Role of streptococcal infection in the etiopathogenesis of pityriasis lichenoides chronica and the therapeutic efficacy of azithromycin: a randomized controlled trial

The exact aetiology of pityriasis lichenoides chronica (PLC) remains unknown. While phototherapy is the most investigated therapeutic modality, azithromycin has been used scarcely. The aim of this study is to evaluate the therapeutic efficacy of azithromycin in the treatment of PLC compared to NB-UVB and evaluating the presence of streptococcal infection as a possible etiological factor in PLC patients. The study was designed as a randomised controlled trial. Twenty-four patients with PLC were randomly allocated into either azithromycin (n = 13, standard dose every 10 days) or NB-UVB (n = 11, thrice weekly) groups. End of study (EOS) was either complete clearance of lesions or a maximum of 8 weeks. Therapeutic efficacy was defined as percent reduction in lesions and was calculated for the rash as a whole, erythematous papules alone, and hypopigmented lesions alone and graded into complete, very-good, good, poor or no response. Anti-streptolysin O titre (ASOT), anti-deoxyribonuclease B titre (anti-DNaseB) and throat culture were evaluated at day 0. No significant difference existed between both groups as regards therapeutic efficacy. At EOS, NB-UVB achieved significantly more percent reduction in the extent of hypopigmented lesions and consequently in the rash as a whole (p = 0.001, p = 0.034, respectively). The extent of the rash as a whole was significantly less in the NB-UVB at EOS (p = 0.029, respectively). The effect of NB-UVB on hypopigmented lesions appeared early at week 4 of treatment. Only two patients, one from each group, relapsed during the 3 month follow-up. Evidence of recent streptococcal infection was present in 79% of the cases, mainly in the form of elevated ASOT (94.7%). It was significantly more encountered in young children (< 13 years) (p = 0.03) and was associated with more extent of erythematous papules and consequently with more extent of the rash as a whole (p = 0.05 and p = 0.01, respectively). It did not affect outcome of therapy at EOS. Azithromycin did not show more favorable response in patients with recent streptococcal infection. Therapeutic efficacy of azithromycin is comparable to NB-UVB in treatment of PLC; however, NB-UVB is superior in management of hypopigmented lesions. It is highly suggested that PLC could be a post streptococcal immune mediated disorder.Registration number: ClinicalTrials.gov, NCT03831269.

Poikilodermatous Mycosis Fungoides: Comparative Study of Clinical, Histopathological and Immunohistochemical Features

BACKGROUND

Poikilodermatous mycosis fungoides (pMF) is characterized by poikiloderma areas, typically involving the major flexural areas and trunk. Its presentation can be generalized or admixed with other forms of MF. Previous studies fail to correlate the clinical presentation with prognosis and laboratory findings. Some reports show pityriasis lichenoides chronica (PLC) preceding the poikiloderma.

OBJECTIVES

Correlate prognostic, histopathological and molecular aspects of pMF with its clinical presentation.

METHODS

Retrospective analysis of 14 cases of generalized pMF (GpMF), 22 of localized pMF (LpMF) and 17 of pMF admixed with other forms of MF (mix-pMF).

RESULTS

Female predominance and lower age at diagnosis was found in all groups compared to classic MF, a high prevalence of PLC-like lesions in the GpMF group and a high rate of hypopigmented lesions in the mix-pMF group. There were 2 deaths within the GpMF group. Histology was similar to previously reported findings, as was the prevalence of CD4 T-cell infiltrate, compared to CD8. The T-cell clonality positivity was lower in the GpMF group, compared to other groups (27% GpMF, 80% LpMF and 100% mix-pMF).

DISCUSSION

This is the first article to categorize the different forms of pMF and correlate them with clinical and laboratory findings. The dermatological presentation differs among the groups. There was a high frequency of PLC-like lesions within the GpMF group and of hypopigmented lesions in mix-pMF. The histological and immunohistochemical findings were similar to those previously reported. Aggressive treatments are not recommended due to the good prognosis of all pMF forms. The low positivity of T-cell clonality in the GpMF group should be investigated.

The Effectiveness of Narrow Band Uvb (Nb-Uvb) In the Treatment of Pityriasis Lichenoides Chronica (PLC) In Vietnam

AIM

This prospective clinical study presents the experiences with NB-UVB monotherapy in the treatment of PLC on Vietnamese patients.

METHODS

We enrolled at National Hospital of Dermatology and Venereology (NHDV), Vietnam, 29 PLC patients with generalised disease involving at least 60% of the total body surface (based on Nine's Rule) and/or failed to respond to other modalities of treatment. Patients were treated with NB-UVB followed the guideline of the psoriatic treatment of AAD-2010, three times weekly.

RESULTS

A complete response (CR) was seen in 24 out of 29 PLC patients (82.8%) with a mean cumulative dose of 9760.5 mJ/cm² after a mean treatment period of 4.6 weeks (13.8 ± 7.4 exposures). Mild side effects were observed: 69% erythema minimum, 55.2% irritation related to dry skin. No severe side effects were seen during the study. No relapses occurred in 24 CR patients within a mean period of 3 months after the last treatment.

CONCLUSION

NB-UVB therapy is an effective and safe option for the treatment and management of PLC.