Hyperhidrosis and Anhidrosis at a Glance
- Primary focal (essential) hyperhidrosis:
- Affects over 6 million young people worldwide.
- Excessive palmar sweating affects quality of life.
- Effective treatments (stratified to match the severity) include topical agents, iontophoresis, oral anticholinergics, and botulinum toxin.
- Endoscopic thoracic sympathetic surgery is a last-line choice for severe hyperhidrosis.
- Localized, large areas of hyperhidrosis may be compensatory.
- Clue to loss of sweating elsewhere.
- Determine location of sudomotor lesion and underlying cause by thermoregulatory sweat testing combined with direct and axon reflex sweat evaluation.
- Patterns of anhidrosis provide objective evidence of small nerve fiber and/or eccrine gland involvement in many neurologic and dermatologic disorders.
- Analysis of sweat composition continues to be diagnostic in cystic fibrosis.
- Determination of sweat-derived antimicrobial peptides may provide evidence of impaired innate defense in skin disorders such as atopic dermatitis and neutrophilic eccrine hidradenitis.
Disorders of eccrine sweating can occur for many different reasons, including dysfunction of the thermoregulatory centers in the brain's central autonomic network, changes in the spinal sympathetic preganglionic, ganglionic, or postganglionic neurons/axons or in the muscarinic (M3) cholinergic synapse on sweat glands. Abnormalities of eccrine sweat formation by the secretory coil and sweat ductal cells may occur or ductal disruption or occlusion may develop, preventing delivery of sweat to the skin surface.
A review of the normal anatomy and physiology of eccrine sweat glands and sweating may be found in Chapter 83. This chapter focuses on neurologic and dermatologic disorders that cause focal or generalized abnormalities of sweating, highlighting an exciting interface where disorders are better understood, diagnosed, and treated based on recognition of the integrated function of nerves, skin, and the immune system (Fig. 84-1). There are a variety of techniques that can be used clinically and in research of sweating that are discussed online. Table 84-1 is a comprehensive table based on disorders with increased or decreased sweating—some diseases are discussed in this text–the others are discussed online. Many are disorders related to nervous system structural, functional and inherited disorders; therefore any patient with a sweating disorder should be evaluated carefully for internal medicine diseases and neurologically by consultants in some cases.
A patient with an acquired idiopathic anhidrosis shows anhidrotic (yellow) and sweating (purple) staining of sodium alizarin sulfonate (alizarin Red S) indicator powder. Punch skin biopsy from an anhidrotic skin site (a) shows marked perieccrine lymphocytic infiltration of sweat gland secretory coils, whereas sweating skin (b) shows normal sweat gland morphology. The presence of perieccrine inflammation prompted immunomodulatory therapy with corticosteroids and pulsed methotrexate and a trial of topical tacrolimus.
Table 84-1 Classification of Disorders of Eccrine Sweating |Favorite Table|Download (.pdf)
Table 84-1 Classification of Disorders of Eccrine Sweating
Primary Focal (Essential) Hyperhidrosis
Palmoplantar, axillary, craniofacial, generalized hyperhidrosis
Secondary Causes ...