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Oral PABA and vitiligo
Journal of the American Academy of Dermatology
Correspondence
770
Fig. 1. Scanning electron micrograph of latex condom surface showing raised, superficial irregularities but no pores, fissures, or other defects. ( x 30,000.)
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Fig. 2. Transmission electron micrograph of latex condom cross-section showing irregular, dense inclusions; there are no defects which might compromise the integrity of the membrane. (x40,O00.) sion electron microscopy 800 to 1,000 .~ thick crosssections were prepared at - 8 0 " C and then viewed at magnifications as high as • 200,000. Scanning electron microscopy of the condom surface was performed directly on both stretched and unstretched specimens at
magnifications as high as • Stretch forces applied to the condom were chosen qualitatively to approximate stresses encountered in actual use. Visible on both cross-section and surface views were numerous raised, superficial irregularities in the latex; however, review of many fields showed a complete absence of pores or other detects which might compromise the integrity of the condom (Figs. 1 and 2). Thus, this latex "prophylactic" presents a continuous membrane and represents an effective physical barrier to direct transmission of the herpesvirus. However, our conclusion only represents an in vitro study; the true effectiveness of the condom against herpes will be proportional to the care with which it is used in interpersonal situations. In addition, the results of our study cannot be extrapolated to include all condoms; indeed, the effectiveness of natural membrane condoms may be quite different. Furthermore, these findings may not be applicable to other latex condoms or products, e.g., latex examination gloves. Our study raises as many questions as it answers and highlights the need for further investigation.
L. Stephen Kish, M.D. James T. McMahon, Ph.D. Witma F. Bergfetd, M.D. John M. Pelachyk, M.D. Cleveland Clinic Foundation Department of Dermatology 9500 Euclid Ave. Cleveland, OH 44106 O r a l P A B A a n d vitiligo
To the Editor: I recently examined a 40-year-old Caucasian woman who developed scattered areas of vitiligo in sunexposed areas a few weeks after taking oral PABA (para-aminobenzoic acid) (1,000/day for 10 days). In addition, the patient's 13-year-old daughter took three tablets and a few weeks later developed a typical halo nevus that progressed to total depigmentation. These findings suggest that oral PABA may in some way inhibit melanin production, produce depigmentation of melanocytes, or perhaps act as a "systemic sunscreen." Oral PABA is advocated by some tanning facilities and health food stores to promote tanning. I wonder if other readers have seen this possible relationship between oral PABA and vitiligo. Charles G. Hughes, D.O. 2141 Academy Circle #104 Colorado Springs, CO 80909
Correspondence
770
Fig. 1. Scanning electron micrograph of latex condom surface showing raised, superficial irregularities but no pores, fissures, or other defects. ( x 30,000.)
,J
g:}
~,.
- ,~
,f'
Fig. 2. Transmission electron micrograph of latex condom cross-section showing irregular, dense inclusions; there are no defects which might compromise the integrity of the membrane. (x40,O00.) sion electron microscopy 800 to 1,000 .~ thick crosssections were prepared at - 8 0 " C and then viewed at magnifications as high as • 200,000. Scanning electron microscopy of the condom surface was performed directly on both stretched and unstretched specimens at
magnifications as high as • Stretch forces applied to the condom were chosen qualitatively to approximate stresses encountered in actual use. Visible on both cross-section and surface views were numerous raised, superficial irregularities in the latex; however, review of many fields showed a complete absence of pores or other detects which might compromise the integrity of the condom (Figs. 1 and 2). Thus, this latex "prophylactic" presents a continuous membrane and represents an effective physical barrier to direct transmission of the herpesvirus. However, our conclusion only represents an in vitro study; the true effectiveness of the condom against herpes will be proportional to the care with which it is used in interpersonal situations. In addition, the results of our study cannot be extrapolated to include all condoms; indeed, the effectiveness of natural membrane condoms may be quite different. Furthermore, these findings may not be applicable to other latex condoms or products, e.g., latex examination gloves. Our study raises as many questions as it answers and highlights the need for further investigation.
L. Stephen Kish, M.D. James T. McMahon, Ph.D. Witma F. Bergfetd, M.D. John M. Pelachyk, M.D. Cleveland Clinic Foundation Department of Dermatology 9500 Euclid Ave. Cleveland, OH 44106 O r a l P A B A a n d vitiligo
To the Editor: I recently examined a 40-year-old Caucasian woman who developed scattered areas of vitiligo in sunexposed areas a few weeks after taking oral PABA (para-aminobenzoic acid) (1,000/day for 10 days). In addition, the patient's 13-year-old daughter took three tablets and a few weeks later developed a typical halo nevus that progressed to total depigmentation. These findings suggest that oral PABA may in some way inhibit melanin production, produce depigmentation of melanocytes, or perhaps act as a "systemic sunscreen." Oral PABA is advocated by some tanning facilities and health food stores to promote tanning. I wonder if other readers have seen this possible relationship between oral PABA and vitiligo. Charles G. Hughes, D.O. 2141 Academy Circle #104 Colorado Springs, CO 80909