Key points

• Six randomised, controlled trials have been reported, although methodological difficulties and small sample sizes limit the interpretation of the results.

• Future, large-scale pragmatic trials are needed if this issue is to be resolved.

• In the meantime, the use of allergen-impermeable mattress and pillow covers, coupled with regular vacuuming of the room seem to be the best way of reducing house dust mite if such changes are truly beneficial.

Will an exclusion diet (such as a milk- or eggfree diet) help to reduce the symptoms of this child's atopic eczema?

Will interventions to reduce house dust mite improve this child's eczema?

Study

Intervention

Population and sample size

Design and period of follow up

Main outcome measures

Main results

Quality of reporting

Comment

Colloff et al.

Daily natamycln

20 young adults

Parallel-group,

House dust mite

Vacuum cleaning (not

Method of

This trial was too small to

19891 (UK)

(spray to kill house

with atopic eczema

double-blind,

load; disease

natamycln spray) had

randomisation and

provide generallsable

dust mites) i/

and a positive RAST

factorial RCT;

severity (six

a significant Impact on

concealment not

results. Nevertheless, the

placebo spray, with

for house dust

follow up: 4 months

features at 16

reducing house dust

reported; no ITT

effectiveness of vacuuming

and without vacuum

mite IgE.

sites - not a

mite numbers.

analysis; very small

compared with sprays may

cleaning of the

Active spray +

validated scale)

Reduction In house

sample size

be useful In informing future

mattress (I.e. four

vacuuming (n = 6),

dust mite was not

study design

treatment groups)

active spray, no

associated with

vacuuming (n = 4),

Improvements in

placebo spray +

clinical severity

vacuuming (n = 5),

placebo spray, no

vacuuming (n = 5)

Tan et al.

Active Intervention:

30 adults and 30

Parallel-group,

House dust mite

Although the weight of

Method of

This was a small but

19961 (UK)

Goretex bedcovers,

children (aged >7

double-blind,

load; house dust

dust removed was

randomisation and

Important study.

benzyltannate spray

years) with atopic

placebo-controlled

mite allergen Der

significantly lower for

concealment not

Blinding may not have been

and daily high-

dermatitis;

trial; follow up:

p1\ disease

the active versus the

reported; no ITT

successful, given the very

filtration vacuuming.

48 completed the

6 months.

severity (SASSAD)

placebo group, the

analysis; small

different vacuum cleaners

Placebo intervention:

study - active group

level of the major dust

sample size

used.

cotton covers, water

(n = 28), placebo

allergen Der p1 In

This study suggests that

and ethanol spray

group (n = 20)

bedroom carpets was

vacuuming with an ordinary

and dally vacuum

dramatically reduced In

household cleaner achieves

cleaning with a

both groups.

similar reductions in house

normal machine

Disease severity reduced

dust mite antigen levels In

by a small amount In

bedroom carpets to those

both groups, but more

achieved by the

Study Intervention Population and Design and Main outcome Main results Quality of Comment sample size period of measures reporting

follow up

so in the active group

more expensive high-

(12-6 1/4-2 units).

filtration vacuum cleaners

Subgroup analysis

suggested that only

children had a

statistically significant

Improvement and that

there was no correlation

between clinical

Improvement and

positive skin prick tests

at study outset

Endo et al.

Intensive vacuum

30 children with Parallel-group, Physician-assessed

A statistically significant

Method of

Patients were probably not

19972

cleaning of carpets,

atopic eczema randomised controlled severity; house

decrease In mite

randomisation and

blinded adequately,

(Japan)

mattresses and

trial; follow up: 1 year dust mite load

numbers In favour of the

concealment not

although clinical scores

quilts by researchers

intensive cleaning group

reported; no ITT

were assessed by a

every 3 weeks v the

was only noted for the

analysis; clinical

physician blind to

same cleaning with

room floors. Clinical

scores were given In

treatment allocation.

the vacuum cleaner

scores were significantly

graphical form only

Comparison with normal

on 50% power

Improved In the active

and the appropriate

vacuuming would have

group compared with

statistical test of

been helpful

baseline but not In the

mean difference

control group

between the two

treatments was not

reported

Study

Intervention

Population and

Design and

Main outcome

Main results

Quality of

Comment

sample size

period of

measures

reporting

follow up

Ricci et al.

Active Intervention:

41 children aged > 2

Two-part study.

Disease severity

Severity scores In the

Randomisation

This study had an unusual

20006

encasing mattresses

years with atopic

Part 1: single-blind

(SCORAD). House

active group Improved

method not clear

design and It is not entirely

(Italy)

and pillows, hot

dermatitis

randomised

dust mite load;

from 33 to 26 (21%) at

and probably

clear why they abandoned

weekly wash of

controlled trial of

house dust mite

2 months. In the control

Inappropriate; no

the initial randomised

bedding, living room

2 months duration.

allergens Dep p1

group, scores reduced

ITT analysis; the

groupings after 2 months.

and bedroom

Part 2: all patients

and Der f1

from 27 to 24 (11%).

appropriate statistical

The active Intervention was

vacuumed twice a

allocated to active

Dust mite load and

test of mean

very Intensive and

week, soft toys

Intervention and

allergens were reduced

difference between

probably not appropriate

washed weekly and

followed up from

In both groups.

the two groups was

for wide-scale

removed from the

2 months to 1 year

Follow up study: after

not reported

Implementation

bedroom.

12 months, both groups

Control Intervention:

showed Improvements In

normal cleaning

clinical severity and dust

load, but there was no

longer a control group

Gutgesell

Active Intervention:

20 adults with

Double-blind,

Disease severity

A significant reduction In

Randomisation

This Is again a very small

et al. 20015

allergen-

moderate to severe

placebo-controlled

(SCORAD); dust

dust mite allergen was

method was not clear,

study. Nevertheless,

(Germany)

Impermeable

atopic dermatitis

randomised

mite allergen (Der

found, but this did not

but otherwise the

Gutgesell et al. should be

mattress cover,

with sensltisatlon to

controlled trial.

pi): topical steroid

translate into significant

methods were

commended for the

plus acariclde spray

the house dust mite

Follow up: 1 year

usage; patient-

Improvements In clinical

reasonably robust.

Inclusion of patient-

(tannic acid and

assessed pruritus

severity, topical steroid

The most limiting

specific outcome

benzylbenzoate).

and pruritus-

use or patient-assessed

factor of the study

measures In this study, as

Placebo Intervention:

Induced sleep loss

pruritus.

was Its small sample

the clinical relevance of

cotton bed covers,

size, although all 20

small Improvements on

plus water and

patients did complete

disease severity scales is

ethanol spray)

the study

often difficult to assess

Table 17.4 (Continued)

Study

Intervention

Population and sample size

Design and period of follow up

Main outcome measures

Main results

Quality of reporting

Comment

Holm et al.

Active Intervention:

43 adults with atopic

Follow up: 1 year.

Disease severity

Disease severity was

Randomisation method

This was a small and

20014

mattress and pillow

dermatitis. Exclusion

Double-blind,

(SCORAD); house

reduced In both groups

and concealment were

relatively inconclusive

(Sweden)

covers, duvets

criteria Included the

placebo-

dust mite load; total

(45% in the active group,

unclear; no ITT

study. The active

washed monthly at

use of potent topical

controlled trial.

IgE and IgE to house

39% In the control group).

analysis was

Intervention was very

>60°, carpets and

steroids

Follow up: 1 year

dust mite In blood

Compared with baseline,

performed and the

Intensive

mattress vacuumed

serum; weekly diary

house dust mite exposure

appropriate statistical

weekly.

of Itch intensity (not

was significantly reduced

test of mean difference

Placebo Intervention:

mentioned In results)

In the active group, as

between the two

cotton covers only

was house dust mite specific IgE. Patients not sensitised to house dust mite allergens benefited from the bedcovers as much as sensitised patients

groups was not reported

ITT, intentlon-to-treat; SASSAD Six Area Six Sign Atopic Dermatitis, SCORAD, severity scoring of atopic dermatitis

ITT, intentlon-to-treat; SASSAD Six Area Six Sign Atopic Dermatitis, SCORAD, severity scoring of atopic dermatitis

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