A study at Department of Dermatology and STD, Jawaharlal Institute of Postgraduate Medical Education and Research, India suggests that there is no association between streptococcus pharyngitis and pityriasis rosea.
Pityriasis rosea is self limited skin condition of uncertain etiology. The exact cause of pityriasis rosea is not known but various hypotheses have been postulated incriminating infective agents such as viruses, bacteria, spirochete and noninfective etiologies such as atopy and autoimmune causes have also been investigated.
They undertook a study to investigate the role of Streptococcus haemolyticus in the causation of pityriasis rosea and study the levels of C-reactive protein (CRP) and ASLO titer in patients with pityriasis rosea.
The study included 20 patients with pityriasis rosea attending the outpatient dermatology department at JIPMER hospital during the period from June to December 2004. Corresponding number of age- and sex-matched controls were chosen from amongst healthy individuals and patients attending skin OPD with dermatological disorders other than pityriasis rosea.
On analyzing the data collected from 20 cases of pityriasis rosea, the average age was found to be 15.3 years and ranged from 5 years to 30 years. The male to female ratio was found to be 1.5:1. The average duration of illness was 14.5 days (median) and 29.3 days (mean). CRP was negative in all the cases as well as the controls. ASLO titer was found to be raised in 2 (10%) cases, while it remained below the critical value in all the controls. On comparing the cases and controls, the raised ASLO titer in the cases was found to be not statistically significant (p = 0.147). From the throat swab culture, Streptococcus haemolyticus was isolated from only one case and none of the controls. This finding was not statistically significant (p = 0.310).
As per the findings of the present study, They arrived at conclusion that there is no association between streptococcus pharyngitis and pityriasis rosea.
Parija M, Thappa DM. Study of role of streptococcal throat infection in pityriasis rosea. Indian J Dermatol [serial online] 2008 [cited 2009 Jan 3];53:171-3. Available from: http://www.e-ijd.org/text.asp?2008/53/4/171/44787