Efficacy of botulinum toxin for a congenital eccrine naevus.

Editor Congenital eccrine naevus is a rare clinical entity. Fewer than 20 cases had been reported, and only three cases were congenital. 1,2 We present a child with congenital localized hyperhidrosis on the forearm. To the best of our knowledge, this is the first congenital eccrine naevus successfully treated with botulinum toxin type A. A 12-year-old girl with no significant past medical history presented with a history of localized excessive sweating on the right forearm from birth. The episodes were twice a week and were initially confused by their parents with enuresis. At 6 years of age, the episodes began more frequently, compromising her school activities. The episodes occurred daily, were preceded by a paresthesic sensation on the area and were precipitated by heat, physical activity and specially by the muscular strain of handwriting. Physical and neurological examinations were normal. Epidermic changes were not observed in the hyperhidrotic area. A provocation test with exposition to heat for 30 min confirmed a hyperhidrotic area of 5 × 4 cm localized on the ulnar emminence of the right wrist. Sweat dripped from the area (fig. 1). An incisional biopsy specimen showed a proliferation of eccrine glands of the deep dermis and hypodermis (fig. 2). Topical treatment with aluminium chloride 20% was unsuccessful. Surgical extirpation was discarded due to the size of the lesion. Considering the interference with her school activities and according to her mother's previous consent, treatment with botulinum toxin type A (Botox Allergan, USA) was performed. Botulinum toxin type A was diluted in 4 mL of saline solution 0.9%, with 5 U per intradermic injection, at intervals of 0.5 to 1 cm. Up to date, 1 year after, a significant decrease of sweat episodes to once a month, and an improvement in our patient's quality of life was achieved. This case is the first congenital eccrine naevus successfully treated with botulinum toxin, according to our literature revision. Eccrine naevus (EN) is a hamarthome characterized histologically by increased number and/or size of the eccrine glands, without vascular proliferation. It should be differentiated from eccrine angiomatose hamarthome and from sudoriparous angiome. Eccrine angiomatose hamarthome is a frequent pathology that presents a vascular proliferation associated with hyperplasia of the sudoriparous glands. 3 Hypertrophy of the eccrine glandular component with vascular proliferation is named sudoriparous angiome. In this case, the absence of vascular proliferation, confirmed the diagnosis of a pure eccrine naevus, with fewer …