Disease Index Skin Diseases

Pityriasis rosea

Pityriasis rosea is a papulosqamous, self limiting condition, seen usually in adolescents and young adults. Pityriasis typically begins with an erythematous ‘herald’ patch, which may appear anywhere on the body, although it occurs most commonly on the trunk.

Pityriasis rosea is a papulosqamous, self limiting condition, seen usually in adolescents and young adults. The etiology is unknown; however, it may be of viral origin. The lesions usually disappear in 6 to 8 weeks.

Aetiology of Pityriasis rosea

Pityriasis rosea is common, particularly, in the autumn and winter. It affects women possibly a little more frequently than men and is more usual between the ages of 10 and 35 years, although it has been reported in the very young and the very old. The histology is that of eczema, but its aetiology is obscure. Most favour a viral cause, because second attacks are unusual, which suggests the acquisition of immunity.

Small epidemics have occurred and dermatologists are four times more at risk than their ENT colleagues. However, outbreaks among associates of the patient are exceptional. Interest is centering on herpes simplex virus type 7 (HHV-7), a ubiquitous virus that exhibits tropism for the CD4’T cell. Eighty percent of infants have evidence of infection with this virus but primary infection may occur later; viral foot prints have been reported in associated with Pityriasis rosea but not in controls or once the patient has recovered. HHV-7 DNA sequences have been isolated from the skin and plasma from patients with acute Pityriasis rosea, but further studies are required to confirm the connection.

Pathophysiology of Pityriasis rosea

Various factors support a viral origin, including a predilection for fall and spring months, increased incidence among immuno-compromised persons, lifelong immunity after the rash, and case clusters. Human herpes virus-6 (HVV-6) or HHV-7 may be the inciting factor, although a definitive association remains controversial. A PR-like rash may appear in conjunction with use of medications such as captopril, metronidazole, clonidine, and barbiturates.

Signs and symptoms

Pityriasis typically begins with an erythematous “herald” patch, which may appear anywhere on the body, although it occurs most commonly on the trunk. Although this slightly raised, oval lesion is about 2 to 6 cm in diameter, approximately 25% of patients don’t notice it.

A few days to several weeks later, yellow tan or erythematous patches with scaly edges (about 0.5 to 1 cm in diameter) erupt on the trunk and extremities – and, rarely, on the face, hands, and feet in adolescents. Eruption continues for 7 to 10 days, and the patches persist for 2 to 6 weeks.

Occasionally, these patches are macular, vesicular, or Urticarial. A characteristic of this disease is the arrangement of lesions, which produces a pattern similar to that of a pine tree. Accompanying pruritus, if present, is usually mild but may be severe.

Differential Diagnosis for Pityriasis rosea

The herald patch

The herald patch on its own is a difficult diagnosis. The differential is that of any annular or discoid patch, especially ringworm.

  • Tinea: – In ringworm, particularly animal ringworm, the margin of the annular patch is more inflammatory, scaly and raised and there is a tendency for central healing. Scrapping of the skin mounted in potash should reveal hyphae. However, if the peripheral collarette of scale is detected and pityriasis rosea is suspected, the diagnosis may be confirmed when the rest of the eruption develops a few days later.

Trunk eruptions

There are a number of eruptions involving the trunk that can cause diagnostic confusion.

  • Secondary syphilis: – The patient is generally unwell. There is lymph adenopathy and the rash involves the face, genitalia and palms as well as the torso. It does not itch and the serology will be positive.
  • Pityriasis versicolor: – These conditions are often confused simply because of their name. In Pityriasis versicolor, the lesions are fawn coloured or off white and asymmetrical with a tendency to confluence, as opposed to pink and oval and following a herald patch in pityriasis rosea. Both conditions favour the trunk but Pityriasis versicolor is slow and insidious in its evolution and not acute like pityriasis rosea.
  • Guttate psoriasis: – Guttate psoriasis develops acutely but the lesions are tiny, quite red, well defined papules with a white thick scale. It is distributed all over the body (not just the trunk) and follows a sore throat.
  • Seborrheic eczema: – The lesions of seborrheic eczema favour the sternum and centre of the back and are red ill defined scaly and often annular and rather chronic.
  • Para psoriasis: – There should be no difficulty here. The lesions in Para psoriasis are much larger and very slow to develop, asymmetrical and the surface of the lesions is wrinkled and atrophic.
  • Drug eruptions: – The history of ingestion of a drug should help to distinguish the two, but actually eczematous reactions to oral agents are not common although gold may sometimes simulate pityriasis rosea. The tongue is usually quite sore. The patient may be unwell and subsequently the hair and nails may be involved. A biopsy should distinguish the two and in particular eosinophils are present in drug eruptions.

Diagnosis of Pityriasis rosea

Diagnosis is based on clinical examination; 50% of patients have or recall having a “herald patch,” which is a lone, erythematous area, 2 to 10 cm in diameter, with raised, edematous borders. This lesion is usually on the trunk, but it may be located elsewhere. Between 7 and 10 days after the appearance of the herald patch, a diffuse eruption of smaller, pink, oval shaped, papulosquamous patches appears along the skin tension lines. This distribution of the lesion leads to the so called “Christmas tree” pattern on the back. They have a fine scale that may be located around the edges. The lesions can coalesce and recur.

Clinical Complications

PR can last for months, with a waxing and waning course. The course is generally benign and healing complete, although patients should be informed that post inflammatory pigmentation changes may persist. If lesions persist for longer periods or are referred for dermatologic evaluation for psoriasis Guttate and other conditions that mimic PR

Prognosis and Treatment of Pityriasis rosea

Pityriasis rosea invariably resolves within 2 weeks to 2 month. Recurrence is unusual. Most patients are managed symptomatically with such agents as low to mid potency topical corticosteroids or oral antihistamines. Ultraviolet B phototherapy also appears to shorten the disease course if initiated early.

Homeopathic treatment of pityriasis rosea – Homeopathy is one of the most popular holistic systems of medicine. The selection of remedy is based upon the theory of individualization and symptoms similarity by using holistic approach. This is the only way through which a state of complete health can be regained by removing all the sign and symptoms from which the patient is suffering. The aim of homeopathy is not only to treat pityriasis rosea but to address its underlying cause and individual susceptibility. As far as therapeutic medication is concerned, several remedies are available to cure pityriasis rosea that can be selected on the basis of cause, sensations and modalities of the complaints.  For individualized remedy selection and treatment, the patient should consult a qualified homeopathic doctor in person. There are following remedies which are helpful in the treatment of pityriasis rosea:

Arsenic Album, Calcaria Carb, Colchicum, Mercurius, Mezarium, Phosphorous, Sepia, Silicea, Sulphuric Acid, Thuja, Agaricus, Anacardium, Argentum Met, Ars Iod, Caulophyllum, Natrum Mur, kali Ars, kali Brom and many other medicines.

Reference:

Sehgal; Textbook of Clinical Dermatology; 2004; 96

Anthony Du Vivier, Phillip H. McKee; Atlas of clinical dermatology; 2002; 90

Michael l. Greenberg: Greenberg’s text atlas of emergency medicine; 2005; 411

Lippincott Williams & Wilkins: Professional Guide to Diseases; 2008; 773-774

Klaus J. Busam: Dermatopathology; 2009; 21

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Ashish Sharma

Ashish Sharma

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