Pityriasis alba
Encyclopedia
Pityriasis alba is a common skin condition mostly occurring in children and usually seen as dry, fine-scaled, pale patches on the face. It is self-limiting and usually only requires use of moisturizer creams.
The condition is so named for the fine scaly appearance initially present (pityriasis
) and the pallor of the patches that develop (while "alba" is Latin for white, the patches in this condition are not totally depigmented).
may heal leaving pale skin, as may excessive use of corticosteroid
creams used to treat episodes of eczema
. The hypopigmentation is due to both reduced activity of melanocyte
s with fewer and smaller melanosome
s.
The condition is most often seen in children between the ages of 3 and 16 years and is more common in males than females.
It may occur more frequently in lighter-skinned patients, but is more apparent in those with darker complexions.
Up to a third of US school children may at some stage have this condition. Single-point prevalence studies from India have shown variable rates from 8.4%,
to 31%.
Other studies have shown prevalence rates in Brazil of 9.9%,
Egypt 13.49%,
Romania 5.1%,
Turkey 12% where higher rates were seen in those with poor socioeconomic conditions,
and just 1% in school children in Hong Kong.
Individual lesions develop through 3 stages and sometimes are itchy:
Lesions are round or oval, of 0.5-2 cm in size although may be larger if they occur on the body (up to 4 cm), and usually number from 4 or 5 to over 20. The patches are dry with very fine scales. They most commonly occur on the face (cheeks), but in 20% appear also on the upper arms, neck, or shoulders.
The diagnostic differential should consider tinea and vitiligo amongst other causative factors.
The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used.
As the patches of pityriasis alba do not darken normally in sunlight, effective sun protection helps minimise the discrepancy in colouration against the surrounding normal skin. Cosmetic camouflage may be required.
Tacrolimus
or [Terrasil] have been reported as speeding resolution.
In exceptionally severe cases PUVA
therapy may be considered.
The condition is so named for the fine scaly appearance initially present (pityriasis
Pityriasis
Pityriasis commonly refers to flaking of the skin. The word comes from the Greek πίτυρον "bran".-Classification:Types include:* Pityriasis alba* Pityriasis lichenoides chronica* Pityriasis lichenoides et varioliformis acuta...
) and the pallor of the patches that develop (while "alba" is Latin for white, the patches in this condition are not totally depigmented).
Etiology
There is no specific known cause for this condition, but public swimming pools could be a factor. Any dermatitisDermatitis
-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...
may heal leaving pale skin, as may excessive use of corticosteroid
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
creams used to treat episodes of eczema
Eczema
Eczema is a form of dermatitis, or inflammation of the epidermis . In England, an estimated 5.7 million or about one in every nine people have been diagnosed with the disease by a clinician at some point in their lives.The term eczema is broadly applied to a range of persistent skin conditions...
. The hypopigmentation is due to both reduced activity of melanocyte
Melanocyte
-External links: - "Eye: fovea, RPE" - "Integument: pigmented skin"...
s with fewer and smaller melanosome
Melanosome
In a biological cell, a melanosome is an organelle containing melanin, the most common light-absorbing pigment found in the animal kingdom.Cells that synthesize melanins are called melanocytes, and also the retinal pigment epithelium cells, whereas cells that have merely engulfed the melanosomes...
s.
The condition is most often seen in children between the ages of 3 and 16 years and is more common in males than females.
It may occur more frequently in lighter-skinned patients, but is more apparent in those with darker complexions.
Up to a third of US school children may at some stage have this condition. Single-point prevalence studies from India have shown variable rates from 8.4%,
to 31%.
Other studies have shown prevalence rates in Brazil of 9.9%,
Egypt 13.49%,
Romania 5.1%,
Turkey 12% where higher rates were seen in those with poor socioeconomic conditions,
and just 1% in school children in Hong Kong.
Symptoms and signs
The dry scaling appearance is most noticeable during the winter as a result of dry air inside people's homes. During the summer, tanning of the surrounding normal skin makes the pale patches of pityriasis alba more prominent.Individual lesions develop through 3 stages and sometimes are itchy:
- Raised and red - although the redness is often mild and not noticed by parents
- Raised and pale
- Smooth flat pale patches
Lesions are round or oval, of 0.5-2 cm in size although may be larger if they occur on the body (up to 4 cm), and usually number from 4 or 5 to over 20. The patches are dry with very fine scales. They most commonly occur on the face (cheeks), but in 20% appear also on the upper arms, neck, or shoulders.
The diagnostic differential should consider tinea and vitiligo amongst other causative factors.
Treatment
No treatment is required and the patches in time will settle.The redness, scale and itch if present may be managed with simple emollients and sometimes hydrocortisone, a weak steroid, is also used.
As the patches of pityriasis alba do not darken normally in sunlight, effective sun protection helps minimise the discrepancy in colouration against the surrounding normal skin. Cosmetic camouflage may be required.
Tacrolimus
Tacrolimus
Tacrolimus is an immunosuppressive drug that is mainly used after allogeneic organ transplant to reduce the activity of the patient's immune system and so lower the risk of organ rejection...
or [Terrasil] have been reported as speeding resolution.
In exceptionally severe cases PUVA
PUVA
PUVA is a psoralen + UVA treatment for eczema, psoriasis, graft-versus-host disease and vitiligo, and mycosis fungoides. The psoralen is applied or taken orally to sensitize the skin, then the skin is exposed to UVA. Long term use has been associated with higher rates of skin cancer.Psoralens are...
therapy may be considered.
Prognosis
The patches of pityriasis alba may last from 1 month to about one year, but commonly on the face last a year.See also
- VitiligoVitiligoVitiligo is a condition that causes depigmentation of sections of skin. It occurs when melanocytes, the cells responsible for skin pigmentation, die or are unable to function. The cause of vitiligo is unknown, but research suggests that it may arise from autoimmune, genetic, oxidative stress,...
which, by comparison, causes total loss of skin colour or on the face tends to occur around the mouth and eyes. - List of cutaneous conditions