Acquired idiopathic anhidrosis: a diagnosis often missed.

BACKGROUND: Acquired idiopathic anhidrosis (AIA) is an uncommon entity characterized by anhidrosis in the absence of any neurologic or sweat gland abnormalities. OBJECTIVE: The aim of this study was to characterize the clinical profile in a cohort of patients diagnosed with AIA at a tertiary dermatologic center. METHODS: We retrospectively evaluated cases seen during a 10-year period. Inclusion criteria included all cases of generalized or partial anhidrosis with no obvious causes, confirmed by provocative starch-iodine sweat test. Ectodermal dysplasias, poral dysfunction from chronic dermatoses, autonomic dysfunction, and drug-induced causes were excluded. RESULTS: Fifteen Chinese patients were diagnosed with AIA, mostly healthy young men with no significant medical or drug history, with variable extent of body surface area involvement. Serum immunoglobulin E, a complete blood cell count, thyroid function test, and antinuclear antibody levels were unremarkable. Anhidrotic areas revealed normal eccrine appendages with mild perivascular and perieccrine lymphocytic infiltrate. There were no neurologic abnormalities. LIMITATIONS: This was a retrospective study. CONCLUSION: Our study shows that AIA seems to be a heterogeneous group with no major dysfunction other than anhidrosis. Proper recognition and evaluation is paramount, especially for at-risk populations, so that appropriate measures on the prevention of heat injuries can be instituted.

Changing the way we diagnose tuberculids with interferon gamma release assays.

Diagnosing tuberculids traditionally requires clinicopathological correlation together with positive tuberculin skin tests (TST) or demonstration of Mycobacterium tuberculosis (MTB) DNA by polymerase chain reaction (PCR). Interferon gamma release assays (IGRA) are new laboratory tests approved for the diagnosis of MTB infection. We describe three patients with tuberculids who had no other clinical feature of tuberculosis (TB) infection and negative PCR of skin biopsies. Their diagnoses were aided by positive IGRA.