It is one of the diseases of the skin that have in common injuries that resemble dandruff, such as scales without obvious signs of inflammation.
Pityriasis types include: pityriasis rosea; pityriasis alba (also called pityriasis streptogenes, pityriasis simple, erythema streptogenes); Pityriasis rubra pilaris; And pityriasis versicolor (tinea versicolor).
What is pityriasis rosea?
Pityriasis rosea begins as a large pink spot that is found on the trunk of the body. The patch continues to appear one to two weeks later with the smaller pink spots in a “Christmas tree” shape.
Pityriasis rosea gives a mild itching in 50% of cases and disappears spontaneously in an average of six to eight weeks.
Pityriasis rosea is sometimes accompanied by mild symptoms similar to those of the flu and can mimic fungal infections and other conditions.
Pityriasis rosea does not have prolonged effects on health and is not directly contagious. Lifetime immunity often occurs after an episode.
Pityriasis rosea is a common rash that is usually seen in individuals between 10-35 years of age.
The rash usually lasts six to eight weeks, rarely extends 12 weeks or more. Once a person has pityriasis rosea, it usually does not recur again in his life.
Pityriasis rosea is characteristically characterized as an asymptomatic plaque pink, scaly, called “herald patch” or mother patch, which measures between 2 and 10 centimeters.
It is a pink to red-dry plate that appears on the back, chest, or neck and has a well-defined, scaly edge.
One or two weeks after the initial appearance of the herald patch, a person will then develop many small pink spots through their trunk, arms and legs.
This is characterized by hypopigmented patches, round to oval, on the face, arms, neck or shoulders. The patches vary in size, generally being a few centimeters in diameter.
The color is white or light pink. The scales are thin and adherent.
In general, the patches are clearly delimited; The edges may be erythematous and slightly raised. As a general rule, pityriasis is asymptomatic. However, there may be mild itching. The disease occurs mainly in children and adolescents.
The cause is unknown. Excessively dry skin after exposure to strong sunlight seems to be contributory. Efforts to find an infectious agent – bacterial, viral or fungal – have been unsuccessful.
Pitiriasis rubra pilaris
It is a chronic skin disease characterized by small follicular papules, disseminated yellowish-pink patches and, often, solid confluent palmoplantar hyperkeratosis.
The papules are the most important diagnostic feature, being more or less acuminate, reddish brown color, about the size of the head of the pinhead and crowned by a central horn plug. In the center of the horn a hair, or part of one, is usually fitted. The disease usually manifests first by scaling and erythema of the scalp.
The eruption is limited at the beginning, having a predilection for the sides of the neck and trunk and the extensor surfaces of the extremities.
Then, as new lesions occur, the extensive areas become patches of various sizes, which seem exaggerated and feel like a nutmeg grater.
Participation is generally symmetrical and diffuse with, however, small islands characteristic of normal skin within the affected areas.
Pitiriasis Versicolor (tinea versicolor)
In the upper trunk and extending towards the upper part of the arms, fine scales, gutatos or nummular patches appear, especially in young adults who transpire freely.
The individual patches are yellowish or brownish macules in pale skin, or hypopigmented macules in dark skin, with delicate scales. There may be slight itching and swelling of the patches.
This common fungal disease is more prevalent in the tropics where there is high humidity and high temperatures and frequent exposure to sunlight.
Is there any effective treatment?
In the few patients in whom the itching is severe enough to require treatment, there are a number of alternatives.
Slightly to moderately potent topical steroids and oral antihistamines (many of which are available without a prescription) will suffice.
Sometimes ultraviolet light administered in a doctor’s office or sunbathing carefully can decrease the itching enough to be tolerable.
The second stage of pityriasis erupts with a large number of oval points, ranging in diameter from 0.5 centimeters (size of a pencil eraser) to 1.5 centimeters (the size of a peanut).
This rash is usually confined to the trunk, arms, and legs, rarely occurring on the face and neck. Pityriasis is usually generated on the face, hands and feet.
Who is more prone?
Pityriasis is, for the most part, equally common in men and women. It usually occurs in children and young adults between 10-35 years of age. It does not have a racial predominance. Most people only develop pityriasis once in their life.
The exact cause of pityriasis remains unknown. Recently, pityriasis has been associated more strongly with a human herpes family virus called human herpes virus type 6 or 7.
Pityriasis is not caused by any type of herpes but it is known to be associated with common types of genital herpes, oral herpes or chicken pox.
While the mode of transmission (how it is passed between people) of pityriasis is also unknown, respiratory contact has been postulated.
Pityriasis does not appear to be directly or immediately contagious to close contacts or health providers exposed to the rash. Most people with a known exposure to pityriasis do not seem to get the rash.
How is it diagnosed?
Pityriasis is usually diagnosed only on the basis of its appearance, in particular the beginning of the distinctive patch of the large herald and the symmetrical presentation of the Christmas tree.
In addition, the herald’s patch tends to have a fine scale with a defined edge, the so-called “collarette”.
To rule out other types of skin disorders, a doctor can scratch the skin and examine the scales under a microscope to detect fungal infection that could mimic pityriasis.
In addition, blood tests including rapid plasma reagent (RPR) can be done to detect secondary syphilis, which can also mimic pityriasis. In some cases, a skin biopsy may be necessary to rule out skin conditions.
In rare cases, the rash may take other forms. Rounded protrusions (papular rash) can be seen in young children, pregnant women, and people with dark skin.
Blisters (vesicular erythema) can be seen in infants and young children. In some people, the herald’s patch may not appear, or two heraldic patches may appear together.
Before the herald patch appears, you may feel tired and like you have a cold. You may have a headache, nausea, sore throat and loss of appetite.
Pityriasis is similar to the rash seen in other skin conditions, including ringworm of the skin, tinea versicolor, eczema, and psoriasis.
A rash similar to pityriasis can also be caused by syphilis and by certain medications such as antibiotics.
If you have a rash on the palms of your hands or on the soles of your feet, consult your doctor. This may be a sign of something more serious than pityriasis.
Pityriasis disappears without treatment. It usually lasts around 6 to 8 weeks. If you have itching in the rash, you may want to use skin lotions and lubricants to soothe the itching.
If the symptoms are severe, your doctor may prescribe anti-inflammatory medications such as Corticosteroids to relieve itching and reduce the rash.
Although treatment is not necessary, antiviral medicines like Aciclovir can shorten the time you have the rash, especially if you take them when the rash first starts.
Exposing the rash to sunlight can make it disappear more quickly. But exposing your skin to the sun too long can result in sunburn and increase your risk of skin cancer.
If the rash lasts more than 3 months, contact your doctor.
To relieve itching at home:
Try to stay cool. Getting too hot and sweating can make the rash and itching worse.
Avoid taking showers or hot baths. Keep the water as cool as you can tolerate.
Add a handful of oats (ground to a powder) to your bath. Or you can try an oatmeal bath product, like Aveno.
Try a hydrocortisone cream without a 1% prescription for small itchy areas. Use the cream sparingly on the face or genitals. Note: Do not use the cream in children under 2 years old unless your doctor tells you to.
Do not use in the rectal or vaginal area in children under 12 unless your doctor tells you to.