10% Thioglycolic Acid Peel in the Treatment of Pigmented Purpuric Dermatoses: A Pilot Study

Pigmentary purpuric dermatosis (PPD) is a chronic dyspigmentation characterized by reddish-brown, irregular maculae with dermal hemosiderin deposition, usually affecting the legs. The -SH group in the thioglycolic acid (TGA) strongly binds to iron molecule, solubilizes it, and clears the pigment. We conducted a longitudinal, right-left leg study for assessing the effectiveness and side effects of TGA 10% peel in treating PPD. For preparation of 10% TGA peel, 80% TGA was diluted with distilled water to 10% concentration by mixing 0.5 mL of acid with 3.5 mL of water before every peel session. The peel was applied on the left leg, weekly for 6 weeks. Assessment was done at baseline and at weeks 3 and 6. Any improvement was noted by the patient and another independent dermatologist. The right leg was untreated. Any side effects during peel application and afterwards were noted. According to the patient assessment, 4/10 patients observed mild improvement, 5/10 patients had moderate improvement, and only a single patient had marked improvement. In the physician assessment, 2/10 patients had >50% improvement, 5/10 patients had 30-40% improvement, and 3/10 patients had 10-20% improvement. Side effects included slight burning during application and foul odor. A single patient had intense erythema and mild swelling of the leg after peel application. 10% TGA is effective in the partial clearance of PPD dyspigmentation with weekly sessions for 6 weeks without any serious side effects.