Febrile sensation without documented hyperthermia

Specialty: General.

• subjective thermal suffocation
• subjective fever
• perceived body warming without fever

Why it occurs

• Generalized anxiety disorders or panic attacks (sympathetic hyperactivity that generates peripheral vasoconstriction and subjective perception of internal heat with cold or diaphoretic skin)
• Early menopausal transition or perimenopause (dysfunction of the hypothalamic thermoregulatory centers due to fluctuations and falls in estrogen levels)
• Eating disorders or extreme high-protein diets (which temporarily increase the thermic effect of food and basal thermogenesis)
• Consumption of centrally acting substances (caffeine in high doses, nicotine, nasal decongestants with pseudoephedrine or antidepressants)
• Small fiber neuropathy (which alters the transmission of peripheral thermal sensitivity by sending erroneous heat signals to the brain).

Initial workup

Strict home recording of axillary and tympanic temperature carried out with a calibrated thermometer at the time of the febrile sensation, thyroid profile (TSH, free T4), fasting blood glucose, complete blood count, and evaluation of basic cardiovascular autonomic function.

Standard management

• Clonidine — 0.075 to 0.15 mg per day orally in divided doses, an alpha-2 adrenergic agonist that stabilizes the thermoregulatory center in cases of severe vasomotor instability
• Propranolol — 10 to 20 mg orally every 12 hours to control symptoms of sympathetic overactivity and perceived suffocation of anxious origin
• Standardized extract of Cimicifuga racemosa (40 mg per day orally as a phytotherapeutic modulator of climacteric hot flashes if that is the cause).