Archive for category Allergies

How to Best Diagnosis Allergies in Adults

What is an Allergy?

All of us are familiar with the word allergy, but very few of us know that every one of us have allergies. We come to know about it only when we start the signs and symptoms. All of us have one question in common, that, why a person suffering with any type of allergy is administered with the same compound Medicine?

Here’s the answer: When our immune system over reacts to substances that are usually not harmful, that means you developed a particular allergy to it. In fighting what it identifies as an invader, the immune system produces a chemical called Histamine, which can provoke sneezing, itching, and other symptoms associated with allergies.

Common form of Allergies:

Hay fever is the most common form of allergic reaction, affecting most of them. Pollen, bits of animal skin (called dander), household dust, and molds are the other forms of allergies.

Food allergies which are relatively uncommon are mostly found among children and are often outgrown by the age of three. The foods that most frequently known to cause allergies are: nuts, eggs and milk. Sea food and peanuts tend to produce the most serious and dangerous reactions that sometimes turn out to be fatal but can be easily retrieved with prompt treatment normally with an injection adrenalin

Allergies to Drugs may often lead to anaphylactic shock. Drug which has shown to be allergic to most of them is Penicillin.

Signs and symptoms include:

Hay Fever – Frequent sneezing, itchy or watery eyes, running or stuffy nose, itching of the back of throat or on roof of the mouth.

Allergic asthma - Sneezing, coughing, in some cases difficulty in breathing.

Food Allergies - Outbreaks of irritated,itchy red, or bumpy skin, stomach ache and or frequent indigestion. Read the rest of this entry »

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The Biology of House Dust Mites and Dust Mite Allergies

House Dust Mites (HDM) are a major source of allergen and found in temperate and humid areas. There is widely published data that shows how House Dust Mites avoidance can reduce exposure to allergens. This article looks at the properties of house dust mite and recommendations for reducing HDM in the home.

Biology of the house dust mite

House Dust Mites are arachnids not insects and related to ticks and spiders such as daddy long legs. Thirteen species of HDM have been found in dust however the two which are the most common and are the main source of the HDM allergen are Dermatophagoides farinae and Dermatophagoides pteronyssinus from the family Pyroglyphidae. The life cycle of the HDM Dermatophagoides pteronyssinus consists of 5 stages. An adult mated female will lay 40 – 80 eggs in her lifetime, when the egg hatches a six legged larva emerges. There are two nymphal stages (which feed and moult before an eight legged adult is developed. The adult HDM has a mouth-like appendage and no eyes or antennae. The duration of the cycle is usually one month and dependent on the climate, ideally 25°C and 75% RH. An adult HDM can live for one to three months under favourable conditions.

Their translucent body is 300µm – 400µm in length and only visible under a microscope with the faecal pellets ranging from 20µm – 50µm, it is estimated that the HDM can produce 20 pellets per day. HDM are ~75% water by weight and therefore need to absorb water from the water vapour in the air making relative humidity (RH) a critical factor for survival.

Dust Mite Habitat

HDM primarily feed on organic detritus such as flakes of shed skin, other nutrients are provided by animal dander, pollen, bacteria and mould. HDM survive and reproduce the best in soft furnishings such as carpets with long pile, bedding and plush toys, which contains a large supply of their food source, this stable environmental dwelling is best provided by homes. Indoor humidity is very important and when it is less than 50% they are unable to maintain their water balance and are more susceptible to desiccation.

The HDM selects food that has been pre decomposed by fungi which reduces the fat content of the skin cells. The fungi in turn are using the house dust mite faeces and skin cells as a source of nitrogen (Woodcock et al. 2006) which forms a minute ecosystem in their environment.

Dust Mite Allergies

Allergy is a response of the human immune system to a foreign protein substance (allergen). A HDM allergy is the result of a hypersensitive immune system response to the mite faces. Faecal pellets are easily airborne and when they become suspended in the air they can be inhaled, the allergic reaction will cause sneezing, wheezing, headaches, coughing, eye irritation, fatigue or dizziness and are confirmed as a major trigger for acute asthma attacks in sensitive individuals. Roughly 1-2 % of the world population (65-130 million people are allergic to house dust mites (Collof, 1999) Read the rest of this entry »

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