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Dermatology > DISEASES OF PIGMENTATION
Pityriasis Alba
Article Last Updated: Apr 3, 2006
AUTHOR AND EDITOR INFORMATION
Section 1 of 11  
Author: Mohsin Ali, MBBS, FRCP, MRCP, MRCPI, Consulting Staff, Department of Dermatology, Amersham General Hospital, UK
Coauthor(s):
Bassam Zeina, MD, PhD, Consulting Staff, Department of Dermatology, Milton Keynes Hospital, United Kingdom;
Sohail Mansoor, MBBS, MSc, Dermatologist and Lead Physician in Dermatologic Surgery, Department of Dermatology, Barnet Hospital, London, UK
Editors: Mark G Lebwohl, MD, Chairman, Department of Dermatology, Mount Sinai School of Medicine; David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Director, Division of Dermatology, Scott and White Clinic; Director Dermatology Residency Training Program, Scott and White Clinic; Christen M Mowad, MD, Assistant Professor, Department of Dermatology, Geisinger Medical Center; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Author and Editor Disclosure
Synonyms and related keywords:
erythematous scaly patches, hypopigmentation, atopic dermatitis
Background
Pityriasis alba is a nonspecific dermatitis of unknown etiology that causes erythematous scaly patches. These resolve and leave areas of hypopigmentation.
Pathophysiology
Pityriasis alba has been regarded as a manifestation of atopic dermatitis. It is known to occur in nonatopic individuals.
Frequency
United States
The frequency both in the United States and internationally is unknown.
Mortality/Morbidity
Pityriasis alba is not associated with increased mortality. The lesions commonly are asymptomatic, although some patients report burning or pruritus.
Race
Pityriasis alba can affect persons of any race, but it may be more prominent in dark-skinned patients.
Sex
Both sexes are equally susceptible.
Age
Pityriasis alba occurs predominantly in children aged 3-16 years.
History
- Erythema may initially be conspicuous, and minimal serous crusting may even occur at a few points on the surface of some of the plaques.
- Erythema later subsides completely.
- At the stage when a physician commonly observes lesions, they show only persistent fine scaling and depigmentation. This commonly induces the patient to seek advice.
- It may be conspicuous in heavily pigmented skin. In lighter skins, it may become conspicuous after sun tanning.
- The course is extremely variable. Most cases persist for several months, and some still show leukoderma for a year or more after all scaling subsides.
- Recurrent crops of new lesions may develop at intervals.
- The average duration of the common facial form in childhood is a year or more.
- Widespread cases overlap with a condition termed progressive and extensive hypomelanosis.
Physical
- The individual lesion is a rounded, oval, or irregular plaque that is red, pink, or skin colored and has fine lamellar or branny scaling.
- Several patches are usually observed.
- Lesions usually range from 0.5-2 cm in diameter but may be larger, especially on the trunk.
- In children, the lesions are often confined to the face and are most common around the mouth, chin, and cheeks.
- In 20% of affected children, the neck, arms, and face are involved.
- Less commonly, the face is spared and scattered lesions are observed on the trunk and limbs.
Causes
The cause is unknown. The condition has been regarded as a manifestation of atopic dermatitis.
Leprosy
Psoriasis, Plaque
Vitiligo
Other Problems to be Considered
Discoid eczema
Hypopigmented mycosis fungoides
Histologic Findings
Histologic changes are unimpressive. Acanthosis and mild spongiosis is observed, with moderate hyperkeratosis and patchy parakeratosis. Follicular plugging, spongiosis, and sebaceous gland atrophy may be observed. On electron microscopy, reduced numbers of active melanocytes and a decrease in number and size of melanosomes is observed in affected skin.
Medical Care
Pityriasis alba resolves spontaneously and may not require treatment.
- Treatment includes a simple emollient cream.
- For chronic lesions on the trunk, a mild tar paste may be helpful.
- Topical 1% hydrocortisone preparations may be helpful if mild inflammation is present.
Consultations
A dermatologist may be consulted for cosmetic camouflage.
Diet
No dietary recommendations are currently proposed.
Activity
No specific activity limitations or exercises are recommended. Photoprotection may be considered.
Response to treatment often is disappointing.
Drug Category: Emollients
A variety of lotions, creams, and ointments that contain hydrocarbons, oil, waxes, and long-chain fatty acids aid in retaining moisture in the skin especially if applied immediately after bathing. A bland emollient may be used to reduce the scaling.
| Drug Name | Aqueous cream (Curel, Cetaphil, Nivea, Lubriderm) |
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| Description | Oil in water emulsion that spreads easily and helps retain moisture in the skin. |
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| Adult Dose | Apply 2-6 times/d |
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| Pediatric Dose | Administer as in adults |
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| Contraindications | Documented hypersensitivity |
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| Interactions | None reported |
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| Pregnancy | A - Safe in pregnancy
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| Precautions | None reported |
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Drug Category: Corticosteroids, topical
Reducing inflammation helps reduce symptoms and helps resolve lesions.
| Drug Name | Hydrocortisone (Cortaid, Dermacort) |
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| Description | 1% or 2.5% hydrocortisone cream or ointment. Adrenocorticosteroid derivative suitable for application to skin or external mucous membranes. Has mineralocorticoid and glucocorticoid effects resulting in anti-inflammatory activity. |
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| Adult Dose | Apply to face bid for 1 wk or until lesion improves |
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| Pediatric Dose | Apply as in adults |
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| Contraindications | Documented hypersensitivity; viral, fungal, and bacterial skin infections |
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| Interactions | None reported |
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| Pregnancy | C - Safety for use during pregnancy has not been established.
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| 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 |
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Further Inpatient Care
- Inpatient care is not generally required.
Further Outpatient Care
- Regular follow-up is not required.
Transfer
- Patients requiring cosmetic camouflage may require transfer to another specialist if the dermatologist or primary care physician teams cannot provide this service.
Deterrence/Prevention
- Prevention is not possible because the etiology of pityriasis alba is unknown.
Prognosis
- The prognosis is good because pityriasis alba almost always resolves spontaneously.
Patient Education
- Provide education relating to the benign nature of pityriasis alba.
- For excellent patient education resources, visit eMedicine's Skin, Hair, and Nails Center.
Medical/Legal Pitfalls
- Misdiagnosis because a patient may have leprosy or hypopigmented mycosis fungoides: Additional investigation may be necessary.
- Failure to reexamine patients before repeatedly refilling patients' steroids: Steroid side effects may progress to the point of permanent damage without appropriate surveillance.
- Failure to consider a new problem when a patient, who was previously doing well, suddenly seems to worsen: Allergic contact dermatitis may develop with any topical therapy (including steroids), and irritant dermatitis may likewise develop.
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Pityriasis Alba excerpt Article Last Updated: Apr 3, 2006
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