pityriasis rosea Treatment and explanation

pityriasis rosea treatment, described by M. Gibert in 1860, is an acute eruptive skin disease, frequent, mild and self limiting. Its clinical diagnosis is easy, except in the atypical forms, very different but very few. Its etiology is not established but appears infectious viral. The therapeutic measures to prevent inadvertent or unnecessarily aggressive.

EPIDEMIOLOGY

Pityriasis rosea is very common worldwide. It affects almost equally in both sexes. The achievement may be at any age, but especially in children and young adults (75 per 100 cases occur between 10 and 35). Our temperate countries observe an increase in the fall or spring, sometimes in the winter and a scarcity in the summer. There is no outside factor favoring, perhaps, of atopy or recent infection. It is reported the possibility of a few cases occurring in series in a family or in small communities and a frequency slightly higher among dermatologists than other doctors, which raises the possibility of a low infectiousness.

TYPICAL FORM

In the typical form (80 p. 100 of cases), the precursors are usually absent. Times are reported general malaise, fever, headache, joint pain, digestive problems or a few lymph nodes.

The original plate is the first event observed in 50 to 90 per 100 cases. This plate, usually single seat on the trunk or root of a limb extension centrifugal him in a few days to reach a diameter of 3 to 5 cm or more. It is rounded or oval, although limited, its center is wrinkled, pale pink, its border is slightly papular, darker pink and finely scaly. This border is separated from the central area by a thin flange desquamative whose free edge is internal. The original plate remains isolated for 5 to 15 days, sometimes longer.

The secondary eruption occurs in successive crops, while the original plaque is still present, and reaches its maximum in about ten days. It is composed of two types of elements:

- Oval medallions, although limited, with a diameter of 1 to 2 cm, reproducing the original plate and smaller;

- Multiple erythematous macules, smooth, sometimes finely scaly, a few millimeters in diameter, may develop into a medallion.

The topography is characteristic symmetrical, it mainly affects the trunk orientation with medallions along the lines of tension of the skin, giving back an image in "Christmas tree". Are frequently affected the proximal limbs and neck. The face is usually respected.

Pruritus is absent in one quarter of cases, mild in half of cases and important quarter of the cases.

There is no other sign useful in diagnosis, in the usual way. Signs previously reported as very rare in the prodromal phase can sometimes be seen during the eruptive phase, but with a frequency not significantly. Biological changes are absent or nonspecific.

The development is self-limiting in 3-6 weeks on average. The skin lesions disappear, starting with the oldest and sometimes leaving a hypo-or hyperpigmentation transient. However, local treatments can complicate this evolution nuisance, causing irritation and itching eczematisation. A impetiginisation may also be the consequence, as the primary pruritus associated with the eruption. Recurrences are very rare (2 to 3 per 100 cases), usually only a few months or years.

ATYPICAL FORMS

Their multiplicity of atypical forms (20 p. 100 of cases) only allows to list the main, unable to detail them here.

The original plate may be absent or multiple or remain the only manifestation.

The topography of the rash may be atypical localized, unilateral, affecting the extremities, face, scalp, genitals, palms, plants, nails, oral mucosa (16 per 100 cases).

The morphology of the eruption may be secondary psoriasiform, vesicular, papular, urticarial or purpuric, pustular or bullous.

The duration of the rash may be a few hours to two months for the original plate and 1 week to 3 months for the secondary eruption.

The terrain favors certain variants. The child is more exposed to vesicular forms, hives and facial. The subject black has often profuse eruptions, lichenoid or vesicles, a distribution device, a polyadenopathy superficial residual hyperpigmentation and recurrences quite common. Positivity associated HIV status induces an alteration of general condition with fever, rash guard, but its typical form. Pregnancy does not feature and pityriasis rosea does not sound on the fetus.

TESTING

The diagnosis of pityriasis rosea is based on the clinic and requires no further examination in the usual way. The biological constants are not changed or occasionally, but not significantly. In the current state of our knowledge, viral serologies are not used for diagnosis.

Only in the differential diagnosis, which is out of our way, and in the presence of an atypical form, we will use some reviews:

- Syphilis serology, to eliminate secondary syphilides;

- A mycological examination, to rule out dermatophytosis;

- A skin biopsy for histopathological study to discuss many differential diagnoses, remembering that the histological pityriasis rosea pictures are nonspecific and eczema type: parakeratosis in islets, spongiosis and intraepidermal vésiculisation, sometimes dyskeratotic keratinocytes or multinucleated; edema, perivascular infiltrates lympho-histiocytic and extravasation of red blood cells in the superficial dermis. The histological changes are identical to the original level of the plate and the secondary eruption.

ETIOLOGY

It is necessary to raise this issue before addressing the treatment, although to date the etiology is not known. After proposing various etiological hypotheses (contact clothing, psychosomatic, autoimmune, fungal, bacterial, atopy), it is now to retain an infectious virus and more precisely. The epidemiological and clinical characteristics of the disease are suggestive of the origin of the virus-like structures intrak?ratinocytaires were observed by electron microscopy, and a typical disease could be transmitted through extracts of dander original plate. However, to date, serological and virological studies are not conclusive enough. The virus candidate most often implicated is currently HHV-7 [4], but all studies are not consistent. To date, the virus responsible is not supposed to identify.

Toxidermia to the type of pityriasis rosea should be considered as differential diagnoses, if one sticks to the hypothesis of an infectious viral disease. They are rare and have certain clinical features: pruritus usual lack of plate initial lesions larger, fewer, scaly, sometimes lichenoid, of longer duration, often pigmentog?nes, reached the mouth more often. The evolution is variable, often prolonged, or dose-dependent, or regressive despite continued treatment, while in others the rash does not go to the end of treatment, the test is sometimes positive reintroduction. The drugs involved are usually captopril, gold salts or clonidine, metronidazole, barbiturates, ketotifen, omeprazole, penicillamine, and sometimes beta-blockers, isotretinoin, griseofulvin, the BCGtherapy, interferon a-2a, hepatitis B vaccine

TREATMENT

The treatment is rendered useless by spontaneous recovery. He must avoid unwanted medication, which transform a benign dermatosis in a larger (eczematisation)

USUAL SIMPLE FORMS

In the common forms, asymptomatic and limited pityrisasis Rosea, will be understood from the foregoing, no treatment is necessary abstention is desirable. Must still obtain the support of the patient to this option because it is concerned by the unexplained rash, and he often complains of his character or display of pruritus.

First, reassure the patient

This step is essential to explain to make him understand the natural history of pityriasis rosea, character Benin exceptionally contagious and resolved spontaneously within a few weeks, hence the need for some patience confident.

Assess the importance of pruritus

The itching is actually quite common and its intensity is highly variable. Sometimes it is more a manifestation of fear vis-?-vis the disturbing finding of the eruption, the patient presents as pruritus. Moreover, pruritus is an authentic manifestation of the functional dermatitis. The itching may be mild, intermittent, without effects on either the daytime activities on sleep, also its biggest impact will be characterized as moderate, medium or intense.

In case of slight itching, applications will be limited to talc, emollient, non-greasy topical of such a paste with water, a calamine lotion.

If the itching is annoying, it will use topical corticosteroids of class II or III that cause no risk of aggravation of the eruption. We can add an anti-H1 antihistamine orally but whose efficacy is often disappointing here.

When there is a frank eczematisation of the eruption, accompanied by an annoying itch, we will address this eczematisation as such by topical corticosteroids and / or emollients.

ERUPTIONS INTENSE

In some rare cases, the importance of skin disease may justify the use of complementary methods of treatment: they are in particular very large eruptions, vesicular forms, pruritus rebels and painful.

UVB phototherapy

The effectiveness of UVB has long been known and confirmed by various publications, including controlled studies of hemi-body irradiation, the patient being his own control. The irradiation must be sufficient to cause erythema and desquamation. UVB administered five days a week for 1-2 weeks, starting at 80 per 100 of the minimal erythema dose (MED) UVB. The dose is then increased by 20 per 100 in the absence of erythema, 10 p. 100 if the rash is mild, it does not increase the dose if rash is moderate or severe and the treatment is suspended in case of severe erythema.

The results are good if treatment is started within the first week of the eruption, whose total duration is shortened is followed. Pruritus may quickly disappear early in treatment but this result is inconsistent, according to the authors. The broad-spectrum UVB and narrowband UVB (311 nm) have similar efficacy. A significant risk of this therapy should be recalled and reported to the patient: the possibility of residual post-inflammatory pigmentation, especially as the skin is more pigmented. This treatment is therefore to be considered with caution.

Note that the PUVA (3 sessions per week for a total dose of 20 J/cm2) was also used by some [2], with the same success in the same time, without controlled trial published. However, this method has the constraints and disadvantages of chemotherapy associated with UVA. So what UVB should be preferred here.

Erythromycin

A double-blind study against placebo was conducted in 90 patients. The treatment consisted of 1 g / day erythromycin orally four times daily for 14 days in adults (25 to 40 mg / kg / day in children). This treatment has obtained 73 per 100 complete responses, without side effects or relapse after discontinuation of treatment against no response in the placebo group.

Corticosteroids

In severe cases, systemic corticosteroids has been proposed: 15 mg / d of oral prednisone, or a single intramuscular injection of 40 mg triamcinolone. Despite some favorable results, this treatment seems cons-indicated due to risk of exacerbation of the rash if treatment is early relapse or rebound upon discontinuation of treatment.

Pityriasis Rosea Treatment

The indication "Pityriasis Rosea" is mentioned as such in any of the therapies we have cited. Of course, the prescription of a topical corticosteroid or an oral antihistamine is commonly admitted for inflammatory and pruritic dermatitis. The disease is not recognized indications of erythromycin or oral corticosteroids.

UV light therapy may be supported after prior agreement as a purely pathological event outside the accepted indications for PUVA K2E with the listing or, if the disease requires two or more fields per session, K3, the 5E sitting