Abstract
(Part I ).
#1. The test of susceptibility to scarlet fever first
introduced by the Dicks has been described. Its
relationship to the Schultz- Charlton -phenomenon
and to the etiology of scarlet fever has been
considered.
#2. The divergent results obtained by other workers
have been briefly presented.
#3. 160 cases of scarlet fever have been skin tested
at weekly intervals. The methods adopted and the
results obtained have been described and summarised.
#4. The anomalies of the test as noted in these cases
and as described by other workers have been
reviewed.
#5. An attemtt has been made to assess the relative
importance of these anomalies.
#6. The conception of scarlet fever as an allergic
phenomenon has been considered.
From a survey of this work it seems
possible to form the following conclusions: -
1. That in general the Dick test forms a
reliable index of susceptibility to scarlet fever is
in my opinion unquestionable.
2. The paradoxical behaviour of the test
has been to some extent exaggerated. It is possible
that some of the anomalous features described may be
due to the development of an allergic state.
3. Scarlet fever is due to infection with a
haemolytic streptococcus. It is not a disease entity,
but is a clinical syndrome, of which an eruption of
particular character and distribution forms an
essential feature. The continued use of such an
expression as "Scarlatina sine Eruptione" can only
lead to confusion. In any consideration of the value
of the Dick test some such definition as the above
must be accepted by all workers, if comparable results
are to be obtained.
4. If scarlet fever is to follow such an
infection, three conditions are necessary: -
(1) The infecting streptococcus must be highly
toxigenic.
(2) The host must have an insufficient general
immunity.
(3) The skin of the infected person must be
susceptible to the toxin.
General and local resistance are not necessarily
parallel.
5. The fact that in certain persons and at
certain periods of life they do not run parallel does
not form a sufficient reason for the discarding of
the view that scarlet fever is caused by a specific
toxin.
6. The conception of scarlet fever as an
allergic phenomenon is based on a series of
inconclusive animal experiments, a fallacious assumption that general and local resistance must coincide,
and a too destructive criticism of the Dick test.
7. The conception of scarlet fever as a
specific toxaemia is more convincing. From the
available evidence it is at present the only one
acceptable.
* * * * * * * * * * * * * * * *
(Part II.)
1. A condition of hypersensitiveness to products of
the haemolytic streptococcus has been described by
various writers. It has been possible to
demonstrate the development of this allergic state
during the course of scarlet fever.
2. The preparation has been described of an extract
representing the soluble intracellular Products of
the organism freed from diffusible substances.
3. Using this material the skin reactions in 74 cases
of scarlet fever have been studied. In the first
week of the illness all the reactions were negative
or feebly developed, but in the fourth week 66
patients (almost 90 %) gave positive reactions.
4. 28 of these cases were tested at weekly intervals;
in these cases the positive reaction was sometimes
present in the second, and usually present in the
third week.
5. Age is an imoortant factor in the development of
this skin sensitivity. All the cases over 7 years
of age developed the allergic reaction. The older
age groups tended to become positive at an earlier
stage than the younger children and their
sensitivity became greater as judged by the
intensity of the skin reactions.
6. Normal persons are frequently sensitive to this
type of preparation, but young children are
rarely so. The reactions noted after scarlet
fever cannot be regarded, therefore, as a
recrudescence of a pre- existing skin sensitiveness.
7. Repeated skin testing in control cases produces
no such increase in reaction.
8. Although in many cases skin sensitivity to H.S.E.
and Dick toxin is inversely related, this
relationship is not a constant one.
9. The possible significance of this allergic state
in the causation of scarlatinal nephritis and
scarlatinal arthritis needs further study.
10. A case of scarlatinal arthritis with a particul:
:arly intense skin reaction has been described.
This would appear to sharply differentiate
scarlatinal arthritis from acute rheumatism.
11. The persistence of this allergic condition may be
of importance in the development of the
"rheumatic state ". This possibility has been
discussed. 3 cases tested a year later have
retained their sensitivity to H.S.E. i of
these cases has developed chorea.
12. 160 persons not suffering from scarlet fever have
also been skin tested with H.S.L. Age has an
important influence on the results. The reaction
appears to be inhibited in chronic cardiac
disease and wasting conditions,but to a less
extent in acute infections unless these be of
exceptional severity.
13. The results in erysipelas contrast sharply with
those in scarlet fever. In erysipelas the skin
teaction is positive on admission to hospital and
appears to remain so at all stages of the disease.
In the absence of extreme illness a negative
reaction in an adult patient should question the
diagnosis of erysipelas. In young patients the
skin reaction in this disease is still unknown.
14. A proportion of cases of puerperal infection show
an increasing sensitivity as in scarlet fever.
The possibility of this being a recrudescence of
a pre- existing skin sensitiveness is difficult to
exclude unless the reaction to H.S.E. be tested
before infection. The relationship between the
skin changes and the infecting organism needs
further study.
15. At the present stage the work is in so many
respects incomplete that conclusions must be
necessarily limited. It will only be possible
to assess the importance of the results already
obtained by following up each new line of
investigation as it suggests itself, while tr;ing
not to lose our perspective of the problem as a
whole.
16. It is doubtful if we can hope to make much real
progress until the mechanism of these skin
reactions is better understood, and their
significance in relation to the vital processes
in general better appreciated.
