Treatment of acute guttate psoriasis with rifampicin

Introduction

Aetiology of psoriasis is not exactly known and some predisposing and exacerbating factors have been postulated. Among the precipitating factors, drugs, stress, trauma and infection have been seen responsible. The role of infection in precipitating psoriasis is well known. Throat infec-tion provoking acute guttate psoriasis has long been recognised. Past and more recent evidence had suggested that continuing subclinical streptococ-cal infection might also be responsible for refractory chronic plaque psoriasis. Frequency of streptococcal infection as a triggering factor for provoking psoriasis varies from as low as 15% to as high as 76%.

It is now generally accepted that strepto-coccal infection is the major precipitating factor in guttate psoriasis, but how streptococcal infection causes psoriasis is still under debate. However a recent study with streptococcal monoclonal antibodies has shown its binding to components of the keratinocytes. Thus if there is cross- reactivity between streptococcal antigens and keratinocyte components, this could explain the initiation of a disease process.

Various therapeutic modalities have been tried to eradicate the streptococcal focus from the throat for psoriasis. Allan Nytors et al followed up the course of psoriasis after tonsillectomy. He used charts and questionaires in 74 psoriatic patients. These patients were refractory to topical and peni-cillin therapy. A statistically significant clearing of the lesions was noted. William Rosenberg, studied the effect of use of rifampicin with penicillin and erythromycin in the treatment of 9 psoriasis patients with streptococcal infection who showed a marked improvement after the therapy.

A study also was carried out by us in treating patients with different forms of psoriasis with oral penicillin and the results were excellent in acute guttate psoriasis. Rifampicin is known to eradicate the streptococcal carrier state in the throat hence the present study was done.

Materials and Methods

Sixty randomly selected patients of acute guttate psoriasis of different age groups (both males and females) were taken for the study. In all the patients a detailed history including family history of the disease and history of any recent throat infection was taken. After a detailed systemic ex-amination all were subjected to throat culture and antistreptolysin 0 titer estimation. Patients were asked not to take any other drug.

All patients were put on oral rifampicin in a dose of 25mg/kg/body weight and were asked to take the drug on an empty stomach in the morning. A mild emollient was given locally in a few patients. All patients were observed for a period of 10-15 days, for clearing of lesions.

The protocol for improvement was categorized un-der three groups:-

Group-I. complete improvement when all lesions cleared.

Group-II- partial improvement when there was mild thinning of the lesions and decreased scaling.

Group-III. No improvement, when no lesions cleared during the study period. No patient was taken as control.

Results

Of the 60 patients put on rifampicin therapy 26 showed complete clearing of the lesions, while in 10 patients partial improvement was noted. No clinical improvement was noted in 12 patients and the rest of the 12 patients did not report for follow up.

Discussion

Aetiology of psoriasis is not exactly known and some predisposing and exacerbating factors have been postulated. The role of infection in pre-cipitating psoriasis is well known. Throat infection provoking acute guttate psoriasis has long been recognised. Past and more recent evidence has suggested that the continuing subclinical strepto-coccal infection might also be responsible for re-fractory chronic plaque psoriasis. ^[1] Frequency of streptococcal infection as a triggering factor for provoking psoriasis varies from as low as 15% to as high as 76%. ^[2]

It is now generally accepted that strepto-coccal infection is the major precipitating factor in guttate psoriasis, but how streptococcal infection causes psoriasis is still under debate. However a recent study with streptococcal monoclonal antibodies has shown its binding to components of the keratinocytes. Thus if there is cross-reactivity between streptococcal antigens and keratinocyte components, this could explain the initiation of a disease process. There is accumulating evidence from other disorders that infection may precipitate disease in genetically predisposed individuals giving rise to a self precipitating autoimmune state. It is possible that a similar situation exists in psoriasis. ^[3]

Various therapeutic modalities have been tried to eradicate the streptococcal focus from the throat for psoriasis. Nytors et al. ^[4] followed up the course of psoriasis after tonsillectomy. He used charts and questionnaires in 74 psoriatic patients. These patients were refractory to topical and penicillin therapy. A statistically significant clearing of the le-sions was noted.

Rosenberg et al ^[5] have studied the effect of the use of rifampicin with pencillin and erythromycin in the treatment of 9 psoriasis patients with streptococcal infection who showed a marked improvement after the therapy.

Vincent et al ^[6] have studied 20 patients who were divided into two groups. One group was given pencillin or erythromycin for 14 days with a placebo added during the last 5 of the 14 days. The other group received the same medication with the addition of rifampicin in the last five days. However the results were not encouraging.

A study was carried by us ^[7] also, treating patients with different forms of psoriasis with oral pencillin and the results were excellent in acute guttate psoriasis.

In the present study, only patients with acute guttate psoriasis were taken and they were given oral rifampicin, keeping in view the definite possible factor in the form of streptococcal infec-tion in the throat for initiation of the pathological state. Rifampicin is thought to eradicate the streptococcal carrier state in the throat.

Kashmir is a cold state and psoriasis is common here, especially during winter seasons when streptococcal infections are at their peak. ^[8] By treating patients by Rifampicin, disease precipitation can be reduced.

Out of 60 patients with acute guttate pso-riasis, 26 showed complete improvement while 10 showed only partial improvement. Though our study was an uncontrolled one the results were encouraging indicating that patients of acute guttate psoriasis having streptococcal infections as a precipitating factor can be helped as far as disease provocation is concerned, if treated properly with rifampicin. Further studies are needed to confirm the role of rifampicin in the treatment of psoriasis.