Pityriasis rosea is a relatively common skin rash that causes a rash characterized by reddish or pink patches that cause intense itching. Their causes are not fully understood but it is believed that the disease has a viral origin.
Pityriasis rosea is a skin rash probably caused by some viruses of the family of human herpesviruses such as human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7), they causing in children a disease called sudden rash, also known as infantile roseola.
The sudden rash and pityriasis rosea are different diseases caused by the same virus. The sudden exanthema is characterized by being a skin rash and high fever with no itching, while pityriasis is a skin rash without fever, but with intense itching.
Despite being caused by some members of the human herpesvirus family of viruses, pityriasis rosea has nothing to do with cold sores or genital herpes, which are diseases caused by other viruses in this family, including the human herpesvirus 1 (HHV-1) and human herpesvirus 2 (HHV-2).
Despite being a likely viral disease, pityriasis rosea is not contagious. This rash can occur at any time of life, but is most common between 10 and 35 years of age and is rare in babies and the elderly. It more common in women than in men, and the months of autumn and spring are the seasons in which the disease appears most often.
Up to 90% of cases pityriasis rosea begin with a single lesion, called the motherboard or medallion, which features rounded or oval shape, with 2-5 cm in diameter, well-defined edges and pink color. In darker-skinned individuals, the injury can be purple or gray. With each passing day, the motherboard grows, he begins to be a thin peeling and its center becomes clearer. Abdomen, chest and back are the most common locations of this initial injury.
Some patients report the appearance of some unspecific symptoms of virus days before the onset of the motherboard. The most common are a sore throat, malaise, headache, diarrhea or body aches.
With each passing day, it begins the so-called eruptive period, also known as secondary rash. This stage is the appearance of multiple lesions similar to the motherboard, but smaller. In general, these injuries daughters are restricted to the trunk and the root of the legs being very common the involvement of the groin region. The involvement of the neck, face, hands and feet can occur, but is unusual because the lesions tend to be centered on the center of the body, saving the ends.
The number of daughters lesions may vary from tens to hundreds, depending on the intensity of the rash. This multiple lesions are also reddish, fine scaling feature and can be very itchy. In some cases, the mother injury is much higher than the daughters lesions, but in others, it may be only slightly larger. After the start of the eruption period, the patient may be taking new lesions rash even for several days, sometimes weeks.
As injuries are becoming old, they begin to have a clearer center and a halo around with flaking. After 4 to 6 weeks, the earliest lesions begin to fade but may leave a depigmented area (whiter the skin), which can last months to return to normal color. The darker the skin, the more evident is that depigmentation.
In addition to the skin lesions, itching is the only symptom that usually causes pityriasis rosea. The intensity of the itching varies from person to person. In most cases, itching is mild to moderate, but the 1 out of 4 patients ranked his itching as intense.
Pityriasis rosea heal spontaneously but can take. Counting from the motherboard rise to the disappearance of the last lesions of secondary rash, the disease can take 4-12 weeks duration.
If the rash lasts more than three months to disappear, the diagnosis of pityriasis rosea should be rethought. In general, it indicates a skin biopsy to confirm the diagnosis.
Once the eruption period has arisen, the diagnosis of pityriasis rosea usually relatively simple. A story of a mother lesion, with fine scaling and pale center, a few days preceding the emergence of an itchy rash with no other symptoms is a very typical presentation of pityriasis rosea.
The diagnosis can be more complex in unusual cases or when the mother's injury is still at a very early stage. In about 10% of cases, there is the motherboard preceding the eruptive period, which makes the diagnosis a little more difficult.
Some diseases can be confused as pityriasis rosea, and the dermatophytosis (fungal skin lesions), secondary syphilis and guttate psoriasis the most similar. Some drug allergies can also cause lesions similar to those of pityriasis rosea. HIV is another differential diagnosis to be thought of atypical cases.
In most cases it is not necessary to perform additional tests. If the doctor, however, find that the clinical picture is not very typical, some tests to rule out the differential diagnosis may be required, such as VDRL research or FTA-ABS syphilis, HIV serology and mycological skin examination to rule fungi.
There is no specific treatment for pityriasis rosea. The disease-curing spontaneously and without sequelae after 2 or 3 months, regardless of what is done.
Treatment is usually indicated for those patients who complain of itchy. Ointments or creams based on average power corticosteroids such as hydrocortisone, mometasone or triamcinolone help relieve itching. These creams can be applied 2 to 3 times a day for up to 3 weeks to minimize the risk of adverse effects.
Topical lotions with menthol or calamine also help and have less risk of causing side effects than corticosteroids.
Antihistamines by mouth also help. If the patient has trouble sleeping due to the itching, antihistamines grandfather, causing sleep, such as hydroxyzine can be used.
Once the rash and itching have disappeared, it is a rare disease recurrence.
