Endocrine Abstracts

Sweating in the absence of any physiological precipitant can be extremely distressing and unpleasant. Primary hyperhydrosis, usually affecting the palms of the hands, soles of the feet and the axillae, usually presents in teenage years and is managed by dermatologists. Secondary hyperhydrosis usually develops later in life, is more generalised and may be associated with flushing. The differential diagnosis is very long and includes systemic illness (such as lymphoma and chronic infections), neurological disorders (such as Parkinson’s syndrome and neuropathies), drugs (including SSRIs and tricyclic antidepressants) and withdrawal from certain drugs (including SSRIs). Endocrine disorders may also be associated with secondary hyperhydrosis and the typical list includes oestrogen defciency in women, thyrotoxicosis, acromegaly, carcinoid syndrome and phaeochromocytoma. General practitioners have generally excluded all the common causes of secondary hyperhydrosis by the time a referral is made. Endocrinologists are then left with exclusion of rarities and, of course, the reality is that endocrine investigations are invariably unremarkable. Although sweating is a recognised symptom of carcinoid syndrome and phaeochromocytoma, in practice these conditions rarely (if ever) present with this symptom in isolation and usually their diagnoses are made in other contexts. In many people with unexplained secondary hyperhydrosis, there is a prior history of significant weight gain. Treatment of unexplained hyperhydrosis is challenging. Usually by the time of referral, simple measures (such as lifestyle change and anti-perspirants) have already been explored. Botulinum toxin injections and iontophoresis (with or without glycopyrrolate) can be very effective for axillary and palmar/plantar hyperhydrosis respectively. Surgery and microwave ablation therapies are also available. Anti-cholinergic agents (such as propantheline and oxybutynin) can be tried for generalised hyperhydrosis, but their efficacy is often limited by side effects. Beta-blockers and clonidine are also sometimes used.