eMedicine Specialties > Emergency Medicine > Dermatology

Pityriasis Alba

Author: Rashid M Rashid, MD, PhD, Post-Graduate Year 2 and House Staff Resident, Department of Dermatology, MD Anderson Cancer Center, University of Texas and The Morzak Center
Coauthor(s): Andrew C Miller, MD, Chief Resident and Clinical Assistant Instructor, Departments of Emergency Medicine and Internal Medicine, State University of New York Downstate Medical Center, Kings County Hospital Center; Mark A Silverberg, MD, FACEP, MMB, Assistant Professor, Assistant Residency Director, Department of Emergency Medicine, State University of New York Downstate College of Medicine; Consulting Staff, Department of Emergency Medicine, Staten Island University Hospital, Kings County Hospital, University Hospital, State University of New York Downstate at Brooklyn
Contributor Information and Disclosures

Updated: Jun 11, 2009

Introduction

Background

Pityriasis alba is a term derived from the words scaly (pityriasis) and white (alba).


Note the characteristic, ill-defined, hypopigment...

Note the characteristic, ill-defined, hypopigmented macules in this 6-year-old child with pityriasis alba.

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Note the characteristic, ill-defined, hypopigment...

Note the characteristic, ill-defined, hypopigmented macules in this 6-year-old child with pityriasis alba.

Pathophysiology

No known cause of pityriasis alba has been reported. Atopy and postinflammatory changes are leading current theories as to the origin of the lesions. Theories of origin include hypopigmentation secondary to pityriacitrin, a substance produced by Malassezia yeasts, that acts as a natural sunscreen.

A large number of patients with pityriasis alba have a history of atopic disease. In addition, atopic patients are more prone to developing pityriasis alba.1

Histology of biopsy studies show features including hyperkeratosis (33.33%), parakeratosis (40%), acanthosis (53.33%), spongiosis (80%), and perivascular infiltrate (100%).1  However, these findings are not specific enough to make the diagnosis.

Atrophic sebaceous glands were noted in almost half the cases in one study.2

Anemia has been reported in up to 16% of patients.1 This may be a coincidental finding, and the clinical relevance of anemia is not yet known. 

Ultrastructure studies note that despite a reduced pigment in lesional skin, there is no difference in melanocytes between lesional and nonlesional skin in the same patient, although this finding is still under debate. Degenerative changes in melanocytes and reduced keratonocyte melanosomes were also noted.2 Overall, the defect is believed to be due to decreased melanin.

Frequency

United States

Pityriasis alba is relatively common, occurring in up to 5% of children, but the exact epidemiology has not been described.

Mortality/Morbidity

Pityriasis alba is often an incidental finding on clinical examination and generally a self-limited asymptomatic disease that may resolve without intervention. Mortality is not associated with this condition. Cosmetic appearance may be of concern in extensive disease.

Race

Pityriasis alba does not seem to be more prevalent in any race; however, it is more obvious in dark-skinned individuals.

Sex

No sex predilection has been noted. A slight male predominance has been noted.1

Age

Pityriasis alba is most often noted in those younger than 20 years.

Clinical

History

  • Pityriasis alba lesions often occur on the face. In particular, the cheek is a common site.1
  • Lesions may be erythematous or pruritic in the beginning, evolving into scaly, hypopigmented macules. Patients may complain that lesions are more prominent in the summer, secondary to the surrounding hyperpigmentations associated with prolonged sun exposure.

Physical

  • A flaky, hypopigmented, patchy dermatitis with fine scales involving the face and, at times, the neck and shoulders typically is found.


Lesions of pityriasis alba are usually bilateral ...

Lesions of pityriasis alba are usually bilateral and located on the face, arms, and neck.

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Lesions of pityriasis alba are usually bilateral ...

Lesions of pityriasis alba are usually bilateral and located on the face, arms, and neck.

  • Numerous (up to 20 or more) hypopigmented macules, which are ill defined and range in size from 1-4 cm, can be found.
  • The lesions of pityriasis alba tend to have less well-defined borders than lesions seen in vitiligo, and they do not coalesce as seen in tinea versicolor.
  • An association with atopy is believed to exist; therefore, some patients may have atopic dermatitis as well.

Causes

  • No definitive etiologic agent has been described.

More on Pityriasis Alba

Overview: Pityriasis Alba
Differential Diagnoses & Workup: Pityriasis Alba
Treatment & Medication: Pityriasis Alba
Follow-up: Pityriasis Alba
Multimedia: Pityriasis Alba
References
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References

  1. Vinod S, Singh G, Dash K, Grover S. Clinico epidemiological study of pityriasis alba. Indian J Dermatol Venereol Leprol. Nov-Dec 2002;68(6):338-40. [Medline].

  2. In SI, Yi SW, Kang HY, Lee ES, Sohn S, Kim YC. Clinical and histopathological characteristics of pityriasis alba. Clin Exp Dermatol. Jul 2009;34(5):591-7. [Medline].

  3. Fujita WH, McCormick CL, Parneix-Spake A. An exploratory study to evaluate the efficacy of pimecrolimus cream 1% for the treatment of pityriasis alba. Int J Dermatol. Jul 2007;46(7):700-5. [Medline].

  4. Lin RL, Janniger CK. Pityriasis alba. Cutis. Jul 2005;76(1):21-4. [Medline].

  5. Ortonne JP, Passeron T. Melanin pigmentary disorders: treatment update. Dermatol Clin. Apr 2005;23(2):209-26. [Medline].

  6. Rakel RE, Bope ET. Conn's Current Therapy 2005. 57th ed. St Louis: WB Saunders; 2005:999.

  7. Sams WM. Principles and Practice of Dermatology. New York: Churchill; 1990:369.

  8. Vargas-Ocampo F. Pityriasis alba: a histologic study. Int J Dermatol. Dec 1993;32(12):870-3. [Medline].

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Further Reading

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Keywords

pityriasis alba, extensive pityriasis alba, hypopigmentation, hypopigmented dermatitis, scaly skin, white skin, atopic dermatitis, atopy, atopic disease, tinea versicolor 

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Contributor Information and Disclosures

Author

Rashid M Rashid, MD, PhD, Post-Graduate Year 2 and House Staff Resident, Department of Dermatology, MD Anderson Cancer Center, University of Texas and The Morzak Center
Rashid M Rashid, MD, PhD is a member of the following medical societies: American Academy of Dermatology, Council for Nail Disorders, Houston Dermatological Society, and Texas Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

Andrew C Miller, MD, Chief Resident and Clinical Assistant Instructor, Departments of Emergency Medicine and Internal Medicine, State University of New York Downstate Medical Center, Kings County Hospital Center
Andrew C Miller, MD is a member of the following medical societies: American College of Emergency Physicians, American College of Physicians, American Medical Association, Emergency Medicine Residents Association, Islamic Medical Association of North America, Medical Society of the State of New York, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Mark A Silverberg, MD, FACEP, MMB, Assistant Professor, Assistant Residency Director, Department of Emergency Medicine, State University of New York Downstate College of Medicine; Consulting Staff, Department of Emergency Medicine, Staten Island University Hospital, Kings County Hospital, University Hospital, State University of New York Downstate at Brooklyn
Mark A Silverberg, MD, FACEP, MMB is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, Council of Emergency Medicine Residency Directors, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

David A Peak, MD, Assistant Residency Director of Harvard Affiliated Emergency Medicine Residency, Attending Physician, Massachusetts General Hospital; Consulting Staff, Department of Hyperbaric Medicine, Massachusetts Eye and Ear Infirmary
David A Peak, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, Society for Academic Emergency Medicine, and Undersea and Hyperbaric Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Mark W Fourre, MD, Program Director, Department of Emergency Medicine, Maine Medical Center; Associate Clinical Professor, Department of Surgery, University of Vermont School of Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Pamela L Dyne, MD, Professor of Clinical Medicine/Emergency Medicine, David Geffen School of Medicine at UCLA; Attending Physician, Department of Emergency Medicine, Olive View-UCLA Medical Center
Pamela L Dyne, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

 
 
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