To investigate the hidrotic condition and sweat recovery after corticosteroid pulse therapy, we performed hyperthermia sweating test, acetylcholine dermal injection test, and histopathological examinations on seven patients with acquired idiopathic generalized anhidrosis (AIGA)/anhidrotic or hypohidrotic cholinergic urticaria. All the patients were male, and decreased sweating was found on the more than 80% of their body surfaces. Six of 7 patients had cholinergic urticaria. The predilection sites of anhidrosis were mainly the lower extremities, while the hypohidrotic areas included the upper limbs and trunk. After treatment with corticosteroid pulse therapy, sweating recovery was observed in all patients, and cholinergic urticaria appeared in the sweating recovery sites. Our study showed that cholinergic urticaria appears in the hypohidrotic sites but not in the anhidrotic areas.
A 63-year-old man presented with 2-month history of pruritus and tense bullae on almost his entire body. He had been treated for type 2 diabetes mellitus with oral antidiabetic medications, including vildagliptin, which is a kind of dipeptidyl peptidase-4 (DPP-4) inhibitors. Clinical and histopathological findings and indirect immunofluorescence analysis were compatible with bullous pemphigoid (BP). Results of a test using BP180NC16a-CLEIA and BP230-ELISA of the patient's serum were negative. Immunoblotting of a full-length BP180 recombinant protein was positive. The patient discontinued the vildagliptin and started taking minocycline and nicotinamide with topical betamethasone butyrate propionate. He had no active lesions after two weeks. After he stopped taking the minocycline and nicotinamide, the BP did not recur. We diagnosed the case as bullous pemphigoid induced by vildagliptin. Sixteen cases, including ours, of bullous pemphigoid induced by DPP-4 inhibitor have been reported. Most of these cases improved after withdrawal of DPP-4 inhibitor without systemic corticosteroid therapy. As DPP-4 inhibitors are widely used for the treatment of diabetes mellitus, we toned to be aware of the possible adverse effect.