Nettle rash (also known as urticaria, hives or
welts) is a raised, red, itchy rash that appears on the skin.
The rash can vary in shape and size. It can be very itchy and usually
goes away within 24 hours. Nettle rash may occur repeatedly or as a
single episode.
Cause-
In about 90 per cent of cases there's no apparent cause. Sometimes,
however, it's possible to identify the cause of the nettle rash. It
most commonly appears to be because of an allergic reaction.
Any of the following may trigger symptoms:
A particular kind of food that causes an allergy. Eggs,
nuts, strawberries and seafood are some of the common culprits.
contact with pollen or fungal spores
medicines, most commonly, non-steroidal anti-inflammatory
drugs (NSAIDs), antibiotics, and ACE-inhibitors
insect bites
infections, which may be caused by viruses, parasites or
bacteria
contact with plants such as stinging nettles
contact with animals or creatures, such as stinging
jellyfish
physical stimuli, such as feeling cold or warm, sunlight,
water, sweating or pressure
Substances, such as perfumes, preservatives, colorings,
nickel or tar.
Pathophysiology-
Urticaria happens when a trigger, normally an allergen (something that
produces an allergic reaction) causes the body to release histamine, a
protein in our body. Histamine causes tiny blood vessels, known as
capillaries, to leak fluid. The fluid then gathers in our skin and If
swelling occurs around the eyes, lips, tongue, larynx, hands or
genitalia - it's called angioneurotic oedema.causes a rash.
Types-
Acute urticaria usually shows up a few minutes after
contact with the allergen and can last a few hours to several weeks.
Food allergic reactions often fit in this category. The most common
food allergies in adults are shellfish and nuts. The most common food
allergies in children are shellfish, nuts, peanuts, eggs, wheat, and
soy. It is uncommon for patients to have more than 2 true food
allergies. In these cases, the hives may be exacerbated by other
factors, such as those listed under Physical Urticarias below.
Chronic urticaria refers to hives that persists for 6 weeks
or more. There are no visual differences between acute and chronic
urticaria. Some of the more severe chronic cases have lasted more than
20 years. A survey indicated that chronic urticaria lasted a year or
more in more than 50% of sufferers and 20 years or more in 20% of them.
Of course this does mean that in almost half the people it clears up
within a year and in 80% it clears up within 20 years or less.
Drug-induced urticaria has been known to result in severe
cardiorespiratory failure. The anti-diabetic sulphonylurea glimepiride
(trade name Amaryl), in particular, has been documented to induce
allergic reactions manifesting as urticaria. Other cases include
dextroamphetamine, aspirin, penicillin, clotrimazole, sulfonamides and
anticonvulsants.
Physical urticarias are often categorized into the
following.
>>Aquagenic:
Reaction to water (exceedingly rare) >>Cholinergic:
Reaction to body heat, such as when exercising or after a hot shower >>Cold
(Chronic cold urticaria): Reaction to cold, such as ice, cold air or
water - worse with sudden change in temperature >>Delayed
Pressure: Reaction to standing for long periods, bra-straps, elastic
bands on undergarments, belts >>Dermatographic:
Reaction when skin is scratched (very common) >>Heat:
Reaction to hot food or objects (rare) >>Solar:
Reaction to direct sunlight (rare, though more common in those with
fair skin) >>Vibration:
Reaction to vibration (rare) >>Adrenergic:
Reaction to adrenaline / noradrenaline (extremely rare)
Symptoms-
The rash caused by urticaria is characterized by swellings, known as
wheals, on the skin. They are typically pink or red, have a round or
oval shape, and are itchy. They can range in size from a few
millimeters to the size of a hand.
Individual wheals normally fade after a few hours, but can be replaced
by new ones. The wheals can appear on just one part of the body, or
across a large part of it.
Most episodes of urticaria peak between 8-12 hours, then stop after 24
hours. However some episodes can last for several days, or even several
months. Episodes of urticaria that last for more than 6 weeks are known
as chronic urticaria.
Diagnosis-
Clinical diagnosis is made by examination of the skin rash.
The diagnosis of the cause is made after a systematic case history. If
an allergic reaction is suspected a skin test (skin prick test) or a
specific blood test may be needed. A specialist in skin or allergic
diseases should carry out these tests.
It is rare for allergy to be the cause of chronic urticaria so routine
allergy tests are not usually necessary. It may be necessary to rule
out other disorders such as endocrine disorders, malignancy, lupus,
other allergic disorders, etc.
Treatment-
Treatment for acute urticaria is normally not required, as the symptoms
are mild, and the condition normally resolves itself within a few days,
and does not come back.
Chronic urticaria can be difficult to treat. There are no guaranteed
treatments or means of controlling attacks, and some sub-populations
are treatment-resistant, with medications spontaneously losing their
effectiveness and requiring new medications to control attacks.
Most treatment plans for urticaria involve being aware of one's
triggers, but this can be difficult since there are several different
forms of urticaria and people often exhibit more than one type. Also,
since symptoms are often idiopathic (unknown reason) there might not be
any clear trigger. If one's triggers can be identified then outbreaks
can often be managed by limiting one's exposure to these situations.
Role of homoeopathy
Homoeopathic medicines strengthen the natural healing processes of the patient and
helps the body fight against the internal dyscrasia. The medicine is
selected on the basis of a holistic approach, which helps to cure it.