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 WHAT IS ITCH (PRURITUS)
Everyone knows what itch is, but it is difficult to define. Itch
(pruritus) is a sensation, a stimulus that causes you to scratch the itchy area. Originally, it was an ancient defence mechanism in humans and animals: if something causes an itchy or tickling sensation on the skin, it could be a mosquito, a flea, a parasite, or something that could cause an allergic reaction or irritation, and it must be removed. The itch stimulus triggers a reflex, the itch reflex, and we automatically start scratching, even in our sleep. Of course, it becomes a problem when there is a constant itching sensation when there is nothing wrong and no reason to scratch anywhere.
Itch can be very annoying, a nightmare. It
can dominate and disrupt your whole life. Children
with itch cannot sleep. Adults go 'crazy with itching'. Itching is worse than pain is a well-known saying.
Itching can occur with certain skin conditions, such as dry skin, eczema, or psoriasis. In these cases, there are also visible abnormalities. But it can also occur without any visible changes to the skin. The medical term for itching is
pruritus. If skin disorders are
present, such as itchy bumps, the term prurigo is used.
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prurigo nodularis |
prurigo nodularis |
WHAT ARE THE CAUSES OF ITCHING?
Dry skin
Dry skin can cause itching. This is particularly common in older people, but also in people with atopic eczema.
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dry skin |
eczema (atopic dermatitis) |
An itchy skin condition
There are many skin diseases that cause itching. The best-known examples are eczema, psoriasis, and hives (urticaria). Fungal infections with Candida can also cause itching.
A parasitic infection
There are skin parasites that can cause severe itching, such as scabies mites. However, parasitic infections contracted in the tropics, such as intestinal worm infections, can also cause itching. The parasites cause an allergic reaction, which causes the itching.
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scabies |
scabies |
Insect bites
All kinds of stinging insects can cause itching. Not only mosquitoes, but also
midges, horseflies, fleas, mites, and bugs can sting and cause itchy bumps. Sometimes the reaction persists for a long time (persistent insect bite).
Medications
Many medicines can cause itching. Check the package insert to see if this is mentioned as a side effect. But even if it is not mentioned, the medicine may still be the cause. Sometimes you can find information on the internet by searching for the name of the substance in the medicine in combination with keywords such as itch, pruritus, prurigo, allergy, allergic reaction, rash, etc. The only way to find out whether the medicine is playing a role is to stop taking it (for at least 2 months) or replace it with a medicine from a completely different group.
Internal diseases
Itching can occur with an internal disease. There are many internal conditions that can cause itching. However, it is rare for an internal disease to be found as the cause of itching in someone. It is wise to investigate chronic unexplained itching further, usually just with a blood test, to see if there could be an internal disease as the underlying cause. The
list of internal diseases includes:
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Haematological disorders
(blood diseases), both benign (polycythaemia)
and malignant (lymphomas, leukaemia). |
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Uraemia (kidney failure.
When the kidneys are no longer functioning
properly, waste products accumulate and
cause itching. |
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Icterus (jaundice), caused
by a liver that is not functioning properly.
In this case, waste products also
accumulate, causing itching. |
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Diabetes. Later studies
showed that diabetes does not cause itching
very often, although it can sometimes cause
it indirectly due to the medication that
diabetes patients take, or fungal infections
of the skin, which they are slightly more
prone to. |
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Psychological factors. |
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Anaemia, including iron
deficiency. |
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Senility (old age). Older
people often have dry skin, and dry skin can
cause itching. |
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Toxicoderma (a skin
reaction caused by medication). |
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Ancylostoma (a worm
infection), and other parasitic infections,
tropical infections, and diseases such as
scabies, lice, fleas, etc. |
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Thyroid diseases. |
Cause unknown
Unfortunately, no cause is often found for chronic itching. This is very frustrating, not only for you but also for your doctor. At some point, when all possible causes have been thoroughly investigated and ruled out, you will have to accept that it is a chronic and unsolvable problem and look for treatments that alleviate the itching (symptom relief).
Psychological factors
Itching can certainly be psychological. Some people start itching just by reading about it (this brochure, for example, or a brochure about scabies). Healthcare providers who have admitted a patient with scabies without knowing it all start itching acutely when they hear the diagnosis.
Itching, whatever the cause, often starts at the end of the day, when we are sitting quietly on the couch. Or at night in bed. Distraction helps. Doing something else reduces the itching. The other stimuli
make that we pay less attention to the itching stimuli.
Itching can also occur in patients with psychological problems. It often happens after a serious event (death, divorce, dismissal, etc.), sometimes due to stress, depression, or a psychiatric disorder. Itching can also be a side effect of medications prescribed for psychological complaints.
Neurological causes
Apart from the psychological effects mentioned above, itching can also have a neurological cause: a disturbance in nerve conduction or in the brain causes an itching sensation to be perceived without anything actually being wrong. The itching seems to be felt in the skin, but there is something wrong with the nerve. An example is a condition called
notalgia paresthetica. This causes an itchy spot on the back, often just below the shoulder blade, and is caused by irritation of a nerve. A similar condition is called
brachioradial pruritus, in which nerves are pinched near the brachioradialis muscle.
Chronic scratching
If you have a habit of scratching the same spot all the time, or do so as a result of stress, an itchy spot with thickened skin (as a result of scratching) will develop. This spot will continue to itch and scratching will only make it worse. This is called
lichen simplex chronicus. These types of itchy spots are often found on the wrists, ankles, or neck (typical areas that are easy to reach), but they can also be found on the genitals and around the anus. Itching around the anus (pruritus ani) can also have other causes.
Pregnancy
Itching is common during pregnancy (affecting around 50% of pregnant women). Skin abnormalities may also develop (itchy bumps, hives, rashes, blisters). These are called pregnancy dermatoses (itchy skin abnormalities that develop during pregnancy).
HOW IS ITCHING TREATED?
Ideally, a clear cause for the itching can be found, which can then be eliminated with a simple treatment, after which the itching will disappear. Sometimes this is possible, for example if the itching was caused by a medication that can be stopped, or by scabies, which can then be treated. Unfortunately, it is very common that no cause can be found. The only thing left then are treatments and measures that alleviate the itching.
General advice:
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Try not to scratch, as
scratching provides temporary relief but
ultimately only makes it worse. |
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Apply something to the area
instead of scratching. |
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If you really can't help
yourself, scratch through a layer of
clothing. Try replacing scratching with
gently tapping the skin, pressing with your
fingertips, or lightly squeezing. |
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Keep your nails short and
clean to limit damage if the urge to scratch
becomes too strong. |
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If the itching is
severe, find a distraction and try to focus
on something else. |
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Prevent scratching at
night: use cotton gloves or something else
to cover the nails. For babies, there are
also special baby mittens and cotton and
silk pyjamas (anti-scratch suits). |
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Keep the skin moisturized,
prevent dryness, and treat eczema or
psoriasis properly. |
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Avoid things that can dry
out the skin: alcohol on the skin, showering
too often or too hot, using too much soap,
heat, sauna. |
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Avoid things that can
irritate the skin, aggressive products,
perfumed detergents and toiletries, itchy
sweaters, sunburn. |
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Avoid strongly spiced
meals, large quantities of hot drinks, and
alcoholic beverages. |
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Avoid stress. |
Treatment with topical products to be applied to the skin.
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Creams, ointments,
moisturizing lotions. The pharmacy has
products such as cetomacrogol cream, lanette
cream, the oilier vaseline-cetomacrogol
cream, or vaseline-lanette cream. But these
do not always have to be prescription
products. There are various reputable brands
that make excellent skin care products that
you can buy at the supermarket or drugstore. |
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Menthol creams and lotions. |
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Creams containing
capsaicin. Capsaicin is the burning
substance in chili peppers. It creates a
sensation that suppresses the itching. |
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Lidocaine-containing
products. Lidocaine has a numbing effect,
but can cause side effects if used
excessively. |
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Zinc oxide. Zinc oxide
relieves itching, protects the skin, and has
a cooling effect. It is available without a
prescription. It is white, which can be a
disadvantage from a cosmetic point of view.
Zinc oxide is available in the form of
lotion, ointment, paste, salve, and cream.
Zinc oxide lotion is suitable for large
areas (e.g., chickenpox). The water in the
lotion evaporates, giving the lotion a
cooling sensation and relieving itching. The
solid substance (powder) from the lotion
remains as a layer on the skin, so do not
use the lotion on wounds. Zinc oxide lime
water ointment (ZOK ointment) and zinc oxide
ointment are used for weeping skin
conditions, and zinc oxide paste and
ointment for dry skin conditions. Zinc oxide
cream is used for eczema in skin folds and
diaper rash. |
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Corticosteroid creams or
ointments. |
Light therapy
Light therapy with UV-B or broad-spectrum light (see leaflet on light therapy) is also an effective treatment for certain forms of chronic itching.
Treatment with tablets, medicines that you take orally
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Antihistamines. These are
anti-itch tablets that are also prescribed
for hives and hay fever. These medications
cause few side effects and sometimes help,
but unfortunately not always for itching. |
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Gabapentin. |
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Activated charcoal. |
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Prednisone. |
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Cyclosporine. |
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Antidepressants. These
drugs interfere with the transmission of
itch signals via the nerves. |
Others
In the case of insect
bites or contact with stinging nettles, dabbing with
natural vinegar can provide relief. Some patients
find a back scratcher useful, but be careful not to
damage the skin (and scratching only helps
temporarily; it usually makes things worse). A cold
compress on the itchy area, such as a slightly damp
washcloth or towel that you first place in the
refrigerator for a while, or a cold pack wrapped in
a cloth or washcloth, can provide relief.
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