The clinical picture of pityriasis alba was first described by the French physician Camille-Melchior Gilbert in 1860. Although the skin disease is not severe, it can be emotionally distressing for patients, most of whom are children. Although it has been known since the 19th century, its cause has not yet been determined.
What is pityriasis alba?
Harmless pityriasis alba usually affects children between the ages of six and twelve. Two to five percent of children in this age group suffer from the skin disease, which is sometimes chronic. Boys are slightly overrepresented. The non-infectious disease sometimes even occurs in adults. People with dark skin and their children have an increased risk of developing pityriasis alba. The disease manifests itself in the form of pale scales covered patches. At the site of these lesions, there is decreased skin pigmentation. It occurs due to the decreased activity of melanocytes. They form fewer and smaller melanosomes. The pigment disorder is found mainly on the face, but also on the body and there usually with larger patches. In some young children, pityriasis alba first appears after prolonged sunbathing without adequate sunscreen or in child patients who are frequently hot bathed. Histologically, the skin disorder is a form of interstitial dermatitis in which the melanocytes are degeneratively altered.
Causes
The exact cause of pityriasis alba is still unknown. Some physicians consider it to be a mild form of atopic eczema because its lesions resemble reddish atopic dermatitis patches in the early stages, only later becoming paler and then standing out sharply from the surrounding skin color. Some physicians suspect excessive use of corticosteroid creams in the treatment of eczema as the cause of hypopigmentation. Other physicians consider pityriasis alba to be an attenuated form of normal eczema caused by an excessive immune response.
Symptoms, complaints, and signs
The reddish lesions are not sharply demarcated and are covered with fine skin flakes that develop into pale dry patches on the facial skin. The pale areas are not completely depigmented, but merely hypopigmented. The predominantly round, oval, or map-like discolorations, 0.5 to 2 cm in diameter, are sometimes associated with severe itching and sebaceous gland atrophy. On the face, they are usually located on the sides of the cheeks and forehead. On the body, larger lesions with accentuated margins are usually found. Four or five, and in extreme cases even more than 20 such skin lesions are present there. About one fifth of pityriasis alba patients have the conspicuous patches on the shoulders, extensively on the extensor sides of the upper arms and on the neck. The skin disease disappears at the latest when the patient enters adulthood. Until that time, however, it recurs in some of the childhood patients.
Diagnosis and course of the disease
The course is usually chronic and occurs in three stages: at the beginning, the patient recognizes a faintly reddened slightly raised scaly skin area. Thereafter, the raised lesion fades. Finally, a pale flat smooth area of skin remains. Healing of pityriasis alba sometimes takes several months. In some patients, the healing process takes up to 10 years. In summer, the area remains pale despite the tanning of the rest of the skin. Pityriasis alba is diagnosed in a thorough examination of the skin surface of the face and, if necessary, the entire body. To differentiate it from pityriasis versicolor alba, tinea corporis and tinea faciei, the physician performs the potassium hydroxide (KOH) test. The distinction from vitiligo (white spot disease) can already be made by the external appearance: In the latter, the white spots are always found only in the mouth and eye area. In addition, in this skin disease, the light spots are completely depigmented and therefore also appear white.
Complications
As a rule, pityriasis alba is not life-threatening or particularly hazardous to health. However, this disease causes considerable discomfort to the skin of the affected person. Most patients are ashamed of the discomfort and therefore feel uncomfortable with their skin.Bullying and teasing can also occur as a result, especially at a youthful age. Furthermore, pityriasis alba can also lead to depression or other psychological upsets and limitations. As a result of the disease, the skin itself is covered with red patches and in some cases those affected suffer from hypopigmentation. Permanent itching of the skin can also significantly reduce the quality of life of the affected person. Especially on the face or neck, the discomfort of pityriasis alba can be very unpleasant. Treatment of pityriasis alba can be done with the help of medication and usually leads to success. Complications do not occur in the process. However, a completely positive course of the disease cannot be guaranteed in every case. It is possible that the symptoms of pityriasis alba may recur. Scars may also form on the skin as a result of this disease.
When should one go to the doctor?
When the characteristic skin patches appear, a doctor should be consulted. Reddish, slightly scaly skin patches that appear in groups of four to five patches indicate pityriasis alba, which is best clarified quickly. If a rash appears on the neck and arms at the same time, immediate clarification is necessary, as a severe form of the skin condition may be present. In the case of mild forms, the doctor must prescribe a medical preparation. This is usually sufficient for the spots to disappear within a few days. People who suffer from dry skin are particularly likely to develop pityriasis alba. People with pediatric eczema and other skin diseases are also among the risk groups and should go to their family doctor or dermatologist with the symptoms mentioned. Further contacts are the internist or a therapist, if the skin changes cause psychological problems. In addition, in the case of protracted complaints that cannot be alleviated by conservative measures, an alternative medical practitioner can be involved in consultation with the physician.
Treatment and therapy
Pityriasis alba is sometimes not treated at all, as the spots heal on their own. Otherwise, therapy is only symptomatic: the patient is given a moisturizing skin cream to combat the dryness and scales. Creams with low-dose hydrocortisone are also applied to the itchy and scaly areas. Other dermatologists treat pityriasis alba with ointments containing urea to make the scales come off. Child patients over the age of two are sometimes also given the immunosuppressants tacrolimus 0.1 percent and pimecrolimus (1 percent) to speed up the healing process. The creams stop the release of neurotransmitters that cause the eczema. In severe cases, the patient receives PUVA therapy with psoralen and long-wave UV-A light or longer-lasting laser therapy. In summer, the person affected by pityriasis alba does not go out in the sun at all or covers the light lesion with a sunscreen with a high sun protection factor so that the hypopigmented skin area is not further damaged. Also, he should not wash his skin with normal soap, as it irritates the skin even more, but only use an O/W emulsion or a hydrophilic oil. If the noticeable skin lesion still does not disappear after some time, he can also cover it cosmetically so that it is no longer so obvious, at least temporarily.
Outlook and prognosis
In the presence of pityriasis alba, a positive prognosis can practically always be expected. This skin disease almost always heals on its own. However, the affected areas of skin remain conspicuously pale for some time. However, this pigment disorder also diminishes with time. The reason for this skin disease has not yet been clarified. Pityriasis alba is not contagious. It is obviously favored by dry skin and cold, dry air. However, it is not known why this leads to bright red, slightly scaly skin redness. In some cases there is already a predisposition to atopic dermatitis, but in others there is not. Children are almost always affected by pityriasis alba. Rather rarely it also affects adults. The course of pityriasis alba varies from individual to individual. Some sufferers have only one episode with an asymptomatic course. In others, several relapses occur in succession. The lingering of lighter skin areas can also take different lengths of time.In sum, however, these differences do not change the positive prognosis of pityriasis alba. As a rule, pityriasis alba does not even require a visit to the doctor. If this is nevertheless done because of the extent of the scaly skin patches, the doctor will probably not initiate any treatment. At best, a light hydrocortisone gel will help.
Prevention
Because the exact cause of pityriasis alba is unknown, no prophylactic measure is possible.
What you can do yourself
Because pityriasis alba usually resolves on its own, no medical treatment is needed. Parents of affected children must ensure that the child does not scratch the skin eczema. In addition, the affected areas should be cooled regularly. Affected children are usually very irritated and sensitive to pain. This makes a calm demeanor on the part of the parents all the more important. Somewhat older children can be explained the causes and symptoms of pityriasis alba. This often contributes to the fact that the children scratch the skin areas less frequently and thus contribute to a rapid healing of the symptoms. Good personal hygiene is essential to quickly overcome the condition. In addition to ointments prescribed by a doctor, natural remedies can also be used if necessary. Lotions with aloe vera relieve itching and help against dandruff. The use of these remedies should be discussed with the pediatrician beforehand. Otherwise, allergic reactions may occur. It is also important to provide sufficient sun protection for the entire skin. This can reduce the color differences on the arms and legs as well as on the face. In severe cases, the spots can be covered by means of cosmetic products.
