Itchy Skin

Inspired by last Friday’s AMR case, I thought I’d write an overview of the causes of pruritus, particularly the causes that DON”T go along with a rash (because I hate rashes? Nah).  You can organize these causes in a few ways, but I like to think of them based on the big categories of: dermatologic, systemic disease, neurologic, and psychogenic.

Only takes a few of these guys to set off some serious itching


Most dermatologic etiologies are going to have an associated rash, but it may be subtle. Here are a few where you make have to look closely:

  • Xerosis: The most common cause of generalized pruritus, just plain old dry skin. Common in winter, often can tell skin is try just by feeling it.
  • Scabies: Regular scabies, not the Norwegian kind discussed in AMR, may not have much of a rash associated. Sometimes you can see a burrow, but rarely. I learned that the itching is a delayed hypersensitivity reaction, and may not appear for weeks after infestation.
  • Atopic Dermatitis: Think of this in a patient with other allergic phenomena (rhinitis, conjunctivitis), sx at an early age, and a family history of allergic disease. Patients also have allokinesis, when an innocuous stimuli, like temperature changes or clothing, induces itching.
  • Contact dermatitis: there are two kinds of contact dermatitis. Irritant contact dermatitis (like that caused by poison ivy) occurs when an irritant directly damages the skin.  There is often a rash in this instant.  Allergic contact dermatitis occurs when the irritant induces an allergic response. The rash here may be diffuse and obvious, or may be more subtle. Ask about anything that comes in contact with skin, including soaps, lotions, and laundry detergent.

Systemic Disease

  • Cholestasis: The first thing we think of, but pretty rare. Most commonly starts in the palms and soles before becoming more generalized. Disorders that cause cholestasis include: Primary biliary cirrhosis, cholestasis of pregnancy, viral hepatitis, and anything that causes obstructive jaundice.
  • Renal disease: We think about this in uremia, but it is actually common even in dialyzed patients. Worse at night or after a dialysis session,
  • Malignancy/hematologic disorders: More often with hematologic malignancies than with solid tumors. Think of: Hodgkin’s disease, Polycythemia vera (worse in water), Carcinoid (thank you, histamine), and cutaneous T cell lymphoma. Patients without a diagnosis for their pruritus may be at increased risk for malignancy.
  • Thyrotoxicosis: cause you can’t have a list without thyroid on it. Actually, a fairly common sx of Graves disease.  hypothyroidism can cause xerosis, which itches
  • Connective Tissue Disease: Common with dermatomyositis and scleroderma in particular.

Brachioradial pruritus


Small fiber neuropathy may be associated with pruritus, so anything that causes neuropathy could lead to itching, including diabetes.  These are typically localized to the affected area, however.

  • Post herpetic neuralgia: Up to 50% of patients with post herpetic neuralgia experience this as itching rather than pain.
  • Notalgia Paresthetica: Itching on the upper back, perhaps due to trapped nerve fibers in the T2-T6 nerve roots. Unilateral, near the medial or upper border of the scapula.
  • Brachioradial pruritis: Itching of the proximal dorsolateral forearm, but may extend up to the upper arm or even trunk. Feels better with ice application. Similar to notalgia paresthetica, this may be related to nerve root entrapment in C5-C8, but also may have something to do with sun exposure.
  • MS: Compared to the rest on this list, MS is more likely to cause generalized pruritus. Typically a relapsing, remitting type course that mirrors the rest of the disease.


  • Psychogenic excoriation: Skin is normal, but affected individuals pick and scratch at it. Lesions are all within reach of the patient, and may be precipitated by psychologic stressors.
  • Delusional parasitosis: Patients experience a firm, fixed belief that they are infested by parasites, despite a lack of evidence of infestation.  This may be secondary to another psychiatric disorder, or may be the primary disorder itself.
  • No matter the underlying etiology, pruritus may get worse under emotional stress.

For many, the itching itself causes emotional stress. It impacts sleep, work, relationships. Relief can really improve your patient’s quality of life, plus you may uncover a systemic disease earlier.

If you are itching after reading this post, that is probably psychogenic itching. Good luck!


Love your clinic

Thanks to everyone who came out and participated in noon conference today.  I love clinic and love talking about it- so thanks for indulging me. The full slide deck is on medhub for the locals. But here are the highlights of the discussion.  I would love to hear more from you in the comments.  Chime in!

Communication is the key

As I said, the relationship is the key.  The key to patient satisfaction, physician satisfaction, compliance, negotiating agendas, not getting sued, working in teams, and really just getting out of bed in the morning.  The effort that you put into learning about your patients, listening to their stories, and even hearing about their grandkids will be rewarded many times over.  Plus it’s really interesting. I have a patient who was a civil rights foot soldier. Another one ran away and joined the circus.  Another plays the fluglehorn.  Your patients have these stories too, you just have to find out.

A Fluglehorn, in case you were wondering

Negotiating agendas

You can’t cover it all at every visit, and you will go crazy if you try. Know what you want to cover before you go in, and know what you are willing to give up if your patient surprises you with something. And to minimize the last minute surprises, try to give your patient the chance to speak up right off the bat.  I recommend giving time to the patient to go through their list without a lot of comment or questioning on your part. Just get the list first, then you can negotiate the top few things to cover.

Not the best attitude when negotiating agendas.

Billing in the Clinic

Billing in medicine is all about the note. We are paid for thinking and for taking excellent care of patients, and the only way that anyone knows that we are doing either is to look at the note. There are three parts of the note: History, Physical, and Medical Decision Making (aka Impression and Plan). You always need to document the Medical Decision Making, but for a return patient, you can skip either history or physical. Yep, you just need 2/3 parts.

Challenging patients

As much as I love most people, I don’t get along with everyone. When a patient and I don’t see eye to eye on something, and can’t move past it, it is hard not to let emotions get in the way. If the relationship is going to continue, however, you have to figure out a way past it. Acknowledge (to yourself) the frustration, own it, and then take a deep breath and plunge in. I find that I pay extra attention to my decisions to be sure that I am being objective and fair to the patient. The guiding question is, “What is the right thing for this patient?”  Oftentimes, that is you- since you are such a great primary care MD. Other times, that might be to find someone different to help or to take over care. Just be sure you are making that decision with their, not your, best interests in mind.

A great message, even if it didn’t come from a chief resident.

The big picture here, is think of your clinic as another place to learn medicine, practice communication skills, and meet some interesting folks. You don’t want to miss it.

Clinic is just like this, with better lighting.