Relapsing-remitting severe generalized muscular weakness after botulinum toxin treatment for hyperhidrosis

Safety of available and emerging drug therapies for hyperhidrosis

INTRODUCTION

Hyperhidrosis affects 4.8% of the U.S. population and has been underestimated by physicians for long time despite considerable interference with quality of life. Many patients suffer from primary (idiopathic) hyperhidrosis which results from over-activity of sympathetic nerves and is restricted to specific body areas, mostly the axillae, palms, soles, or head. Secondary hyperhidrosis is caused by an underlying disease or the intake of medications and often involves large parts of the body. Numerous effective therapies with topical or systemic drugs and surgical options are available. Areas covered: Efficacy and safety data on aluminum salts, anticholinergic drugs for topical or systemic application, and on intradermal botulinum toxin injections used to treat hyperhidrosis are critically evaluated, including data from clinical trials with focus on possible side effects and long-term complications in dispute. Expert opinion: Hyperhidrosis often responds well to available therapies. Depending on the type of hyperhidrosis treatment should be topical/local or systemic. Most of the side effects are mild, transient and easily manageable. In case of systemic treatment with anticholinergics low dosing and up-titration of medication is necessary to avoid severe adverse effects. Concerns about the promotion of breast cancer and Alzheimer disease by topical aluminum salts are unsolved.

Proximal muscular atrophy and weakness: An unusual adverse effect of deferasirox iron chelation therapy

Deferasirox is a standard treatment for chronic transfusional iron overload. Adverse effects of deferasirox have been reported in large prospective studies. We report two cases of monozygotic twins manifesting with proximal muscular atrophy and weakness under deferasirox. Discontinuation of deferasirox resulted in symptom improvement and ultimately in complete remission five months after successful haematopoietic stem cell transplantation. Broad diagnostic work-up could not bring evidence of another aetiology of muscular weakness. Iron overload or beta thalassemia itself as a cause is considered unlikely in our patients because the chronological coincidence of muscular symptoms was contra-directional to serum ferritin levels and significant clinical improvement was observed promptly after cessation of deferasirox even before transplantation. These observations suggest that the development of muscular weakness in patients on deferasirox should be recognised as a possible adverse effect of the drug.