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Measurement of pH of the Skin Surface
MEASUREMENT OF pH OF THE SKIN SURFACE IV. DAILY VARIATIONS FOR ADULT FEMALES WITH No APPARENT SKIN LESIONS IRVIN H. BLANK, PH.D.' (Received for publication May 8, 1939)
It was predicted in previous papers of this series that adult females with no apparent skin lesions might show appreciable
day to day variations in the pH of the skin surface. If such variations do exist, it then becomes important to make numerous determinations on single individuals before comparing one with
the other. Five adult females, ages 20 to 25 with no apparent skin lesions, were chosen and pH determinations on six areas of each arm were
made as nearly daily as possible over a six months period. The time did not run consecutively in all cases, but in general extended from late summer to early spring. Each individual was measured
approximately 120 times. The technique for making the measurements was described in the first paper (1) of this series. In measuring these five individuals it was found that some were
more constant than others. In figure 1, there are shown the variations which occurred in the pH readings on the extensor surface of the upper arm for the two individuals who showed the maximum and the minimum daily changes. Note that in one the range is from 4.58 to 6.85 with a maximum change within a 24-hour interval of nearly two units. In the second individual, the range is from 5.00 to 6.12 with a maximum 24-hour change of only about 0.5 units. This investigation was aided by a grant for research from the National Oil Products Company, Harrison, New Jersey.
Read before the Second Annual Meeting of the Society for Investigative
Dermatology, St. Louis, May 16, 1939. 1 From the Department of Dermatology and Syphilology, Harvard Medical
School and Massachusetts General Hospital; C. Guy Lane, M.D., Chief. 235
236
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
It seems unnecessary to present in detail the variations for all areas of the five individuals during the six months that they were studied. For the purpose of a more complete analysis of the differences which may occur in normal skins, we have shown in tables 1 and 2 the distribution of all of the readings made on the one of our group who had the highest readings and the one who had the lowest readings. In one case, the individual was measured 120 times; in the other, 117 times. Table 3 6
itip T
I I I I I I I SI1oWIN THE DAILY VAP.%PTQNUP.tNG OctosR \93 IN THE — -— R IF TIlE
I I I I
I
I
I
oc THE E%TENSOR $UP.ACE MR.
6$ I 6.
6.
a'
Ia.
I
\j iiY' 1 2345 C 7 88 iOu laI3I4,6i6J7I8Io2oalZ324as227eoao3I D1-E
shows the means and the standard deviations for these areas. Since the means in both of these cases are greater than the means reported for the average of female adults (2), it can be assumed
that neither of these individuals represents a minimum among adult females and hence differences from individual to individual even larger than these must exist. From the standard deviations, it can be seen that the pH readings for different areas on an individual with normal skin may be predicted to show a daily variation of at least 0.7 to 1.0 pH units above and below the mean. To what may such large variations
237
MEASUREMENT OF pH OF SKIN SURFACE TABLE 1 Showing the distribution of 1O daily pH measurements for "Miss A"
?. . ,. o Forearm (flexor surface)..
pH o
.',
.30
.3,
.3
'0
'0
'0
3 10 26 24 20 16
3
2 .3
.3o
.3,
'0
7 7 3
1
Forearm (extensor surface) Antecubital Elbow
2 1
3
1 5 14 14 20 23 16 11 3 18 27 23 26 15 2 1 1 5 10 17 26 22 15 12 5
2 5 3
3
1
4 2
1
10
6 2
1
2
14 18 22 17 19 11
6 7
1
2
Upper arm (flexor surface) Upper arm (extensor surface)
8 3
17 19 29 20
7
TABLE 2 Showing the distribution of 117 daily pH measurements for "Miss B" PH 4.00 4.20 4.4&4.60 4.80 5.00 5.20 5.40 5.60 5.80 6.00
to
to to
to
to
to
4.19 4.39 4.59 4.79 4.99 5.19
Forearm (flexor surface) Forearm (extensor surface) Antecubital Elbow Upper arm (flexor surface) Upper arm (extensor surface)
1 1
6 8 11 12 5 5 8 9
4 9 15 23 21 16 2 7 4 8 12 1 2 8 8 12 2 4 5 6
to to
to
to
24 11
2
37 21
2
to
5.39 5.59 5.79 5.99 6.20
16 10 20 12 19 15
26 19 7 37 35 18
2 26 24
8 7 28 32
1 1 7
TABLE 3 Summary of pH measurements for "Miss A" and "Miss B" ME.N
ST.'.NDARD D5VIATION
'Miss A" 'Miss B"
"Miss A" "Miss B"
Forearm (flexor surface) Forearm (extensor surface) Antecubital
5.78 6.04
Elbow
6.02 5.92 6.10
Upper arm (flexor surface) Upper arm (extensor surface)
5.48
5.35
0.415
0.411
5.51
0.457
0.413
4.85 5.36 5.37 5.58
0.343
0.484
0.376 0.397
0.440 0.444
0.356 0.369
238
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
be attributed? It seems unlikely that errors in technique of measuring are responsible, because the individuals were not uniformly high or uniformly low on the same day (see fig. 1) and because almost each time any one was measured, the increased
alkalinity of the extensor surfaces, as compared to the flexor surfaces, was apparent. We have attempted to roughly correlate the pH with the menstrual cycle and with the environmental temperature. In I
I
- - - SHOWING iHE AVERAGE AIL' pH os
--es
I
- —
E]
THE SYsW3 SURFACE OF
—
--
u
'S
60.
::
----
--
---
--
5.
7
---
-
a 3 4 5 788 0.! I 13 14 IS 16 7 (8 IaZoalZaa3Z4 ZS 2.6 Vi DAYs FOILOWING ONSET OF MENSTRUATION
two of the five individuals, there appears to be some repetition
from cycle to cycle in the curves of the average pH values. But the curves of these two individuals differ appreciably from one another. One shows a general tendency to rise from the onset of menstruation to approximately one week previous to the onset of the next menses, at which time there is a fairly sharp decline. The second shows a spiking curve during the first two weeks following the onset of menstruation which flattens out at the low level for the third week and rises again during the fourth week. These curves are shown in figures 2 and 3, in which the
239
MEASUREMENT OF pH OF SKIN SURFACE
value for any one day is the arithmetic average of ten readings made on the two arms. The other three individuals showed no repetition from cycle to cycle. Only two of our individuals were measured during very warm weather. The averages of measurements made in September and October showed no consistent differences from the averages of readings made on the same individuals during January and February. There did appear to be a drop in the pH, that is, the
iIl: :
=I
I
I
-
--
-
Eicua
:r
—----—----
- - .SHOWINS THE AVEP,ASE OMLY 0 THE SHIN 3UAE OF THE AP.MS 7j
-
-
-
6.!
—
---
-
6
—--
I6 = ft : - j 4
-,
I ui I=u i?t.L/ / =
IL_\_ 1 \
,r
5
—
\
o ,:
.i h
L'
It
/
T- •J — - -
-
DAYS Fouo'.j,Me ONSET OF MENOThUATION
skin became more acid, when there was a sudden rise in temperature; and there was a subsequent return toward the alkaline side
when the temperature again dropped. There is not yet enough data available to state definitely that the pH of the skin surface can be correlated to either the menstrual cycle or the environmental temperature. There appear to be other factors playing a role. These factors may at times mask the effect of temperature and menstruation on the pH of the skin surface. Because of the wide variations which exist for normal skins
240
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
from individual to individual and within the same individual from day to day, it becomes at once apparent that until a large number of individuals with any one type of dermatitis have been measured, no definite statement should be made relative to the variation of the pH of the surface of the pathologic skin
from the normal. At the present time it would seem more advisable to try to learn the cause of the daily variations in normal skins than to determine the actual variation between normal and pathologic skins. In other words, what factors control the pH of the surface of the skin? SUMMARY
Wide variations in the daily pH measurements on the skin surfaces of five adult females with no apparent skin lesions have
been shown to exist. For each of two of these individuals, a curve showing the daily variations appears to repeat itself from one menstrual cycle to the next; this was not apparent for the other three. No correlation between the pH of the skin surface and the environmental temperature could be definitely established, although there was some indication that the pH dropped as the temperature increased. Since these wide variations exist, several measurements should be made on the skin of any one individual before stating that that individual differs from the normal. BIBLIOGRAPHY (1) BLANK, I. H.: Measurement of pH of the skin surface, I. Technique. J. Invest. Dermatol., 2: 67—74, 1939.
(2) BLANK, I. H.: Measurement of pH of the skin surface. II. pH of the exposed surfaces of adults with no apparent skin lesions. J. Invest. Dermatol., 2: 75—79, 1939.
DISCUSSION DR. TKEODORE CORNBLRET, Chicago: Dr. Blank chose the really ideal instru-
ment for his purpose. It works rapidly and accurately; it is not cumbersome in use, such as are the quinhydrone and antimony electrodes. Substances which ordinarily interfere with accuracy when some of the other electrodes are used do not do so with the glass electrode. The most important of these substances are those constituting oxidation-reduction systems. Tissues and tissue fluids and secretions contain them. In determining pH values of biological materials electrically, the glass electrode, therefore, is the indicated instrument.
DISCUSSION
241
These studies like previous ones show that the normal reaction of the surface of the skin is acid. Recently, attempts have been made to show that this surface acid is of definite use. The most prominent one to be mentioned is the role as bacteriostatic or fungistatic agent. One function not mentioned and probably of some importance is the use of the acid reaction in maintaining an environment near the isoelectric point of keratin. At this point keratin, as is the case with any other protein, is most inert. It is obvious that such an accomplishment could be
useful. DR. CARL W. LAYMON, Minneapolis: Dr. Blank is to be commended on his ex-
cellent work. Marchionini and his coworkers (Arch. 1. Dermat. u. Syph., 176: 613, 1938), recently conducted experiments dealing with the pH of the skin of seborrheic individuals which indicated that the "seborrheic areas" of the body are more alkaline than other parts of the skin surface. Furthermore the alkaline areas were shown to be less bactericidal than the rest of the skin thus predisposing
to cutaneous infection. Studies such as these of Dr. Blank may thus prove to have great practical value in certain dermatoses. DR. C. Guy LANB, Boston: I have been very much interested in watching the work of Dr. Blank, and especially in the care he has taken in the establishment of
standards. This care is indicated in the charts which he has made. The consistency of his readings has been quite striking and his work gives us fundamental studies which will be quite useful in further investigations later on. The consistent minor difference shown between the flexor and extensor surfaces
should be emphasized. As Dr. Laymon has pointed out, it may assume significance in diagnosis and perhaps be of some aid in the treatment of disease as time progresses. In addition this study demonstrates very well the opportunities for cooperation between medicine and commercial firms in the carrying on of basic studies coincident with the progress of other research in a particular field. DR. IRVIN H. BLANK, Boston: I believe that each of the men has made some
important addition to the paper. Primarily, they have been concerned with what is causing or is respdnsible for the maintenance of the pH of the skin surface,
or for variations from area to area. We have been quite conscious of these problems, but I do not believe that the work done so far gives us the solutions to them. With respect to keratin acting as a buffer, which Dr. Peck seems to think is incorrect, I am sure that I would agree with him. I doubt if the liquid film on the surface of the skin can possess a sufficiently high concentration of keratin to act as a
buffer, Sweat surely has a great deal to do with it. Marchionini has written several articles in the last year corresponding for the most part to the data which Dr. Peck says he also has found. I did not wish to go into the theory of the glass electrode. I am glad that Dr. Cornbleet added that. I can state that, not only is the glass electrode free from the errors he mentioned, but it is also free from protein and salt errors, and free for the most part from electrode poisonings, all of which are encountered in the measurements of pH with other types of electrodes. I have no comment in reference to the discussions of the other men.
242
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
DR. SA,rnRL M. PECK, New York: I was very much interested in Dr. Blank's paper because of the investigations we have been conducting on sweat for the past two years. The H ion concentration can be considered under normal conditions as an expression of the acid contents of sweat. I believe that the pH of the skin surface is mainly due to the fluids which bathe it, i.e. for the most part the excretion of the sweat glands. Many investigators say that keratin acts as a buffering agent, thus eliminating to a great extent the effect of sweat on the p11. I really do not believe this from my experiments. Sweat from the arms is mainly acid, but if allowed to stand for any length of time it becomes alkaline due to bacterial action. This is brought about by the formation of sodium, potassium or ammonium salts of the fatty acids which dissociate but little. It is very interesting from the biologic viewpoint to evaluate the pH of the skin surface in terms of the contents of the sweat. These variations depend upon definite chemical substances found in the sweat.2 There is a different output of fatty acids under various endocrine, digestive and even emotional influences. The age of the patient is important because at puberty the action of many of the skin glands assume new functions. This is of special significance when we consider the pH of the axilla and pubic region at that period of life. I think these experiments are very much worthwhile because they give us in-
sight into part of the chemical biological mechanism which plays a role in preventing bacterial invasion. 2 Role of sweat as a fungicide, by Samuel M. Peck, M.D., Herbert Rosenfeld, M.D., William Leifer, M.D., and Walter Bierman, M.D., Arch. of Derm. and Syphil., January, 1939; 39: pp. 126—146.
The effects of hydrogen ion concentration, fatty acids and vitamin C on the growth of fungi, by Samuel M. Peck and Herbert Rosenfeld, Journ Invest. Derm., 1: no. 4, August, 1938.
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
94
linolenic acid extract. Arch. This pdf is a scanned copy UV of irradiated a printed document.
24. Wynn, C. H. and Iqbal, M.: Isolation of rat
skin lysosomes and a comparison with liver Path., 80: 91, 1965. and spleen lysosomes. Biochem. J., 98: lOP, 37. Nicolaides, N.: Lipids, membranes, and the 1966.
human epidermis, p. 511, The Epidermis
Eds., Montagna, W. and Lobitz, W. C. Acascopic localization of acid phosphatase in demic Press, New York. human epidermis. J. Invest. Derm., 46: 431, 38. Wills, E. D. and Wilkinson, A. E.: Release of 1966. enzymes from lysosomes by irradiation and 26. Rowden, C.: Ultrastructural studies of kerathe relation of lipid peroxide formation to tinized epithelia of the mouse. I. Combined enzyme release. Biochem. J., 99: 657, 1966. electron microscope and cytochemical study 39. Lane, N. I. and Novikoff, A. B.: Effects of of lysosomes in mouse epidermis and esoarginine deprivation, ultraviolet radiation and X-radiation on cultured KB cells. J. phageal epithelium. J. Invest. Derm., 49: 181, 25. Olson, R. L. and Nordquist, R. E.: Ultramicro-
No warranty is given about the accuracy of the copy.
Users should refer to the original published dermal cells. Nature, 216: 1031, 1967. version of1965. the material. vest. Derm., 45: 448, 28. Hall, J. H., Smith, J. G., Jr. and Burnett, S. 41. Daniels, F., Jr. and Johnson, B. E.: In prepa1967.
Cell Biol., 27: 603, 1965.
27. Prose, P. H., Sedlis, E. and Bigelow, M.: The 40. Fukuyama, K., Epstein, W. L. and Epstein, demonstration of lysosomes in the diseased J. H.: Effect of ultraviolet light on RNA skin of infants with infantile eczema. J. Inand protein synthesis in differentiated epi-
C.: The lysosome in contact dermatitis: A ration. histochemical study. J. Invest. Derm., 49: 42. Ito, M.: Histochemical investigations of Unna's oxygen and reduction areas by means of 590, 1967. 29. Pearse, A. C. E.: p. 882, Histochemistry Theoultraviolet irradiation, Studies on Melanin, retical and Applied, 2nd ed., Churchill, London, 1960.
30. Pearse, A. C. E.: p. 910, Histacheini.stry Thearetscal and Applied, 2nd ed., Churchill, London, 1960.
31. Daniels, F., Jr., Brophy, D. and Lobitz, W. C.: Histochemical responses of human skin fol-
lowing ultraviolet irradiation. J. Invest. Derm.,37: 351, 1961.
32. Bitensky, L.: The demonstration of lysosomes by the controlled temperature freezing section method. Quart. J. Micr. Sci., 103: 205, 1952.
33. Diengdoh, J. V.: The demonstration of lysosomes in mouse skin. Quart. J. Micr. Sci., 105: 73, 1964.
34. Jarret, A., Spearman, R. I. C. and Hardy, J. A.:
Tohoku, J. Exp. Med., 65: Supplement V, 10, 1957.
43. Bitcnsky, L.: Lysosomes in normal and pathological cells, pp. 362—375, Lysasames Eds., de Reuck, A. V. S. and Cameron, M. Churchill, London, 1953.
44. Janoff, A. and Zweifach, B. W.: Production of inflammatory changes in the microcirculation by cationic proteins extracted from lysosomes. J. Exp. Med., 120: 747, 1964.
45. Herion, J. C., Spitznagel, J. K., Walker, R. I. and Zeya, H. I.: Pyrogenicity of granulocyte lysosomes. Amer. J. Physiol., 211: 693, 1966.
46. Baden, H. P. and Pearlman, C.: The effect of ultraviolet light on protein and nucleic acid synthesis in the epidermis. J. Invest. Derm.,
Histochemistry of keratinization. Brit. J. 43: 71, 1964. Derm., 71: 277, 1959. 35. De Duve, C. and Wattiaux, R.: Functions of 47. Bullough, W. S. and Laurence, E. B.: Mitotic control by internal secretion: the role of lysosomes. Ann. Rev. Physiol., 28: 435, 1966. the chalone-adrenalin complex. Exp. Cell. 36. Waravdekar, V. S., Saclaw, L. D., Jones, W. A. and Kuhns, J. C.: Skin changes induced by
Res., 33: 176, 1964.
It was predicted in previous papers of this series that adult females with no apparent skin lesions might show appreciable
day to day variations in the pH of the skin surface. If such variations do exist, it then becomes important to make numerous determinations on single individuals before comparing one with
the other. Five adult females, ages 20 to 25 with no apparent skin lesions, were chosen and pH determinations on six areas of each arm were
made as nearly daily as possible over a six months period. The time did not run consecutively in all cases, but in general extended from late summer to early spring. Each individual was measured
approximately 120 times. The technique for making the measurements was described in the first paper (1) of this series. In measuring these five individuals it was found that some were
more constant than others. In figure 1, there are shown the variations which occurred in the pH readings on the extensor surface of the upper arm for the two individuals who showed the maximum and the minimum daily changes. Note that in one the range is from 4.58 to 6.85 with a maximum change within a 24-hour interval of nearly two units. In the second individual, the range is from 5.00 to 6.12 with a maximum 24-hour change of only about 0.5 units. This investigation was aided by a grant for research from the National Oil Products Company, Harrison, New Jersey.
Read before the Second Annual Meeting of the Society for Investigative
Dermatology, St. Louis, May 16, 1939. 1 From the Department of Dermatology and Syphilology, Harvard Medical
School and Massachusetts General Hospital; C. Guy Lane, M.D., Chief. 235
236
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
It seems unnecessary to present in detail the variations for all areas of the five individuals during the six months that they were studied. For the purpose of a more complete analysis of the differences which may occur in normal skins, we have shown in tables 1 and 2 the distribution of all of the readings made on the one of our group who had the highest readings and the one who had the lowest readings. In one case, the individual was measured 120 times; in the other, 117 times. Table 3 6
itip T
I I I I I I I SI1oWIN THE DAILY VAP.%PTQNUP.tNG OctosR \93 IN THE — -— R IF TIlE
I I I I
I
I
I
oc THE E%TENSOR $UP.ACE MR.
6$ I 6.
6.
a'
Ia.
I
\j iiY' 1 2345 C 7 88 iOu laI3I4,6i6J7I8Io2oalZ324as227eoao3I D1-E
shows the means and the standard deviations for these areas. Since the means in both of these cases are greater than the means reported for the average of female adults (2), it can be assumed
that neither of these individuals represents a minimum among adult females and hence differences from individual to individual even larger than these must exist. From the standard deviations, it can be seen that the pH readings for different areas on an individual with normal skin may be predicted to show a daily variation of at least 0.7 to 1.0 pH units above and below the mean. To what may such large variations
237
MEASUREMENT OF pH OF SKIN SURFACE TABLE 1 Showing the distribution of 1O daily pH measurements for "Miss A"
?. . ,. o Forearm (flexor surface)..
pH o
.',
.30
.3,
.3
'0
'0
'0
3 10 26 24 20 16
3
2 .3
.3o
.3,
'0
7 7 3
1
Forearm (extensor surface) Antecubital Elbow
2 1
3
1 5 14 14 20 23 16 11 3 18 27 23 26 15 2 1 1 5 10 17 26 22 15 12 5
2 5 3
3
1
4 2
1
10
6 2
1
2
14 18 22 17 19 11
6 7
1
2
Upper arm (flexor surface) Upper arm (extensor surface)
8 3
17 19 29 20
7
TABLE 2 Showing the distribution of 117 daily pH measurements for "Miss B" PH 4.00 4.20 4.4&4.60 4.80 5.00 5.20 5.40 5.60 5.80 6.00
to
to to
to
to
to
4.19 4.39 4.59 4.79 4.99 5.19
Forearm (flexor surface) Forearm (extensor surface) Antecubital Elbow Upper arm (flexor surface) Upper arm (extensor surface)
1 1
6 8 11 12 5 5 8 9
4 9 15 23 21 16 2 7 4 8 12 1 2 8 8 12 2 4 5 6
to to
to
to
24 11
2
37 21
2
to
5.39 5.59 5.79 5.99 6.20
16 10 20 12 19 15
26 19 7 37 35 18
2 26 24
8 7 28 32
1 1 7
TABLE 3 Summary of pH measurements for "Miss A" and "Miss B" ME.N
ST.'.NDARD D5VIATION
'Miss A" 'Miss B"
"Miss A" "Miss B"
Forearm (flexor surface) Forearm (extensor surface) Antecubital
5.78 6.04
Elbow
6.02 5.92 6.10
Upper arm (flexor surface) Upper arm (extensor surface)
5.48
5.35
0.415
0.411
5.51
0.457
0.413
4.85 5.36 5.37 5.58
0.343
0.484
0.376 0.397
0.440 0.444
0.356 0.369
238
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
be attributed? It seems unlikely that errors in technique of measuring are responsible, because the individuals were not uniformly high or uniformly low on the same day (see fig. 1) and because almost each time any one was measured, the increased
alkalinity of the extensor surfaces, as compared to the flexor surfaces, was apparent. We have attempted to roughly correlate the pH with the menstrual cycle and with the environmental temperature. In I
I
- - - SHOWING iHE AVERAGE AIL' pH os
--es
I
- —
E]
THE SYsW3 SURFACE OF
—
--
u
'S
60.
::
----
--
---
--
5.
7
---
-
a 3 4 5 788 0.! I 13 14 IS 16 7 (8 IaZoalZaa3Z4 ZS 2.6 Vi DAYs FOILOWING ONSET OF MENSTRUATION
two of the five individuals, there appears to be some repetition
from cycle to cycle in the curves of the average pH values. But the curves of these two individuals differ appreciably from one another. One shows a general tendency to rise from the onset of menstruation to approximately one week previous to the onset of the next menses, at which time there is a fairly sharp decline. The second shows a spiking curve during the first two weeks following the onset of menstruation which flattens out at the low level for the third week and rises again during the fourth week. These curves are shown in figures 2 and 3, in which the
239
MEASUREMENT OF pH OF SKIN SURFACE
value for any one day is the arithmetic average of ten readings made on the two arms. The other three individuals showed no repetition from cycle to cycle. Only two of our individuals were measured during very warm weather. The averages of measurements made in September and October showed no consistent differences from the averages of readings made on the same individuals during January and February. There did appear to be a drop in the pH, that is, the
iIl: :
=I
I
I
-
--
-
Eicua
:r
—----—----
- - .SHOWINS THE AVEP,ASE OMLY 0 THE SHIN 3UAE OF THE AP.MS 7j
-
-
-
6.!
—
---
-
6
—--
I6 = ft : - j 4
-,
I ui I=u i?t.L/ / =
IL_\_ 1 \
,r
5
—
\
o ,:
.i h
L'
It
/
T- •J — - -
-
DAYS Fouo'.j,Me ONSET OF MENOThUATION
skin became more acid, when there was a sudden rise in temperature; and there was a subsequent return toward the alkaline side
when the temperature again dropped. There is not yet enough data available to state definitely that the pH of the skin surface can be correlated to either the menstrual cycle or the environmental temperature. There appear to be other factors playing a role. These factors may at times mask the effect of temperature and menstruation on the pH of the skin surface. Because of the wide variations which exist for normal skins
240
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
from individual to individual and within the same individual from day to day, it becomes at once apparent that until a large number of individuals with any one type of dermatitis have been measured, no definite statement should be made relative to the variation of the pH of the surface of the pathologic skin
from the normal. At the present time it would seem more advisable to try to learn the cause of the daily variations in normal skins than to determine the actual variation between normal and pathologic skins. In other words, what factors control the pH of the surface of the skin? SUMMARY
Wide variations in the daily pH measurements on the skin surfaces of five adult females with no apparent skin lesions have
been shown to exist. For each of two of these individuals, a curve showing the daily variations appears to repeat itself from one menstrual cycle to the next; this was not apparent for the other three. No correlation between the pH of the skin surface and the environmental temperature could be definitely established, although there was some indication that the pH dropped as the temperature increased. Since these wide variations exist, several measurements should be made on the skin of any one individual before stating that that individual differs from the normal. BIBLIOGRAPHY (1) BLANK, I. H.: Measurement of pH of the skin surface, I. Technique. J. Invest. Dermatol., 2: 67—74, 1939.
(2) BLANK, I. H.: Measurement of pH of the skin surface. II. pH of the exposed surfaces of adults with no apparent skin lesions. J. Invest. Dermatol., 2: 75—79, 1939.
DISCUSSION DR. TKEODORE CORNBLRET, Chicago: Dr. Blank chose the really ideal instru-
ment for his purpose. It works rapidly and accurately; it is not cumbersome in use, such as are the quinhydrone and antimony electrodes. Substances which ordinarily interfere with accuracy when some of the other electrodes are used do not do so with the glass electrode. The most important of these substances are those constituting oxidation-reduction systems. Tissues and tissue fluids and secretions contain them. In determining pH values of biological materials electrically, the glass electrode, therefore, is the indicated instrument.
DISCUSSION
241
These studies like previous ones show that the normal reaction of the surface of the skin is acid. Recently, attempts have been made to show that this surface acid is of definite use. The most prominent one to be mentioned is the role as bacteriostatic or fungistatic agent. One function not mentioned and probably of some importance is the use of the acid reaction in maintaining an environment near the isoelectric point of keratin. At this point keratin, as is the case with any other protein, is most inert. It is obvious that such an accomplishment could be
useful. DR. CARL W. LAYMON, Minneapolis: Dr. Blank is to be commended on his ex-
cellent work. Marchionini and his coworkers (Arch. 1. Dermat. u. Syph., 176: 613, 1938), recently conducted experiments dealing with the pH of the skin of seborrheic individuals which indicated that the "seborrheic areas" of the body are more alkaline than other parts of the skin surface. Furthermore the alkaline areas were shown to be less bactericidal than the rest of the skin thus predisposing
to cutaneous infection. Studies such as these of Dr. Blank may thus prove to have great practical value in certain dermatoses. DR. C. Guy LANB, Boston: I have been very much interested in watching the work of Dr. Blank, and especially in the care he has taken in the establishment of
standards. This care is indicated in the charts which he has made. The consistency of his readings has been quite striking and his work gives us fundamental studies which will be quite useful in further investigations later on. The consistent minor difference shown between the flexor and extensor surfaces
should be emphasized. As Dr. Laymon has pointed out, it may assume significance in diagnosis and perhaps be of some aid in the treatment of disease as time progresses. In addition this study demonstrates very well the opportunities for cooperation between medicine and commercial firms in the carrying on of basic studies coincident with the progress of other research in a particular field. DR. IRVIN H. BLANK, Boston: I believe that each of the men has made some
important addition to the paper. Primarily, they have been concerned with what is causing or is respdnsible for the maintenance of the pH of the skin surface,
or for variations from area to area. We have been quite conscious of these problems, but I do not believe that the work done so far gives us the solutions to them. With respect to keratin acting as a buffer, which Dr. Peck seems to think is incorrect, I am sure that I would agree with him. I doubt if the liquid film on the surface of the skin can possess a sufficiently high concentration of keratin to act as a
buffer, Sweat surely has a great deal to do with it. Marchionini has written several articles in the last year corresponding for the most part to the data which Dr. Peck says he also has found. I did not wish to go into the theory of the glass electrode. I am glad that Dr. Cornbleet added that. I can state that, not only is the glass electrode free from the errors he mentioned, but it is also free from protein and salt errors, and free for the most part from electrode poisonings, all of which are encountered in the measurements of pH with other types of electrodes. I have no comment in reference to the discussions of the other men.
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DR. SA,rnRL M. PECK, New York: I was very much interested in Dr. Blank's paper because of the investigations we have been conducting on sweat for the past two years. The H ion concentration can be considered under normal conditions as an expression of the acid contents of sweat. I believe that the pH of the skin surface is mainly due to the fluids which bathe it, i.e. for the most part the excretion of the sweat glands. Many investigators say that keratin acts as a buffering agent, thus eliminating to a great extent the effect of sweat on the p11. I really do not believe this from my experiments. Sweat from the arms is mainly acid, but if allowed to stand for any length of time it becomes alkaline due to bacterial action. This is brought about by the formation of sodium, potassium or ammonium salts of the fatty acids which dissociate but little. It is very interesting from the biologic viewpoint to evaluate the pH of the skin surface in terms of the contents of the sweat. These variations depend upon definite chemical substances found in the sweat.2 There is a different output of fatty acids under various endocrine, digestive and even emotional influences. The age of the patient is important because at puberty the action of many of the skin glands assume new functions. This is of special significance when we consider the pH of the axilla and pubic region at that period of life. I think these experiments are very much worthwhile because they give us in-
sight into part of the chemical biological mechanism which plays a role in preventing bacterial invasion. 2 Role of sweat as a fungicide, by Samuel M. Peck, M.D., Herbert Rosenfeld, M.D., William Leifer, M.D., and Walter Bierman, M.D., Arch. of Derm. and Syphil., January, 1939; 39: pp. 126—146.
The effects of hydrogen ion concentration, fatty acids and vitamin C on the growth of fungi, by Samuel M. Peck and Herbert Rosenfeld, Journ Invest. Derm., 1: no. 4, August, 1938.
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linolenic acid extract. Arch. This pdf is a scanned copy UV of irradiated a printed document.
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