What Causes Humans to Have a Cold Nose?

Cold weather is a likely cause of a cold nose in humans because the nose is typically unprotected in the cold outdoors, according to Ask Dr. Gott. Medical conditions such as hypothyroidism, Raynaud’s phenomenon and a viral respiratory tract infection are also possible causes of a cold nose.

Hypothyroidism occurs when there is an inadequate amount of thyroid hormone circulating in the bloodstream, notes Cleveland Clinic. The condition leads to a slowdown in the body's metabolism, and is typically caused by autoimmune thyroiditis, in which the body's immune system attacks the thyroid gland. Patients with hypothyroidism experience an intolerance to the cold, fatigue, weight gain and forgetfulness. Treatment for the condition includes medications that replace the thyroid hormone in the body, which alleviates the symptoms.

Raynaud's phenomenon is a condition that occurs when the small blood vessels in the body tighten in response to extreme temperature, explains Cleveland Clinic. Parts of the body commonly affected include the fingers, toes, nose, lips and earlobes. Raynaud's phenomenon has a variety of causes and can be a symptom of an underlying condition such as systemic lupus erythematosus and carpal tunnel syndrome. Treatment for the condition involves reducing the severity of symptoms through medications and lifestyle changes.

A viral respiratory tract infection can occur due to a variety of pathogens, including rhinoviruses, coronaviruses and influenza viruses, according to the Merck Manuals. Patients with the influenza virus, in particular, experience sore throats, coughing and gastrointestinal symptoms. Infants and the elderly are more likely to have severe cases of viral respiratory infections, and treatment includes antibacterial drugs, antibiotics, aspirin, corticosteroids and anti-viral drugs.