WO2016055764A2

WO2016055764A2 - Improvements in and relating to allergy testing

Info

Publication number: WO2016055764A2
Application number: PCT/GB2015/052709
Authority: WO
Inventors: Hayley Ogden
Original assignee: Hayley Ogden
Priority date: 2014-10-07
Filing date: 2015-09-21
Publication date: 2016-04-14
Also published as: GB201417741D0; WO2016055764A3; GB2531027A

Abstract

A cartridge (10), comprising a housing (12) defining a recess (22) therein and an absorbent element (14) within said recess (22) on which is held an allergen, which is to be tested on the skin of a person. An applicator (40) for the storage of multiple cartridges (10a) to (10e), and the application of an allergen held in the absorbent element (14) onto the skin of a person. The applicator (40) comprises a substantially tubular housing (41), with a substantially cylindrical compartment (45) within, able to hold multiple cartridges (10a) to (10e). The cartridges (10) are pushed towards an open end (41b) of the housing (41) by a cartridge advancement means (52), and are physically prevented from being ejected by a cartridge retaining means (62), and in this case, a secondary cartridge retaining means (64). The cartridge retaining means (62) and secondary cartridge retaining (64) means can be disengaged by a user in order to eject a lead cartridge (10a) once it has been used. A following cartridge (10b) is then moved to the front of the applicator (40), by the cartridge advancement means (52), ready for the next use. A method for application of an allergen onto the skin of a person by use of an applicator (40) and cartridge (10) is also provided.

Description

Improvements in and Relating to Allergy Testing

The present invention relates to a cartridge for the application of an allergen to a person's skin for the testing of allergies, an applicator for use with said cartridge, and a method of applying an allergen for the testing of allergies, by the use of an applicator and cartridge.

Permanent hair dyes commonly utilise compounds which can induce allergic responses in some people. These responses can include irritant contact dermatitis, commonly referred to as skin irritation, all the way to allergic contact dermatitis, commonly referred to as a 'genuine' allergy, and even more severe reactions. Both these forms of contact dermatitis are caused by contact with a substance to which the body is either irritated, allergic or has developed a sensitivity. Allergic contact dermatitis is accepted to be the most prevalent form of immunotoxicity found in humans.

Symptoms of contact dermatitis can include localised rash or itching, inflammation and skin lesions. Importantly, whilst irritant contact dermatitis generally appears immediately after contact with a substance, allergic contact dermatitis may well take a day or two to reveal any symptoms.

Rarely, an allergy to the substances present in permanent hair dyes can result in hives, and even anaphylaxis in the most severe cases. The most commonly used compound of this kind is paraphenylenediamine, hereinafter referred to as PPD. PPD is supplied as a colourless substance, which is then mixed with an oxidising agent in order to change the colour of the substance, and dye the hair. Other, less common, compounds include para-aminodiphenylamine (hereinafter referred to as PADA), paratoluenediamine (hereinafter referred to as PTDA) or 3-nitroparahydroxyethylaminophenol.

As irritant and allergic reactions to these compounds are known and minor reactions are not particularly rare, it is common practice for hairdressing establishments to administer tests for sensitivities prior to an appointment for permanent hair colouring. Testing normally requires a customer to attend the salon forty-eight hours prior to the colouring appointment, and undergo 'patch testing' whereby small areas of skin have the dye compounds applied to them. The customer is then sent away, and if, within forty-eight hours, there has been a reaction to the dye compound, the customer is disallowed from undergoing hair colouration. Similarly, for home dyeing purposes, there are normally instructions on the packet to put a small portion of the dye on an area of skin behind the ear and leave it for two days, before proceeding to dye the hair, in order that any adverse reaction to the product can be recognised so as to prevent the user from using the product on a larger area.

Importantly, reactions of the kind induced by the compounds in hair dye can also come about through a process known as sensitisation. Whilst the body may not produce a reaction to a compound initially, exposure over a number of periods (for instance, getting ones hair dyed six times over the course of two years) can lead to the body slowly building up a sensitivity to the compound, and therefore exhibiting a reaction upon further application of the compound. Because of this sensitisation problem, each and every time a consumer wishes to use a hair dye, testing for reactions must be done.

When using home hair dyeing kits, this is an inconvenience. Additionally, due to perhaps having to test multiple hair dye products to find one that does not produce a reaction, it can become expensive, especially if the consumer finds that they react to a large number of products. However, in a commercial setting, the customer must be able to find the time to visit the hairdresser twice in the course of less than a week, which, for many, is very difficult, and can also be expensive for the salon and customer.

The present invention seeks to provide an apparatus and a method for overcoming these issues, by way of a testing kit, which can be used whenever necessary.

According to a first aspect of the invention, there is provided a cartridge for the application of an allergen to a person's skin, comprising: a housing, including at least a base, and a perimeter wall upstanding from the base, the perimeter wall defining an end of the housing which is at least in part open, the base and perimeter wall defining a recess; an absorbent element positioned at least partially within the recess; and an allergen in contact with said absorbent element.

The allergen is thus contained in the housing of the cartridge via the absorbent element in a safe and secured manner. The cartridge is also convenient to carry, allowing the user to apply the allergen test as and when required.

Preferably, the cartridge further comprises a retaining rim, protruding from, and extending around at least a portion of, the perimeter wall of the housing. This retaining rim allows easier positioning and retention of the cartridge in a given position. The retaining rim could additionally be at or adjacent to the base. Advantageously, the cartridge also includes a removable cover element which is removably attachable to the perimeter wall to close the at least in part open end.

Preferably, the allergen in contact with the absorbent element is any one of paraphenylenediamine (PPD), para-aminodiphenylamine (PADA), paratoluenediamine (PTDA) or 3-nitroparahydroxyethylaminophenol, which are the three most commonly used allergens present within hair dyes, both commercially and in home-use.

It is preferable for the absorbent element to be expandable in order to become exposed, ready for application.

According to a second aspect of the invention, there is provided an applicator for the application of an allergen to a person's skin, comprising: an elongate housing having a main body with at least one open end, the main body including a cartridge compartment extending along at least a portion of the longitudinal extent of the housing; at least one cartridge of the first aspect of the invention which is removable receivable in the cartridge compartment of the housing; a cartridge advancement means for the advancement of cartridges within the cartridge compartment towards the open end; and at least one cartridge retaining means at or adjacent to the open end for preventing or inhibiting unintentional ejection of a said cartridge at the open end

The applicator device thus assists with application of the allergen in the cartridge on a user in a controlled manner. As each cartridge carries a predetermined amount of allergen, it ensures a measured amount of allergen is applied each time and thus the safety of the user. The applicator is able to carry more than one cartridge, allowing the user to use the applicator for multiple allergen tests. The applicator allows simple and efficient testing either by a skilled user or an untrained member of the public. Preferably, the cartridge retaining means prevents unwanted ejection of the cartridge by way of mechanical engagement with a retaining rim of the cartridge. In this way, control of ejection and location can be combined rather than requiring further features.

Advantageously, the cartridge retaining means is movably mounted to the housing, allowing the cartridge retaining means to be forcibly disengaged from the retaining rim.

Additionally, the applicator may further comprise a re-engagement means, for automatically re-engaging the cartridge retaining means after disengagement. Automatic re-engagement would make it harder to accidentally eject multiple cartridges, ensuring ease of use. Advantageously, the cartridge retaining means includes a detent.

Preferably, the or each cartridge retaining means is a pivotable retaining member, thereby allowing the cartridge retaining means to be disengaged by way of pivoting of the pivotable retaining member by the user.

Furthermore, the or each pivotable retaining member may be pivotable about an axis lying tangential or substantially tangential to the outer surface of the housing.

Preferably, the applicator additionally comprises a secondary cartridge retaining means for preventing the simultaneous ejection of more than one cartridge. The secondary cartridge retaining means negates the necessity of the user to manually reengage the cartridge retaining means in order to prevent multiple ejections. Beneficially, the first said cartridge retaining means and secondary cartridge retaining means are integrally formed as one element, in order to lower the number of components necessary for manufacture. Preferably, the disengagement of the said first cartridge retaining means automatically engages the secondary cartridge retaining means with a following cartridge, for the purpose of allowing the lead cartridge to be ejected from the housing, whilst keeping the following cartridges in situ. Advantageously, the said first cartridge retaining means and secondary cartridge retaining means can be positioned at or adjacent to opposing ends of the pivotable retaining member. This positioning would allow a force applied to one end of the pivotable retaining member to engage one and disengage the other of the cartridge retaining means and secondary cartridge retaining means, thus requiring only one movement from the user to carry out both actions.

Preferably, the cartridge advancement means is or includes a spring positioned within the compartment of the housing, whereby the axis of the spring is parallel or substantially parallel to the longitudinal extent of the housing, whereby extension of the spring is towards the open end of the housing. Advantageously, the cartridge retaining means may be positioned such that the at least one cartridge at least in part protrudes from the end of the housing. Thus, the absorbent element of the cartridge will be in a position whereby it is easily applied to the user once exposed.

Preferably, the applicator further comprises a removable cap for closing the open end of the housing and for covering the said at least one cartridge.

Optionally, the applicator further comprises an access aperture through a perimeter wall or a closed end of the housing, wherein the access aperture permits loading of the cartridge or cartridges.

Advantageously, the access aperture is located at the opposing end of the housing to the cap. This positioning would allow the cartridges to be loaded at one end of the housing, pass longitudinally within the housing, and then be expelled from the opposite end, thus maintaining the position of each cartridge within the housing in the order of loading. Preferably, the applicator further comprises a secondary cap, releasably affixable to the access aperture, for closing the access aperture. This closing prevents cartridges falling out of the access aperture.

The applicator may further comprise at least one window in the housing, to allow a user to view the recess. The provided window or windows would allow a user to see easily what cartridges are present within the recess, at any time, without having to dismantle the applicator or remove the cartridges.

Beneficially, the applicator may further comprise a gripping portion, situated on an exterior surface of the housing. This gripping portion allows a user to better manipulate the applicator, whilst in use.

According to a third aspect of the invention, there is provided a method of application of an allergen to a person's skin, comprising the steps of: a] providing one or more cartridges comprising an absorbent element upon which there is an allergen, the cartridges being contained within an applicator, wherein at least one said cartridge at least partially protrudes from the applicator; b] exposing the absorbent element of the said protruding cartridge, thereby exposing the allergen; c] orientating the applicator to bring the exposed absorbent element into contact with the skin of a person, thus applying the allergen; and d] ejecting the said protruding cartridge from the applicator.

The above method allows an allergen test to be carried out in an efficient and tidy manner. Application of the allergen can be directed accurately to precise area of skin to be tested and disposal of the used cartridge is quick and straight forward. The method is thus user friendly.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of one embodiment of a cartridge, in accordance with the first aspect of the invention;

Figure 2 is a perspective view of three of the cartridges shown in Figure 1; Figure 3 is a perspective view of one embodiment of an applicator, in accordance with the second aspect of the invention;

Figure 4 is a cross-sectional perspective view of the applicator of Figure 3, loaded with five of the cartridges shown in Figure 1; and Figure 5 is an enlarged cross-sectional perspective view of a pivotable retaining member forming part of the applicator shown in Figure 4.

Referring to Figure 1, there is shown one embodiment of an applicator cartridge 10, forming part of an allergy testing device, and which comprises a housing 12, absorbent element 14, and cover element 16. The housing 12, in this embodiment, includes a circular base 18 and a perimeter wall 20, extending, preferably perpendicularly, from the base 18, thus forming a hollow cylindrical or substantially cylindrical cavity or recess 22 with an open end 23. A retaining rim 24 protrudes outwardly, preferably normal, to the perimeter wall 20 and in this case coplanar to the base 18. The rim 24 extends around the entire circumference of the base 18. Although uniform and uninterrupted, both the rim and perimeter wall may be discontinuous as necessity dictates.

The absorbent element 14 is preferably substantially cylindrical in shape and dimensioned such that the outer diameter of the absorbent element 14 is slightly smaller than the interior diameter of the housing 12 such that, in use, the absorbent element 14 can fit within the recess 22 of the housing 12 as a close or interference fit.

The absorbent element 14 is, in use, slightly longer than the housing 12 such that, when positioned within the housing 12, and longitudinally unconstrained, the absorbent element 14 protrudes slightly out of the end of the recess 22.

The cover element 16 comprises a covering portion 26 and a tab portion 28. The covering portion 26 is again preferably circular in shape to correspond to the housing 12 and is sized in order to be slightly larger than the outer diameter of the perimeter wall 20. Therefore, the covering portion 26 can be easily attached to the housing 12 for storage, for instance, by adhesive heat sealing. The tab portion 28 of the cover element 16 is substantially semi-circular and extends radially outwardly from one side of the covering portion 26, being preferably integrally formed therewith. The tab portion 28 and covering portion 26 are formed from the same piece of material, for instance a laminar metal foil, which must be sufficiently strong such that a force applied to the tab portion 28, parallel to the longitudinal extent of the housing 12, causes the cover element 16 to detach from the housing 12 without the cover element 16 breaking, in order that the cartridge 10 can be prepared for usage.

Figure 2 depicts a series of three said cartridges 10 arranged as if they were loaded into an applicator. The cartridges 10 are in a pre-use arrangement, wherein the cover element 16 is attached onto the open end of the cartridge 10, thus sealing a defined chamber within.

Referring to Figure 3, there is shown a first embodiment of an applicator 40 for use with the cartridge 10 and forming another part of the allergy testing device. A majority of a length of the applicator 40 is a housing 41, which comprises a main body 42. The main body 42 is substantially cylindrical in shape, though with an inward taper towards both ends, resulting in a slightly fusiform structure. One end 41a of the housing 41 is closed, whilst an open end 41b is covered by way of a removable cap 46. The main body 42 itself is hollow or substantially hollow, with walls 41c defining a compartment 45 therewithin. This compartment 45 can be viewed by way of an optional window 44 through the wall of the main body 42. The window 44 preferably extends approximately two-thirds of the way along the longitudinal extent of the main body 42.

Towards the capped end 41b of the main body 42, two pivotable retaining members 48 are preferably provided, opposing one another across the diameter of the main body 42. In this case, each pivotable retaining member 48 pivots about a pivot bar 50, which is substantially half way along the length of each pivotable retaining member 48 and substantially tangential to the exterior surface of the main body 42. The pivotable retaining member 48 is shown in more detail in Figures 4 and 5. Referring firstly to Figure 4, the applicator 40 is loaded with five said cartridges 10a to lOe in end-to-end or series relationship. In this arrangement, the applicator 40 is ready to use, once the cap 46 has been removed. With the foremost cartridge 10a protruding from the end of the main body 42, the cover element 16 is removed from this foremost cartridge 10, and therefore the pre-charged absorbent element 14 expands to be exposed, ready for applying an allergen, such as PPD, PAD A, PTDA or 3- nitroparahydroxyethylaminophenol to a user's skin.

A cartridge advancement means 52 is situated at the closed end 41a of the main body 42, and includes a helical spring 52a, which pushes against the rearmost cartridge lOe. In so doing, the cartridges 10a to lOe are held tightly to one another within the main body 42 and are advanced through the main body 42 when possible, towards the open end 41b.

Whilst in this embodiment the cartridge advancement means is or includes preferably a helical spring, the cartridge advancement means may comprise a different type of spring, or alternatively other means, such as an advanceable platform which may be spring driven or driven by an electric motor.

To prevent premature ejection of the foremost cartridge 10a, the applicator 40 may comprise a pivotable retaining member 48, on one end of which is a cartridge retaining means 62. This cartridge retaining means 62 in this embodiment is a detent, such as an inwardly-projecting tongue or tab 62a, which engages with the retaining rim 24 of the foremost cartridge 10a. The cartridge retaining means 62 is explained in more detail hereinafter with reference to Figure 5.

Although the cartridge retaining means of this embodiment is preferably an inwardly spring-biased detent, a retaining ring or otherwise shaped member may be considered. The cartridge retaining means could also be designed as a pin for engaging with a complementarily shaped hole in each cartridge, or could be any other form of retainer, as long as said retainer is able to prevent the undesired axial movement of cartridges. It is also anticipated that the cartridge retaining means may be mounted to the housing in a way other than by way of a pivotable member. For example, the cartridge retaining means could be movably mounted by way of runners, with or without spring-mounting, or could alternatively be twist-lockable.

As shown in Figure 5, the pivotable retaining member 48 is pivotably attached to an outer surface 42a of the main body 42 by way of a pivot bar or fulcrum 50 which forms part of the housing 41. There is additionally a re-engagement mechanism by way of a second helical spring 66, whereby a radially inner end 66a of the second helical spring 66 rests on the outer surface 42a of the main body 42, underneath a proximal end 48a of the pivotable retaining member 48, and the opposing radially outer end 66b of the helical spring 66 abuts an underside of the proximal end 48a of the pivotable retaining member 48. The helical spring 66 provides a resistive force in order to bias the pivotable retaining member to a default cartridge-engagement position, whilst allowing an external force via a user input to push the pivotable retaining member 48 into a secondary cartridge-release position.

The re-engagement means, whilst in the present embodiment is a helical spring, could also be a torsion spring, compressible elastomer, or other such element.

The pivotable retaining member 48 comprises the cartridge retaining means 62, described above, and optionally a secondary cartridge retaining means 64, which in this case is a further detent in the form of an inwardly protruding tongue or tab 64a extending into the recess or compartment 45 within the main body 42. The first and second cartridge retaining means 62, 64 are situated at opposing ends of the pivotable retaining member 48. The first said cartridge retaining means 62, which protrudes from the distal end 48b of the pivotable retaining member 48 opposite the helical spring 66, engages with the retaining rim 24 of the first or lead cartridge 10a, when the pivotable retaining member 48 is in its default position. This mechanical engagement between the cartridge retaining means 62 and the retaining rim 24 prevents or inhibits the lead cartridge 10a from being ejected from the end of the main body 42. The application of a user force to the sprung proximal end 48a of the pivotable retaining member 48 causes the pivotable retaining member 48 to move to a secondary position whereby the cartridge retaining means 62 is disengaged from the retaining rim 24 of the first loaded cartridge 10. This movement releases the lead cartridge 10a for ejection, whilst simultaneously engaging the secondary cartridge retaining means 64 with the retaining rim 24 of the second or follow-on cartridge 10b.

The engagement of the secondary cartridge retaining means 64 with the retaining rim 24 of the follow-on cartridge 10b prevents or inhibits the ejection of the follow-on cartridge 10b at the same time as the ejection of the lead cartridge 10a. Once the force applied to the pivotable retaining member 48 is released, the helical spring 66 causes the pivotable retaining member 48 to revert to its default position, at which point the secondary cartridge retaining means 64 disengages from the retaining rim 24 of the follow-on cartridge 10b, and the follow-on cartridge 10b moves forwards until its retaining rim 24 engages with the cartridge retaining means 62. This process can then be repeated until there are no more cartridges 10 within the main body 42.

A user would utilise the applicator 40 with the included cartridge 10 in order to apply an allergen to a person's skin, whether that person is the user themselves or another person. In order to use the applicator 40, the user must first remove the cap 46 from the open end 41b of the housing 41. This removal of the cap 46 would result in the lead cartridge 10a within the compartment 45 to be exposed. The cover element 16 which covers the open end 23 of the cartridge 10a must then be removed. This removal of the cover element 16 is made easier by use of the tab portion 28. Once the cover element 16 is removed, the absorbent element 14 would be exposed from the open end 23 of the cartridge 10a. At this point, the applicator 40 can be directed towards, and then pressed onto the skin of a person to be tested, so that the absorbent element 14 contacts said person. The contact will transfer at least a portion of the allergen from the absorbent element 14 onto the skin of the person. In so doing, the allergen application will be complete.

At this point, the proximal ends 48a of the pivotable retaining members 48 can be pressed by the user. This pressing causes the first cartridge retaining means 62 to disengage with the retaining rim 24 of the lead cartridge 10a. The lead cartridge 10a will then be free to be removed or ejected from the main body 42. Releasing the pivotable retaining members 48 disengages the secondary cartridge retaining means 64, as the pivotable retaining members 48 are pushed back into their default position by the respective helical springs 66. The cartridge advancement means 52 then extends, pushing the follow-on cartridge 10b up to the point at which its retaining rim 24 abuts the first cartridge retaining means 62. The follow-on cartridge 10b now becomes the lead cartridge and is ready to be used.

This process can be repeated multiple times, until there are no further cartridges 10 within the compartment 45 of the housing 12. However, to recharge the applicator 40, the pivotable retaining members 48 are simply depressed, allowing new or fresh cartridges to be inserted into the compartment 45 within the main body 42.

Alternatively, it would be possible to allow recharging of the applicator by the addition of an access aperture through the closed end 41a of the housing 41. Such an access aperture would allow cartridges to be inserted such that the order of insertion determines the order of use of the cartridges. The access aperture could then be closed by way of a secondary cap, in order to reseal the cartridge compartment after loading of additional cartridges. Whilst it is preferable that the access aperture at or adjacent to the closed end 41a of the housing 41, the access aperture could also be positioned at any point along the main body of the applicator.

The outer surface of the applicator in the described embodiment is smooth, but could additionally be provided with a gripping portion, composed of a rubber or other such material that provides increased friction between the applicator and the hand of the user. The gripping portion would allow a user to maintain better control over the applicator, due to the increased grip available to the user.

It is thus possible to provide a cartridge containing an absorbent element upon which is deposited an allergen for testing, and an applicator for use with one or more of said cartridges. When loaded within the applicator, the absorbent element can be exposed within the cartridge and applied to a person's skin, thus transferring the allergen. The applicator can house multiple cartridges, allowing the ejection of a cartridge once it has been used and enabling a second cartridge to be automatically positioned ready for a second test. The cartridge and applicator provide a simple means for a user to apply a controlled amount of an allergen, allowing simple and efficient testing, either by a skilled user, or an untrained member of the public.

The words 'comprises/comprising' and the words 'having/including' when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.

Claims

1. A cartridge (10) for the application of an allergen to a person's skin, comprising: a housing (12) including at least a base (18), a perimeter wall (20) upstanding from the base, the perimeter wall (20) defining an end (23) of the housing which is at least in part open, the base (18) and perimeter wall (20) defining a recess (22);

an absorbent element (14) positioned at least partially within the recess (22); and an allergen in contact with said absorbent element (14).

2. A cartridge (10) as claimed in claim 1, further comprising a retaining rim (24), protruding from, and extending around at least a portion of, the perimeter wall (20) of the housing (12).

3. A cartridge (10) as claimed in claim 2, wherein the retaining rim (24) is at or adjacent to the base (18).

4. A cartridge (10) as claimed in any one of the preceding claims, further comprising a removable cover element (16) which is removably attachable to the perimeter wall (20) to close the at least in part open end (23).

5. A cartridge (10) as claimed in any one of the preceding claims, wherein the allergen is any one of: paraphenylenediamine (PPD); para-aminodiphenylamine (PAD A); paratoluenediamine (PTDA); or 3-nitroparahydroxyethylaminophenol.

6. A cartridge (10) as claimed in any one of the preceding claims wherein the absorbent element (14) is expandable in order to become exposed, ready for application.

7. An applicator (40) for the application of an allergen to a person's skin, comprising:

an elongate housing (41) having a main body (42) with at least one open end (41b), the main body (42) including a cartridge compartment (45) extending along at least a portion of the longitudinal extent of the housing (41);

at least one cartridge (10) as claimed in any one of claims 1 to 6 and which is removably receivable in the cartridge compartment (45) of the housing (41);

a cartridge advancement means (52) for the advancement of cartridges (10) within the cartridge compartment (45) towards the open end (41b); and at least one cartridge retaining means (62, 64) at or adjacent to the open end (41b) for preventing or inhibiting unintentional ejection of a said cartridge (10) at the open end (41b).

8. An applicator (40) as claimed in claim 7, wherein the cartridge retaining means (62) prevents unwanted ejection of the cartridge (10) by way of mechanical engagement with a retaining rim (24) of the cartridge (10).

9. An applicator (40) as claimed in claim 8, wherein the cartridge retaining means (62) is movably mounted to the housing (41), allowing the cartridge retaining means (62) to be forcibly disengaged from the retaining rim (24).

10. An applicator (40) as claimed in claim 9, further comprising a re-engagement means (66), for automatically re-engaging the cartridge retaining means (62) after disengagement.

11. An applicator (40) as claimed in any one of claims 8 to 10, wherein the or each cartridge retaining means (62) includes a detent.

12. An applicator (40) as claimed in any one of claims 8 to 11, wherein the or each cartridge retaining means (62, 64) is a pivotable retaining member (48).

13. An applicator (40) as claimed in claim 12, wherein the or each pivotable retaining member (478) is pivotable about an axis lying tangential or substantially tangential to the outer surface of the housing (41).

14. An applicator (40) as claimed in any one of claims 8 to 13, further comprising a secondary cartridge retaining means (64) for preventing the simultaneous ejection of more than one cartridge (10).

15. An applicator (40) as claimed in claim 14, wherein the first said cartridge retaining means (62) and secondary cartridge retaining means (64) are integrally formed as one element.

16. An applicator (40) as claimed in claim 14 or claim 15, wherein the disengagement of the said first cartridge retaining means (62) automatically engages the secondary cartridge retaining means (64) with a following cartridge (10).

17. An applicator (40) as claimed in any one of claims 15 or claim 16 when claim 15 is dependent on claim 13, wherein the first cartridge retaining means (62) and secondary cartridge retaining means (64) are positioned at or adjacent to opposing ends of the pivotable retaining member (48).

18. An applicator (40) as claimed in any one of claim 7 to 17, wherein the cartridge advancement means (52) is or includes a spring (52a) positioned within the compartment (45) of the housing (41), whereby the axis of the spring (52a) is parallel or substantially parallel to the longitudinal extent of the housing (41), whereby extension of the spring (52a) is towards the open end (46) of the housing (41).

19. An applicator (40) as claimed in any one of claims 7 to 18, wherein the cartridge retaining means (62, 64) is positioned such that the said at least one cartridge (10) at least in part protrudes from the end of the housing (41).

20. An applicator (40) as claimed in any one of claims 7 to 19, further comprising a removable cap (46) for closing the open end (41b) of the housing (41) and for covering the said at least one cartridge (10).

21. An applicator (40) as claimed in any one of claims 7 to 20, further comprising an access aperture through a perimeter wall or a closed end (41a) of the housing (41), wherein the access aperture permits loading of the cartridge or cartridges (10).

22. An applicator (40) as claimed in claim 21, wherein the access aperture is located at the opposing end of the housing to the cap (46).

23. An applicator (40) as claimed in claim 21 or claim 22, further comprising a secondary cap, releasably affixable to the access aperture, for closing the access aperture.

24. An applicator (40) as claimed in any one of claims 7 to 23, further comprising at least one window (44) in the housing (41), to allow a user to view the cartridge compartment (45).

25. An applicator (40) for the application of an allergen, as claimed in any one of claims 7 to 24, further comprising a gripping portion, situated on an exterior surface of the housing (41).

26. A method of application of an allergen to a person' s skin, comprising the steps of: a] providing one or more cartridges (10) comprising an absorbent element (14) upon which there is an allergen, the cartridges (10) being contained within an applicator (40), wherein at least one said cartridge (10) at least partially protrudes from the applicator (40);

b] exposing the absorbent element (14) of the said protruding cartridge (10), thereby exposing the allergen;

c] orientating the applicator (40) to bring the exposed absorbent element (14) into contact with the skin of a person, thus applying the allergen; and

d] ejecting the said protruding cartridge (10) from the applicator (40).

27. A method of application of an allergen to a person's skin, the method comprising the steps of:

a] providing one or more cartridges (10) comprising an absorbent element (14) upon which there is an allergen, the cartridges (10) being contained within an applicator (40) as claimed in any one of claims 7 to 25, wherein at least one said cartridge (10) at least partially protrudes from the applicator (40);

d] ejecting the said protruding cartridge (10) from the applicator (40).