Background: Palmoplantar psoriasis (PPP) is a disabling condition which is usually resistant to most of the available therapeutic modalities. Coal tar is an accepted therapy for psoriasis which has not been well studied for PPP.
Methods: Thirty patients with a plaque type of PPP were allocated into two groups: Group A (19 patients) were treated with 6% crude coal tar (CCT) ointment and Group B (11 patients) were treated with white petrolatum and salicylic acid. In both groups, ointment was applied and left on overnight. Wearing of gloves and socks during the night and application of emollients in the day was routinely advised. The lesions were assessed for erythema, scaling, and induration (ESI) every 2 weeks for a total of 8 weeks. Patients with greater than 50% improvement were considered to have good improvement. Side-effects, if any, were also monitored.
Results: In Group A, 76.5% of patients (13/17) showed good improvement, whereas only 45.5% of patients (5/11) in Group B showed the same magnitude of improvement (P < 0.05). No side-effects were reported by any patient in either of the groups.
Conclusions: Crude coal tar is a safe, effective, and inexpensive modality for the treatment of PPP. We recommend coal tar under occlusion, along with the liberal use of emollients, as the first line of therapy for all cases of PPP.