pH Determinations of the Skin

H DETERMINATIONS OF THE SKIN READINGS UNDER NORMAL AND ABNORMAL CONDITIONS*

HENRY W. JOLLY, JR., M.D., CHENAULT W. HAlLEY, M.D. AND JOE NETICK, M.D.

With the development of the glass electrode for the measurement of hydrogen iron concentration in the 1930s, interest was renewed in studying the acid-base balance of skin surfaces. This method has proved to be much more accurate than the older colorimetric and clcctrometric methods. With its usc, Blank (1—2), Draizc (3), Anderson (4), Klaudcr and Gross (5), Wacck (6), and Bearc and associates (7) have reported findings on normal and diseased human skins and on animal skins. The present investigation began as a basic and elementary study of "hand cczcmas", with

more emphasis on etiology than treatment.

by a ground glass joint. Both electrodes were equipped with 30 inch leads, properly shielded to prevent leakage and to resist electrostatic pick-up.

The electrodes were checked and adjusted against a standard solution buffered to a known

pH of 7.0 between observations on different patients. The skin was prepared by a drop of unbuffered 0.1 per cent NaC1 solution, which had been adjusted to a pH of 5.0. The pH of this solution changed gradually throughout the experiment but remained within a range of 5.0 and 7.0. It has been shown that if the pH of this solution remains between 4.0 and 9.0, readings will vary less than

pH (1). This was confirmed by us. If firm "electrical" contact is made with the skin, without any conducting solution (this is impossible under very dry conditions), a reading is obtained which

One of the first factors we needed to determine in this study was the pH of the skin. It seemed varies slightly or not at all from readings made that there must be one or more basic underlying with the conduction solution. The skin was not factors that cause certain people to be repeatedly cleansed or prepared in any other way than the

troubled with hand eruptions whereas others method outlined above. Thus the values presented under apparently similar conditions never have in this paper represent, for all practical purposed, any difficulty. Conceivably, one of these factors the true pH of the skin surface for the sites tested. might involve pH variations. Because the investi-

The electrodes were placed at the sites approxi-

gation of the pH of the skin became interesting mately 1 cm. apart, were gently rotated until

and constituted a major project in itself, our good contact was established and were held there while the readings on the pH Meter were recorded. The sites used were the dorsa of the hands between

findings arc here being presented separately. METHOD OF DETERMINATIONS

For this study, methods comparable to those described by the aforementioned authors were

used, with new and more refined equipment available today. The Beckman laboratory pH

Meter, Model G, was used. This is an extremely accurate instrument,battery operated, and recommended for laboratory investigations. The electrode, Beckman M40485, is exceptionally rated, capable of withstanding shocks and high pressure, and recommended for measuring pH of flat, moist surfaces, including soil. The reference electrode is Beckman M39170 fiber-type calomel, filled with a saturated solution of potassium chloride, contact with the skin by this solution being accomplished *From the Department of Dermatology, Louisi-

ana State University School of Medicine and Charity Hospital of Louisiana, New Orleans.

This study was supported in part by a grant

from the Ethyl Corporation.

Received for publication June 4, 1960. 305

the third and fourth metacarpo-phalangeal joints, the approximate centers of the palms, an area at the junction of the neck and the back, the dorsa of the feet between the third and fourth metatarsophalangeal joints, and the plantar surface of the feet, where two areas were determined as will be indicated in the charts. SELECTION OF PATIENTS

Twenty-seven hundred and sixty-six determi-

nations were made on four general groups of patients: (1) Normal people, with no apparent skin disease; (2) "Hand Eczemas", limited to the chronic hand dermatitides of unknown etiology,

commonly called "house wives eczema", and excluding as much as possible those due to fungous infection, psoriasis, contact dermatitis and the like. Patients with active and dormant unclassified hand eczemas were included, for example, recalcitrant pustular eruptions, dyshi-

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306

TABLE 2

drotic eczema, infectious eczematoid dermatitis, and various other similar clinical classifications;

Patients with history of hand eczema

(3) miscellaneous dermatoses involving any portion of the body and with some apparent systemic connection; (4) Griseofulvin-treated patients. When our study overlapped the "Griscofulvin Era", we wondered what, if any effect this

drug, taken in recognized therapeutic doses and with the required amount of the drug in the epidermis, would have on the pH of the skin.

With the exception of group 4 in which all the patients were children, the study included all

tc

Site

Right palm Left palm Right hand

dorsum

Left hand dorstim

Right foot dorsum Left foot dorsum

Right plaotar Ball times of the year and patients of varied sex, Arch age and race. Previous studies have sufficiently Left plantar distinguished differences in sex, age, and race. Ball This study was designed to illustrate overall Arch differences in disease states, with particular Neck-upper hack

Average pu

102 102 102 102

5.748

100

5.467

100

5.431

14 78

6.832

14 79 98

6.656

5.741 5.567

5.522

5.425

5.499 5.430

reference to people prone to develop hand eruptions.

TABLE 3 Patients with active hand eczemas

RESULTS

Nine hundred aud forty-three determinations were made on people considered to have normal skin. These subjects included physicians, nurses,

medical students, friends of patients attending

Dermatology Clinic, and out-patients in the Neurological Clinic. The results tabulated in Table 1 arc self-explanatory. Readings on the plantar surfaces, in this and in the other categories as well, were taken in the two areas indicated because such variations were reported by Marchionini and Cerutti (8). Eight hundred and nirity-one determinations were done on patients who had chronic dermatitis

of the hands or were known to be recurrent TABLE 1 Persons with normal skin Site

Numher patients Site Average pH

Palms

Involved Uninvolved

6.146 5.599

TABLE 4 Patients with miscellaneous deriuatoses Site

Right palm Left palm Right hand dorsum Left hand dorsum Right foot dorsum Left foot dorsum

Average pH

17

Right plantar Ball

Arch

Average pH 95 95 95 95 94

5.739 5.745 5.613 5.676 5.790

94

5.771

18

6.717

73

5.603

18 73 95

6.659 5.595 5.534

Left plantar

Right palm Left palm Right hand dorsum Left hand dorsum Right foot dorsum Left foot dorsum Right plantar Ball

Arch

106 106 106 106 104 102 16

89

5.847 5.877 5.850 5.901 5.633 5.641 6.704 5.658

Left plantar

Ball

16

Arch

89

Neck-upper back

103

6.753 5.572 5.653

Ball Arch Neck-upper back

sufferers with such a complaint. Only patients were included in whom no specific etiology (fungus, definite contact, generalized psoriasis) was demonstrable. Wherever possible, uninvolved skin was used for readings in Table 2. In patients

in whom dual readings were made, one on involved and one on uninvolved skin, comparisons are indicated in Table 3. No attempt was.

H OF THE SKIN

made to "prepare" these or any other patients for readings. Very few of the patients in this group were "new". In our private offices and public clinics, we have seen few such patients who have not been treated previously, either

307

Table 5. Notable are the large number of cases of seborrheic dermatitis, the inclusion of which was desirable because the skin in this disease

has been reported to have a higher pH value than normal skin, by Anderson (4) and Beare

by another physician, a druggist, or by the and associates (7). patient himself with home remedies. It would Eighty-one determinations were made on therefore seem impossible to obtain patients nine children with tinea capitis before adminifor study who are uncontaminated by local stration of Griseofulvin was begun and again two medication. Because of their discomfort, few patients can forego treatment, even if they are willing to cooperate. With the exception of one person alone who used extremely acid prepara-

weeks later (Table 6). All the children were seen

in a charity clinic, but since the drug was furnished free to each patient, it is presumed that it was taken. The dosage in each case was 1 gram

tions, the variations in this group were no greater of Griseofulvin daily. There were no controls with than those in the other groups. whom to compare these patients. The only

Eight hundred and fifty-one determinations interest in them was whether deposition of the

were made on patients with miscellaneous chemical in the skin altered its pH. Interestingly dermatoses (Table 4). A definite attempt was the areas that are normally washed most fremade to include disease with systemic involve- quently exhibited the least change in pH. It has

ment and to exclude purely local problems, been pointed out at several conferences on such as warts. The various diseases and the Griseofulvin that repeated washing of the skin average respective pH for each are included in could leech out the drug and perhaps reduce its TABLE 5 Classification by miscellaneous dermatoses Disease

N Pts.

Palm

L

R.

L.

R.

L

Hand Hand Foot Foot Palm Dorsum Dorsum Dorsum Dorsum

R. Plantar

—

Ball

Arch

L. Plantar Neck

Ball

Arch

Seborrhea etc

16

5.940 5.868 5.885 6.012 5.097 5.811 6.940 5.582 6.600 5.613 5.543

Lupus erythematosus. .

13 11

6.119 6.100 5.965 6.157 5.965 5.983 6.775 5.677 6.937 5.911 5.487 5.423 5.273 5.353 5.625 5.622 6.900 5.509 6.750 5.251 5.803 5.775 5.595 5.525 5.771 5.637 7.000 5.578 7.100 5.427 5.387 5.456 5.303 5.288 5.767 5.812 6.600 5.725 7.100 5.576

Acne Contact Tinea Psoriasis

Atopic Porphyria Carcinoma of skin Yeast infection

8 8 4 4 3 3 2

5.875 5.662 5.662 5.802 5.467 5.627 5.483 5.400 5.400 5.966 5.216 5.600 4.875 5.215 4.590 5.000 5.750 5.350 4.775 5.225 5.900 5.825 5.466 5.733

5.775 7.300 6.083 7.100 6.000 5.502 5.320 5.450 5.450 6.000 5.940 6.100 5.525 5.600 5.900 5.900 5.050 6.500 5.400 6.000 5.000 6.375 5.900 5.750 5.800 5.850 5.530 5.433 5.400 5.000

Herpes simplex

2 2

Infection

2

6.075 5.950 5.900 5.900 5.450 5.750 5.375 5.260 5.785 5.705 6.175 5.995 6.800

tis, hands Acute lichen planus....

1

6.200 6.700 6.700 6.500 5.600 5.400

1

Pityriasis rosea

1

6.600 6.600 6.400 6.700 5.100 5.200 5.200 5.300 4.650 4.750 5.500 4.750

Allergic vasculitis

1

Stasis eczema

1

6.000 5.850 6.400 5.800 5.600 5.700 5.500 5.500 6.030 5.940 5.370 5.500

Pemphigus

1

5.500 6.100

Parapsoriasis (acute). .

1

Herpes zoster

1

Erythema nodosum....

Nummular eczema.....

5.569 5.526 5.487 5.260 5.662

5.645 5.766 5.033 4.975 5.125

5.175 5.650 6.250 6.100 5.890 6.195 5.750

Chronic radiodermati-

6.500 5.400 4.900 6.600 5.140

5.800 5.000 6.300 5.200

5.800 4.600 6.000 4.500

7.000

5.800 5.100 6.300

1

6.720 5.500 5.400 5.700 5.500 5.750 5.750 6.720 6.340 5.700 5.700 5.200 5.200 4.900 6.000 6.300 6.400 5.300 5.130 5.460 5.550 7.230 6.920

6.140 5.950

1

6.300 6.150 6.600 6.100 6.000 6.000

6.800 6.000

1

5.548

6.400

6.100 6.600 7.200 6.870

Infectious eczematoid dermatitis (ears)

Miscellaneous

&708 5.275 5.358 5.868 6.020

6.250

5.418

5.360 5.570

308

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Tir,ea

TABLE 6

differ significantly from the normals and actually

capitis patients

had lower values for the sites observed. This indicates these patients are capable of maintaining an acid skin if sufficient time elapses

Num-

ber

Site

Patients

Right palm...... Left palm Right hand dorsum Left hand dorsum Right foot dorsum Left foot dorsum Right plantar arch Left plantar arch Neck-upper back

10 10

10 10 10 10 10 10 10

Average pH

Post-

PreGriseo-

Griseo-

fulvin

after exposure to soap, water and other alkalis.

5.860 5.810 6.180 6.210 5.800 5.820 5.600 5.890 5.570

5.910 5.900 6.340 6.130 6.070 6.170 6.410 6.380 5.570

broken down and presented as a matter of record.

5.860

6.100

fulvin

The table on miscellaneous dermatoses is

TABLE 7

Normal subject, before and after washings

The difference in pH between the arch and ball of the foot noted by others, is confirmed by

us, and is presumably due to difference in evaporation between the two areas. The differ-

ences between the actively weeping areas of dermatitis compared to the chronic areas is confirmed by us and presumably due to the alkalinity of the serum. Increase in pH after washing with ordinary toilet cake soap is confirmed.

The increase in pH while taking Griseofulvin is interesting, but the variation and the number of patients observed is small.

Before Washings

After Washings

SUMMARY

6.250 6.400

Statistical data are presented on two thousand, seven hundred and sixty-six pH determinations made on three hundred and twelve persons in

Left hand dorsum Right foot dorsum

5.600 5.850 5.400 5.600 5.000

Right plantar

5.700

site

Right palm Left palm

Right hand dorsum

6.800 7.500 4.600 4.650

four groups: (1) patients with no disease, (2) patients with "unclassified" hand dermatitis, (3) patients with miscellaneous dermatoses, and

(4) patients with tinea capitis before and after treatment with Griseofulvin. This study was therapeutic effect. One wonders if the increase in undertaken as the first step in an investigation the overall average pH of skin, supposedly into basic factors in the pathogenesis of hand produced by administration of Griseofulvin eczemas. The interesting results prompted us to could account for the increased tendency of moniliasis as a complication of Griseofulvin present them as a separate report. REFERENCES 1. BLANK, I. H.: Measurement of pH of the skin surface. J. Invest. Derm., 2:67, 1939. subjects wash her hands a total of ten times with the use of ordinary cake toilet soap. Only 2. BLANK, I. H.: pH of the exposed surfaces of therapy. For added interest, we had one of our "normal"

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The pH values for our "normals" are some-

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