Study
of the
Role
of Insects
in its Etiology
and
the
Use
of DDT
in its Treatment
By HARVEY BLANK, M.D., BERTRAM SHAFFER, M.D., MALCOLM C. SPENCER, M.D.,
AND WILLIAM C. MARSH, M.D.
Philadelphia
P
APULAR urticaria (lichen urticatus) has been a common and puzzling disease ofinfancy and childhood. Several important characteristics suggest the role of insects in its etiology. It appears during the warmer months, is more common in lower social and economic groups, and usually disappears upon admission to the hospital. In a
pre-liminary report,’ the authors indicated the importance of flea and bedbug bites in its
etiology in confirmation of Dietrich’s 3 and reported their success in therapy with
DDT (dichlorophenyl-trichlor-ethane) . The present paper is a summary of observations
over a three year period.
A child with papular urticaria presents a fairly typical clinical picture. Pruritic skin lesions first appear usually during spring or summer (Chart 1
)
and crops of new lesions continue to occur in spite of palliative therapy. A history of similar lesions the precedingyear is frequently obtained. Persistent discrete questioning of the parents commonly
re-veals exposure of the child to the common dog or cat flea (Ctenocephalides canis and Ct.
felis) or less often to the bedbug (Cimex lectularius) or the human flea (Pulex irritans).
This may occur through contact with dogs or cats, sand boxes, coal piles, cellar debris,
and such articles as infested upholstered furniture, bedding or heavy pile rugs.
The lesions are characteristically distributed mostly on the arms and legs, particularly
on the extensor or exposed surfaces, on the face and neck, and usually least on the trunk (Chart 2). The genital, perianal and axillary regions are almost invariably clear. New lesions are often seen as small (3 to 10 mm.) wheal-like papules which later are rubbed and excoriated. As a result of scratching, many small individual bloody crusts are noted
which surmount flattened firm persistent papules or lichens. Secondary infection
com-monly results in impetiginization and pyogenic ecthymatous ulcers.
Several other skin diseases are frequently confused with papular urticaria. Scabies may mimic it most closely and is differentiated on clinical grounds by the frequent pre-dilection of scabies for the genital, perianal and axillary regions and its rare appearance
on the face in children over 3 months of age (Chart 2). In addition, papular urticaria
rarely appears in more than one member of a family, in distinction to scabies. If the
From the Department of Dermatology and Syphilology, University of Pennsylvania, Philadelphia, Pa.
The following hospitals cooperated in this study: The Children’s Hospital of Philadelphia, Hos-pita! of the University of Pennsylvania, Mt. Sinai Hospital, Graduate Hospital of the University of Pennsylvania, and the Skin and Cancer Hospital of Philadelphia.
Presented at the Annual Meeting of the Society for Pediatric Research, Atlantic City, N.J., May 3, 1949.
(Received for publication May 31, 1949.)
SCA8IES PAPULAR URTICARIA
CHART II
30
25
20
U) IS
U) 0 C.)
L 10
.0
E
z5
TIME OF ONSET OF 89 CASES OF PAPULAR URTICARIA
Jan. Feb. Mar Ap May June July Aug. Sept. Oct. Nov.
CHART I
diagnosis is in doubt a therapeutic test with a modern scabeticide such as benzyl benzoate is a wise procedure. Because such a lotion also affords a protective film against insects,
the papular urticaria may improve for a few days but quickly reappears at the cessation
of the scabies treatment. Head lice (Pediculosis capitis) or body lice (Pediculosis
corporis) occasionally cause extensive lesions in children and their presence should be
ruled out. Pyogenic infections also enter into the differential diagnosis. If adequate
meas-ures to eradicate bacterial infections, such as vigorous debridement with soap and water
and a softening ointment with or without Systemic penicillin therapy, fails to cure a
pyogenic infection in the characteristic body areas, an underlying papular urticaria or
scabies should be strongly considered. Common urticaria may be differentiated by the fact
that its lesions are transient, usually leave no residual papules and are seldom excoriated
or impetiginized. The tiny papules or wheals that may be the manifestations of ordinary
TABLE I
RESULTS OF SKIN TESTS WITH INSECT ANTIGENS
. Diluent Flea 1:5,000 Flea 1:10,000 . Cimex 1:5,000 Flea and/or Cimex
Patients with papular urticaria
No, patients tested 30 12 17 30 30
No. patients positive 0 10 9 10 23
%
patients positive 0 83 53 33 77Control subjects
No. subjects tested 124 28 96 124 124
No. subjects positive 0 0 0 2 2
% subjects positive 0 0 0 2 2
urticaria in infants are distributed most commonly on the trunk, in distinction to the
‘‘centrifugal’ ‘ distribution of chronic papular urticaria, and do not result in chronic lichenified papules.
Although the exact mechanism whereby this disease affects one child in a family is not
certain, abnormal sensitivity to insects can often be demonstrated. Of 87 patients with papular urticaria, it was possible to elicit a history of known exposure to fleas in 26
cases and to bedbugs in eight cases. In addition, possible exposure, from the presence of
cats, dogs, sand boxes, etc., was indicated in 72 of the patients. Skin tests with flea and bedbug antigens were performed on 30 of these patients. The antigens were prepared
according to Cherney4 by extracting the dried pulverized insects with phenol 0.5% in
saline for 48 hours and passing through a “Swinney” type Seitz filter. The extract was prepared in a dilution of 1:5,000 and 1:10,000 for flea,* and 1:5,000 for bedbug,f calculated on the original dry weight of the insects used. The control solution was the phenol 0.5% in saline diluent. The skin tests were read in 48 hours. A positive reaction
consisted of a distinct elevated papule 3 mm. or more in diameter. Table I indicates that
* The flea antigen was prepared from cat fleas (Ctenocephalides felis) supplied by W. V. King, U. S. Dept. of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine, Orlando, Fla.
52 CASES
77% of the patients with papular urticaria were sensitive either to flea or cimex or to both. In a control series of 124 subjects, most of whom were children in corresponding
age groups, only two had positive skin tests. These studies will be reported in greater
detail elsewhere.
To insure unequivocal results from an evaluation of treatment with DDT, no other
medications of any type were used during the period of observation, and each patient was followed carefully at weekly intervals. The parents were given an instruction sheet with a supply of DDT 5% in talc to be used as a dusting powder on the patient and in his bedding. At the beginning of the study, a few patients were treated with DDT 5%
COMPARISON OF THE RESULTS OF TREATMENT OF PAPULAR URTICARIA
FORMER METHODS(CONTROL) DDT
88 CASES
25
20 20
cr1
I5 I5
I
ri
ci-#{149}#{149} 0 100 w::
IJ ...>::: d
%
::::0 :::- 0: CURED IMPROVED
:: H ::i:
AVERAGE TIME REQUIRED TO EFFECT THE RESULT INDICATED
CHART III
in a shake lotion, hut this was discarded to obviate the remote possibility that the lotion itself might have some beneficial effect. The instruction sheet read as follows:
PAPULAR URTICARIA
This is a disease of the skin. It is usually caused by sensitivity to insects. The common insects that cause it are fleas from dogs, cats, house, sand or other humans; as well as bedbugs and possibly other insects. It is necessary, therefore, for you to remove all sources of these insects.
INSTRUCTIONS
1. A .cpray of 5% DDT in Flit is to be used daily in your household. The baseboards, the cellar, the bed frames and upholstered furniture should receive special attention.
2. A powder of 5% DDT should be dusted on dogs and cats, under cushions and rugs, and
wherever the spray cannot be used.
3. Contact with dogs and cats should be avoided. 4. All collections of sand should be removed.
Note: Be certain to check the label of the sprays and powders you buy. Be sure that they contain
DDT and in at least 5% strength.
PRECAUTIONS
1. When spraying with DDT, make certain that food, dishes and cooking utensils are protected from the spray. Avoid direct contact with the spray and ventilate the room after the spraying.
2. To avoid eating of the DDT powder by cats: after dusting the fur, the excess powder should be removed with a damp cloth.
3. The powder should be dusted very lightly on the child as only the barest film is necessary.
The results of 54 patients treated with the DDT regime and 88 by a variety of other
methods are indicated in Chart 3. All patients were included for whom adequate follow-up examinations made it possible to record a definite result. There were
approxi-mately an equal number of boys and girls ; about 60% of the patients were Negroes.
Of the DDT group, 86% were considered cured, i.e., they had no new lesion and
experienced complete cessation of itching within two weeks. Although 2 1
%
of the con-trols were appraised as cured, it required an average of 1 1 weeks before this result couldbe recorded. The improved group included the patients in whom there was a reduction in pruritus but in whom there was continued appearance of new lesions, although these were fewer in number. In this category were 39% of the control group and 8% of the
DDT treated patients. A study of the records of the control group indicated that many
of these patients got well or improved spontaneously with the termination of the insect season.
The patients treated with DDT who failed to respond rapidly were followed carefully
in the clinic and by home visits. In this way, one apparent failure was cured by the
purchase of a new mattress when, for some unexplained reason, bedbugs were found in the depths of the mattress in Spite of DDT dusting. The three persistent failures were seen for an average of six months. These apparently represent the small group in whom
the disease is induced by agents other than the above insects. The persistence of lesions
in these patients during the winter months also suggests this. In the DDT failure group,
two patients responded by partial and temporary improvement to an elimination diet, while
in the remaining patients new lesions were induced by exposure to heat or by wearing excessive clothing. A complete disappearance of these lesions, however, was not obtained
by reducing these factors.
CONCLUSIONS
Papular urticaria (lichen urticatus) is a chronic disease which in the great majority
of cases occurs during the warm seasons on exposure to fleas and bedbugs.
Skin tests indicate many such patients are abnormally sensitive to these insects.
In the three year study reported, it was demonstrated that 86% of the patients could
be cured in two weeks with a 5% DDT dusting powder and DDT household spray,
whereas with former methods of therapy, only 21
%
were cured in 11 weeks oftreat-ment.
REFERENCES
1. Shaffer, B., Spencer, M. C., and Blank, H., Papular urticaria: Its response to treatment with DDT and role of insect bites in its etiology, J. Invest. Dermat. 11:293, 1948.
2. Dietrich, A., Hautreaktionen nach Ungezieferbissen, Monatschr. f. Kinderh. 75:70, 1938. 3. Dietrich, A., Hautreaktionen nach Ungezietersticken unter dem Bildeiner Lichen Urticatus, Arch.
f. Dermat. u. Syph. 182:668, 1942.
4. Mclvor, B. C., and Cherney, L. S., Studies in insect bite desensitization, Am. J. Trop. Med. 21:
SPANISH ABSTRACT
Urticaria Papular: Un Estudio del Papel que Insectos tienen en Su Etiologia
y el Uso de DDT en Su Tratamiento
La urticaria Papular (Lichen urlicatus) es una enfermedad cr#{243}nica en Ia mayor parte de casos ocurre durante las estaciones calientes a! exponerse a moscas y chinches.
Ensayos de Ia pie! indican que muchos de estos pacientes son anormalmente sensibles a estos insectos.
En un estudio de 3 afios se ha demostrado que 86% de los pacientes pueden ser curados en 2 semanas con un 5% de polvo DDT y rociados de casa DDT, mientras que con los m#{233}todos antiguos de terapia, solamente un 21% fueron curados en 11 semanas de tratamiento.
