AUTHOR INFORMATION

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Authored by Dara A Kass, MD, Clinical Assistant Instructor, Department of Emergency Medicine, State University of New York Downstate Medical Center, Kings County Hospital

Coauthored by Richard Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center; Reza Keshavarz, MD, MPH, Clinical Assistant Professor, Departments of Pediatrics and Emergency Medicine, Mount Sinai School of Medicine; Director of Pediatric Emergency Medicine, Mount Sinai Hospital

Dara A Kass, MD, is a member of the following medical societies: American College of Emergency Physicians, Emergency Medicine Residents' Association, and Society for Academic Emergency Medicine

Edited by David A Peak, MD, Instructor, Staff Physician, Department of Emergency Services, Massachusetts General Hospital, Harvard Medical School; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; 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; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; and Pamela Dyne, MD, Program Director, Associate Professor, Department of Medicine, Division of Emergency Medicine, University of California at Los Angeles School of Medicine

Author's Email:	Dara A Kass, MD
Editor's Email:	David A Peak, MD

eMedicine Journal, May 22 2006, VOLUME 7, Number 5

INTRODUCTION

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Background: Pityriasis alba is a common hypopigmented dermatitis that occurs primarily in preadolescent children. It is often an incidental finding made on clinical examination. This is a self-limited disorder that usually resolves by adulthood.

Frequency:

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

Mortality/Morbidity: It is generally self-limited and asymptomatic disease. There is no mortality. Cosmetic appearance may be an issue 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.

Age: Pityriasis alba is most common in children aged 3-16 years. It occasionally may occur in adults.

CLINICAL

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History:

• Lesions often occur on the face of school-aged children.

• They 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.

• There can be numerous (up to 20 or more) hypopigmented macules, which are ill defined and range in size from 1-4 cm.

• 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.

• Hypopigmentation may occur in other disorders, such as those caused by fungi (eg, tinea versicolor), previous inflammatory conditions (eg, postinflammatory hypopigmentation), idiopathic disorders (eg, vitiligo), or malignancy (mycosis fungoides), or it may occur secondary to medications such as retinoic acid, benzoyl peroxide, and topical steroids. Clinicians should rule out these other disorders when evaluating a patient who may have pityriasis alba.

DIFFERENTIALS

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Dermatitis, Atopic
Dermatitis, Contact
Psoriasis
Tinea

Other Problems to be Considered:

Mycosis fungoides

WORKUP

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Lab Studies:

• A workup may be undertaken to exclude other causes of hypopigmentation.

• Potassium hydroxide stain of a skin scraping will be positive if the patient has tinea versicolor.

• Wood light examination will help in a patient who has vitiligo.

Procedures:

• A biopsy of the lesions usually is not necessary and not indicated in the emergency department. Pathologic findings are nonspecific; however, findings may include a basal layer with irregular pigmentation, follicular plugging, edema between epithelial cells (ie, spongiosis), or atopy of the sebaceous glands.

TREATMENT

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Emergency Department Care: No specific management is indicated or necessary in the ED.

Consultations:

• Consultation with a dermatologist usually is unnecessary. The patient's primary care provider typically provides follow-up care.

• Extensive pityriasis alba may warrant a referral to a dermatologist for possible pulsed ultraviolet A (PUVA) therapy.

MEDICATION

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Since the disease usually is self-limited and asymptomatic, medical therapy is often unnecessary. Pityriasis alba has no medical consequences, and the side effects of the medications may outweigh the cosmetic benefit of intervention. The most commonly used remedies (eg, emollients, topical steroids, PUVA) appear to have limited efficacy.

Emollients are used to reduce the scaling of the lesions, especially on the face.

Topical steroids may help with erythema and pruritus during the initial lesions and may accelerate repigmentation of existing lesions.

Psoralen plus ultraviolet light A photochemotherapy (PUVA) may be used to help with repigmentation in extensive cases, although the recurrence rate is high after treatment is stopped.

Drug Category: Corticosteroids, topical -- These agents have anti-inflammatory properties and cause profound and varied metabolic effects. They modify the body’s immune response to diverse stimuli.

Drug Name	Hydrocortisone (Cortaid, Cortizone-10) -- An adrenocorticosteroid derivative suitable for application to skin or external mucous membranes. Has mineralocorticoid and glucocorticoid effects, resulting in anti-inflammatory activity.
Adult Dose	Apply sparingly to affected areas bid/qid
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; not for use as monotherapy in primary bacterial infections (eg, cellulitis, angular cheilitis, impetigo, erysipelas, and paronychia); not for use in rosacea, perioral dermatitis, or acne; not for use on face, groin, or axilla
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Prolonged use, applying over large surface areas, application of potent steroids, and occlusive dressings may increase systemic absorption of corticosteroids and may cause Cushing syndrome, reversible HPA axis suppression, hyperglycemia, and glycosuria

FOLLOW-UP

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Further Outpatient Care:

• Outpatient follow-up generally is provided by a primary care provider.

• Extensive or recalcitrant cases may need the care of a dermatologist.

Prognosis:

• Depigmentation is not permanent.

• Pityriasis alba generally is self-limited, and the lesions typically resolve by adulthood.

• The duration of symptoms is different for each patient. Parents should be aware lesions may persist for many months.

• Treatment may shorten the duration of the lesions to several weeks in certain cases.

Patient Education:

• Education should focus on the lack of permanency of the dermatitis.

• Prolonged steroid therapy, especially on the face, is not necessary and may lead to toxicity.

• The lesions usually fade as the child grows older.

MISCELLANEOUS

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Medical/Legal Pitfalls:

• Failure to address other causes of hypopigmentation such as vitiligo or tinea versicolor.

• Failure to diagnose mycosis fungoides in a patient with persistent lesions.

TEST QUESTIONS

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CME Question 1: A 9-year-old boy presents to the ED with an asthma exacerbation. He has approximately 10 patches of hypopigmentation with fine, white flaking skin. The patches are asymptomatic and localized to the face. Which of the following statements is true?

A: A potassium hydroxide preparation will allow the physician to make the diagnosis.
B: These lesions are associated with seizures in some patients.
C: The described condition is most likely to be apparent during periods of minimal sun exposure.
D: The described condition typically is associated with arthritis.
E: The described condition generally is self-limited and resolves without any therapy.

The correct answer is E: The diagnosis of pityriasis alba is made on clinical grounds, and the lesions generally resolve spontaneously.

CME Question 2: Which of the following statements regarding pityriasis alba is true?

A: It typically requires a biopsy for diagnosis.
B: It usually is treated with oral steroids.
C: It is more common in patients with atopy and asthma than in patients without these conditions.
D: It commonly presents during adolescence and adulthood.
E: It often leads to scarring despite appropriate therapy.

The correct answer is C: Pityriasis alba is more common in patients with atopy and asthma than in those unaffected by these conditions. A subgroup of patients have associated atopy, in which stigmata of that disorder may be found.

Pearl Question 1 (T/F): Tinea versicolor is a cause of hypopigmentation in childhood.

The correct answer is True: Other causes of hypopigmentation in childhood include postinflammatory hypopigmentation, vitiligo, and medications (eg, retinoic acid, benzoyl peroxide, topical steroids).

Pearl Question 2 (T/F): Hypopigmentation of pityriasis alba generally resolves by adulthood.

The correct answer is True: Pityriasis alba is most common in children aged 3-16 years. In one study, 90% of cases were in children younger than 12 years. It occasionally may occur in adults.

Pearl Question 3 (T/F): The inner ear is the most common location for pityriasis alba.

The correct answer is False: Pityriasis alba is most commonly found on the face.

Pearl Question 4 (T/F): Pityriasis alba is most common in college-aged adults.

The correct answer is False: Pityriasis alba is most common in school-aged children.

BIBLIOGRAPHY

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• Habif T: Clinical Dermatology : A Color Guide to Diagnosis and Therapy. 4th ed. St Louis: Mosby; 2004: 119, 689.
• Hurwitz S: Clinical Pediatric Dermatology : A Textbook of Skin Disorders of Childhood and Adolescence. 2nd ed. Philadelphia: Saunders; 1993: 60, 469-70.
• Lin RL, Janniger CK: Pityriasis alba. Cutis 2005 Jul; 76(1): 21-4[Medline].
• Ortonne JP, Passeron T: Melanin pigmentary disorders: treatment update. Dermatol Clin 2005 Apr; 23(2): 209-26[Medline].
• Rakel RE, Bope ET: Conn's Current Therapy 2005. 57th ed. St Louis: WB Saunders; 2005: 999.
• Sams WM: Principles and Practice of Dermatology. New York: Churchill; 1990: 369.
• Vargas-Ocampo F: Pityriasis alba: a histologic study. Int J Dermatol 1993 Dec; 32(12): 870-3[Medline].

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