title: Clinical differentiation of primary from secondary hyperhidrosis.
abstract: BACKGROUND
  Hyperhidrosis (HH) is excessive sweating that may be primary (idiopathic) or secondary to medication or disease. Clinical features supporting primary or secondary etiology have not been well documented.
  
  
  OBJECTIVE
  To identify clinical and demographic features predictive of a diagnosis of primary versus secondary HH.
  
  
  METHODS
  A retrospective chart review was conducted over a 13-year period (1993-2005) of all patients (children and adults) seen at a university-based outpatient dermatology department with an International Classification of Diseases, 9th revision diagnosis code for HH (N = 415).
  
  
  RESULTS
  Three hundred eighty-seven patients (93.3%) had primary HH (PHH); 28 patients (6.7%) had secondary HH (SHH). SHH patients were older (39.0 ± 18.6 years vs 27.3 ± 12.3 years) with more frequent onset at age older than 25 years (55% for SHH vs12.1% for PHH; odds ratio [OR] 8.7; 95% confidence interval [CI] 3.5-21.4; P < .00001 for each). SHH was more often unilateral/asymmetric (OR: 51; 95% CI: 12.6-208), generalized (vs focal; OR: 18; 95% CI: 7.3-47.6), and present nocturnally (OR: 23.2; 95% CI: 4.3-126; P < .00001 for each). Of SHH cases, endocrine disease accounted for 57% (including diabetes mellitus [11], hyperthyroidism [4], and hyperpituitarism [1]). Neurologic disease accounted for 32% (including peripheral nerve injury [3], Parkinson's disease [2], reflex sympathetic dystrophy [2], spinal injury [1] and Arnold-Chiari malformation [1]). Malignancy (pheochromocytoma), respiratory disease, and psychiatric disease were each represented once. Compared to other secondary causes, asymmetric HH favored neurologic disease (OR: 63; 95% CI: 4.9-810); P = .0002).
  
  
  CONCLUSIONS
  Results were obtained from a single, university-based population.
  
  
  CONCLUSIONS
  On the basis of these data, the diagnostic criteria for PHH were assessed statistically. Criteria include: excessive sweating of 6 months or more in duration, with 4 or more of the following: primarily involving eccrine-dense (axillae/palms/soles/craniofacial) sites; bilateral and symmetric; absent nocturnally; episodes at least weekly; onset at 25 years of age or younger; positive family history; and impairing daily activities. These criteria discriminate well between PHH and SHH (sensitivity: 0.99; specificity: 0.82; positive predictive value: 0.99; negative predictive value: 0.852) and may facilitate optimal clinical management.
authors.affiliation: Department of Dermatology, University of Iowa, Iowa City, Iowa, USA. hobartwalling@yahoo.com
authors.forename: Hobart W
authors.initials: HW
authors.lastname: Walling
mesh_terms: D000293:Adolescent; D000328:Adult; D003937:Diagnosis, Differential; D004700:Endocrine System Diseases / Q000150:complications*; D005260:Female; D006801:Humans; D006945:Hyperhidrosis / Q000175:diagnosis* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications*; D009422:Nervous System Diseases / Q000150:complications*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013546:Sweating; D055815:Young Adult