Cold nose theory has many variables at play

After a winter of wild weather, spring is fully here. That means many of us are heading outdoors. Please play it safe and remember to guard against the sun with hats, long sleeves and sunscreen, and to ease back into physical activities. Balmier weather means ticks and mosquitoes have begun to emerge, so don't forget the bug protection as well.

And now, onward to your questions.

• We recently wrote about intriguing new research that suggests cases of the common cold and the flu spike in winter weather because of the inner workings of the human nose. Specifically, that a crucial first-line immune response becomes less robust when cold weather causes the temperature inside the nose to drop.

This led a reader to ask about specifics. "It's not clear how long it takes for cold weather to cause this effect," he wrote. "That answer might explain the folk knowledge axiom that getting 'cold and wet' has brought on a cold." That's a very interesting thought. Folk wisdom does, indeed, connect becoming chilled with an increased risk of catching a cold.

However, when it comes to this new "cold nose" theory, a lot of variables are at play. These include outdoor temperature, breathing rate, the state of the person's immune system and - it sounds funny but it plays a role - the size of their nose. That makes it difficult to identify the precise length of time it takes for immune response to drop.

• When someone develops an unfamiliar disease or condition, figuring out who to consult can be confusing. We recently heard from a reader facing that dilemma. "I have been diagnosed with CIDP," they wrote. "Which doctor should I be seeing - an internist or a neurologist?"

CIDP refers to a neurological disorder known as chronic inflammatory demyelinating polyneuropathy. It is marked by progressive weakness in the arms and the legs, along with a decrease in sensation in the affected limbs.

CIDP occurs when the myelin sheath, which is the fatty coating that insulates the neurons, becomes damaged. If you've been diagnosed with this disease, a neurologist should oversee your care. In addition to medications that focus on the immune system, treatment includes physical and occupational therapy and the use of orthotic devices.

CIDP requires long-term treatment and management. The National Institutes of Health recommends the GB/CIDP Foundation International as a useful resource. You can visit the website at gbs-cidp.org.

• Several readers have recently written to ask about shampoos for scalp psoriasis. Medicated shampoos, which can ease symptoms such as itchy, scaly and flaky skin, are widely available at your local drugstore. These typically contain coal tar, which impedes skin cell growth and aids in shedding dead skin cells, or salicylic acid, which helps to soften and remove scaly patches.

Be willing to experiment, as it can take trial and error to find the brand that works best for you.

Thank you, as always, for your questions, comments and letters of encouragement. We love hearing from you.

• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.