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Chronic Pruritis

Chronic Pruritis

A recent issue of the New England Journal of Medicine contained an excellent review article on the condition known as chronic pruritis – defined as an itch (either localized or generalized) that lasts longer than six weeks. The problem is more common in women than in men and more common in Asians than other races.
The authors of the review article point out that chronic itch can be as debilitating as chronic pain,
leading to changes in sleep patterns and mood disturbances including anxiety and depression.
The sense of itch is carried on unmyelinated C fibers which overlap with the fibers carrying pain.  Over-stimulation of the brain areas receiving these nerves can lead the brain to overreact to noxious stimuli that would otherwise normally inhibit itch, such as scratching or heat/cold exposure. This brain overreaction can also lead to curious symptoms, such as having intense itching associated with undressing.
There are four primary sources of chronic pruritis:
1. Inflammatory skin conditions
2. Systemic diseases
3. Neuropathic disorders. Believe it or not, these can’t be distinguished by the presence or absence of rash because most individuals with chronic pruritis end up with a rash due to trauma to the skin from scratching.
4. Psychiatric conditions.
The most common skin conditions leading to chronic itch are eczema, psoriasis, dry skin, scabies, contact dermatitis, Lichen planus and insect bites. These are best diagnosed by the patient’s history, the appearance of the skin and perhaps, with a skin biopsy.
The most common systemic diseases to cause itch are chronic kidney disease, liver disease, Hodgkins disease, polycythemia, HIV infection and hyperthyroidism. These conditions are best identified by the patient’s history, examination and lab evaluation.
The most common neuropathic causes are brachioradial pruritis (previously discussed in this newsletter), notalgia parasthetica and post-herpetic itch. In all these cases there is a peripheral nerve that is injured or irritated, leading to the itch signal being sent to the brain.
The most common psychogenic causes are OCD (obsessive compulsive disorder), delusions of parasitosis and substance abuse.
Obviously, the treatment is going to vary greatly depending on the cause of the itch. However, even with an accurate diagnosis the itch may be resistant to treatment. In most cases, keeping the skin moist and hydrated is helpful.
Since the C-Fibers are histamine-activated nerves, the use of sedating antihistamines is also helpful. Because of the brain over-stimulation scenario, anticonvulsants and antidepressants have also proven useful.
Finally, because of the overlap of itch and pain fibers, mu-opiod antagonists have often been of help.
Ramsay Hunt Syndrome and chicken pox

Ramsay Hunt Syndrome and chicken pox

Dear Dr. K:  My aunt has Ramsay Hunt syndrome and her doctor said it was a second bout of chicken pox.  Is that true?
The answer to your question is yes and no. In the strictest sense the answer is no, because your aunt doesn’t have generalized chicken pox, but rather a very localized rash. The answer is  yes because, in general terms, Ramsay Hunt is a special form of shingles which is a reactivation of the dormant chicken pox virus (Varicella zoster).
Shingles gets its name because the Varicella virus breaks out in the distribution or dermatone of a single nerve affecting a localized “shingle” of our skin covering.
Ramsay Hunt is an interesting condition because it has unusual neurologic symptoms, in addition to the typical blistering rash. Typically, the patient’s first symptom is severe unilateral ear pain (before any rash). Other common symptoms include facial weakness or paralysis on the side of the ear pain, and ear problems including tinnitus, hearing loss and vertigo.
The shingles rash appears on the ear pinna, the side of the face and side of the neck under the ear.
This condition is preventable with the Zostavax (shingles) vaccine, and can be treated with an oral antiviral and corticosteroids. The earlier this therapy is started, the better.
So, thanks for your question as it may lead to greater awareness of this very unpleasant condition – and to more early diagnoses.
Narcolepsy

Narcolepsy

Recent research has discovered that narcolepsy is a genetically controlled autoimmune disease. Individuals with the gene HLA-DRz/DQI have a very high risk that their immune system will attack a
part of the brain called the hypothalamus. It is in this brain region that an important neuropeptide called hypocretin is made.
Hypocretin is a very important neuropeptide for maintaining alert wakefulness. If the cells in the
hypothalamus that produce it are damaged or destroyed, narcolepsy occurs.
This condition is characterized by a tendency to fall asleep inappropriately during the day. Other unusual symptoms can also occur, such as cataplexy (sudden loss of muscle tone); sleep paralysis (awakening to find your body paralyzed except for breathing); hypnogogic hallucinations (seeing hallucinations just as you’re falling asleep), and what may seem like absent-minded behaviors (such as driving past your exit on the interstate or putting clothing in the refrigerator).
The lack of alerting effects of hypocretin allow non-REM sleep and/or REM sleep to intrude into wakeful times; hence, the unusual symptoms.
Treating this condition can be very helpful but – as in all medical illnesses – it requires an accurate diagnosis. This is probably best accomplished by a sleep doctor. Unlike sleep apnea, it doesn’t respond to CPAP treatment. The two main treatments are daytime stimulants and methylphenidate, and REMsuppressants such as protriptyline.
Sweet: Mother’s kiss also makes a handy tool

Sweet: Mother’s kiss also makes a handy tool

Whoever said laughter is the best medicine didn’t know about a “mother’s kiss.” As it turns out, a recent case review study of nasal foreign bodies found that a mother’s kiss is the best and safest way to remove the object from the nose of a small child or infant.
Using this technique an adult known and trusted by the child blocks the unaffected nostril and blows into the child’s mouth. The blowing should be gentle at first until the adult feels the resistance caused by closure of the glottis (the top of the windpipe at the vocal cords).  Then the adult blows with more force which will then usually expel the nasal foreign body. If not expelled, the object often moves to the end of the nostril where it can be more easily reached.
The case review study of 154 patients found this technique very successful and worked on a variety of foreign bodies from a doll’s shoe to beads, beans, sausage and a dead bug.  It also avoided trauma caused by instruments in a wiggling child, or the need for general anesthesia.
Yin and yang of inflammation – play opposite roles in infection and serious diseases

Yin and yang of inflammation – play opposite roles in infection and serious diseases

Get an infected cut or sprain an ankle and you will experience the healing benefit of inflammation. However, with the benefit also come the redness, swelling, heat and pain that are inflammation’s hallmarks. Although unpleasant, these symptoms dissipate rapidly and are reassuring that the immune system is doing its job to clear infection and guide repair of damaged tissue.
The journal  Science  had a recent review of inflammation as it pertains to chronic diseases. The review looked at new research in three major areas: Type 2 diabetes, cardiovascular disease and neurodegenerative disease. A common factor to all three is the inability of the immune system to clear away the stimulus that triggers the inflammation. Hence, there is a chronic inflammatory state that causes the disease to progress. In the case of Type 2 diabetes, obesity with the resultant saturated fatty acids is the “nonclearable” stimulus to inflammation which leads to insulin resistance, and thereby elevated blood sugars.  In the case of cardiovascular disease it is apolipoprotein B, containing lipoproteins which can’t be cleared by the immune system. The resulting chronic inflammation can be measured by a test called C-reactive protein, and it leads to laying down of arteryblocking plaque or atherosclerosis. And in the case of the neurodegenerative disease (Alzheimer’s disease, Parkinson’s, prion disease and traumatic brain injury), it is the formation of protein aggregates that can’t be cleared.
In Alzheimer’s the protein that aggregates is B amyloid, and its presence stimulates immune cells unique to the brain called microglial cells. The chronic inflammation leads to loss of brain cells and thus, dementia.  Luckily, understanding these mechanisms is leading to fruitful research. One example is altering JNK molecules. These are the enzymes that cause the diabetes-related inflammation. Drugs to modify these JNK enzymes have proven very successful in curing diabetes in mice models.
Egg-free flu vaccines available soon:

Egg-free flu vaccines available soon:

Dear Dr.: I heard there might be a new flu vaccine that is egg-free.
You’re right. In fact you’re double right as there are two egg-free flu vaccines soon to be available.
The first one is called Flucelvax, produced by Novartis. Canine kidney cells culture is used to grow the virus instead of chicken eggs. Tested in 11,000 patients, this new vaccine was 84 percent effective in preventing influenza.
The second is Flublok, offered by Protein Sciences. This one is produced by taking the gene that encodes for hemagluttinin antigen and injecting it into baculovirus – a virus found in insects – which then produces large amounts of hemagluttinin antigen. (Remember, flu virus has two main targets for vaccination: hemagluttinin and neuraminidase.)
Tested in 4,600 patients, this vaccine was 75 percent effective. Both vaccines are currently recommended only for persons 18 years old or older.
ACE Inhibitors

ACE Inhibitors

Dear Doc: ACE inhibitors do their job well, but cause big problems for some patients
Angiotensin-converting enzyme (ACE) inhibitors comprise one of the safest and most effective treatments for hypertension (elevated blood pressure). They work by inhibiting conversion of angiotensin I to its active form, angiotensin II (which leads to hypertension). Unfortunately, they also inhibit the conversion of the peptide bradykinin to its inactive form. Hence, in some people this can lead to a build-up of the peptide which can cause angio edema.
It is unclear why only .1 percent of the people taking ACE are prone to this side effect, but in that .1 percent the symptoms can be dramatic. They include shortness of breath, swelling of the lips, tongue and larynx and in some cases, abdominal swelling.
Another aspect of ACE angio edema that is a bit confusing is that the onset can occur at any time after the person has started the medicine. For many people it occurs after two or three years of use, which leads people to mistakenly think that something else caused their acute symptoms, such as a recent meal.
When ACE-induced angio edema was first understood, it was thought that a safe alternative for the ACE would be an ARB (angiotensin-receptor blocker); unfortunately, these, too, seem to have the same potential for causing mischief.
Pesticides indicated in increased incidence of food allergies

Pesticides indicated in increased incidence of food allergies

Widely used pesticides and chlorinated water may be contributing to the increased frequency of food allergy.  Researchers at Albert Einstein College of Medicine have found a strong correlation between urinary levels of dichlorophenols and the incidence of food allergy. Both children and adults who had measurable levels of the chemicals in their urine were much more likely to have food allergy. Dichlorophenols are commonly found in household pesticides, those used on fruits and vegetables and also in chlorinated tap water. The researchers felt these chlorine chemicals somehow weaken the body’s food tolerance, thus allowing the allergy to develop.
OJ now known to cause FPIES

OJ now known to cause FPIES

Food protein-induced enterocolitis syndrome (FPIES) has recently been reported to occur from orange juice, a previously unrecognized cause.  FPIES mimics food allergy, but it is not mediated by IgE (Immunoglobulin E), the usual allergic mechanism. It is an acute inflammation of the GI tract, caused by a food protein that leads to nausea, vomiting and diarrhea.  Frequently, affected children become dehydrated and require IV fluids.  The condition is often mistaken for a GI flu until the causal association with a food protein is recognized.  The most common cause for FPIES is cow milk. The diarrhea seen with cow milk ingestion is often bloody and, hence, quite startling to unsuspecting parents of infants who develop FPIES.
Other well-recognized causes: rice and soy protein.  The newly described cause is fruits (including apple, pear and banana) and most recently, orange juice.  Unlike with food allergy, children with FPIES have no rash, angioedema or respiratory symptoms. Also, the reaction (unlike with food allergy which tends to be immediate) is generally delayed two-to-four hours after ingestion of the trigger food. Because FPIES is not a classic allergic condition, it cannot be diagnosed by allergy testing.  The best method for diagnosis is recognizing the suspected food as an antecedent to the symptoms. Also, oral food challenge tests can be conducted to confirm the diagnosis.
Popular foods, pancake batter linked to pesky syndromes

Popular foods, pancake batter linked to pesky syndromes

Food ingestion anaphylaxis caused by mites is a newly described syndrome, as detailed by the World Allergy Organization in this month’s Journal of Allergy and Clinical Immunology. Until recently mite allergy was best recognized as a major cause for allergic rhinitis and asthma via the inhalation of the microscopic mites. Millions of allergy sufferers actually receive allergy shots for this mite allergy.  Over the years occasional case reports would appear in the medical literature about airway anaphylaxis;  that is, sudden and severe closure of the airways due to an inordinate inhalational dose of mite, such as from spilling a vacuum cleaner bag. But until recently, there had never been reports of anaphylaxis from the ingestion of mites.
The new syndrome has been dubbed oral mite anaphylaxis (OMA), or also “pancake syndrome,” because the primary source of ingested mites is from wheat flour contaminated with mites — and for some reason, this occurs most often in pancake mix.  The syndrome occurs primarily in warm, tropical or sub-tropical locations where temperature and humidity favor the proliferation of mites in certain foods.  In some cases the wheat itself was mistakenly assumed to cause the reaction because the presence of mites was not initially suspected.  Also, the patient may live in a northern clime, but have a reaction from wheat or flour mix produced in a tropical area.
Unfortunately, cooking does not inactivate the mites in terms of allergenicity.  Other common foods that have been implicated are pizza dough, beignets, polenta, grits and scones.