–74. What does this study add? 14 Weis J, Astrom G, Vinnars B et al. Chemical-shift micro-imaging of subcutaneous lesions. MAGMA 2005; 18:59–62. • The results of our retrospective study in patients with 15 Weis J, Ericsson A, Astrom G et al. High-resolution spectroscopic EBS and PC indicate that local injection of Btx in plantar imaging of the . Magn Reson Imaging 2001; 19:275–8. 16 Weis J, Ericsson A, Hemmingsson A. Chemical shift artifact-free areas of painful blistering and callosities is an efficient, microscopy: spectroscopic microimaging of the human skin. Magn long-lasting and safe treatment option that can be given Reson Med 1999; 41:904–8. repeatedly without loss of efficacy. 17 Simpson LL. Molecular pharmacology of botulinum toxin and tetanus toxin. Annu Rev Pharmacol Toxicol 1986; 26:427–53. 18 Grumelli C, Verderio C, Pozzi D et al. Internalization and mecha- nism of action of clostridial toxins in neurons. Neurotoxicology 2005; Acknowledgments 26:761–7. 19 Swartling C, Naver H, Pihl-Lundin I et al. Sweat gland morphology We thank all patients for willingly taking part in this study and periglandular innervation in essential palmar hyperhidrosis and our dermatology colleagues for referring patients to us. before and after treatment with intradermal botulinum toxin. JAm Acad Dermatol 2004; 51:739–45. This study was supported by grants from the Welander-Finsen 20 Lucioni A, Bales GT, Lotan TL et al. Botulinum toxin type A inhibits foundation and the Uppsala University Hospital strategic funds sensory neuropeptide release in rat bladder models of acute injury (ALF). and chronic inflammation. BJU Int 2008; 101:366–70. 21 Kramer HH, Angerer C, Erbguth F et al. Botulinum toxin A reduces neurogenic flare but has almost no effect on pain and hyperalgesia References in human skin. J Neurol 2003; 250:188–93. 1 Smith FJ, Hickerson RP, Sayers JM et al. Development of therapeu- 22 Gazerani P, Pedersen NS, Staahl C et al. Subcutaneous botulinum tic siRNAs for pachyonychia congenita. J Invest Dermatol 2008; toxin type A reduces capsaicin-induced trigeminal pain and vaso- 128:50–8. motor reactions in human skin. Pain 2009; 141:60–9.

2010 The Authors BJD 2010 British Association of Dermatologists 2010 163, pp1072–1076