A Phase 1, Open-label, Multicenter, Safety and Pharmacokinetic Study of EDI200

Inclusion Criteria: 1. Males and females of child-bearing age, age 18-40 years 2. Weight between 45 and 90 kg and a body mass index (BMI) from 18 to 29 kg/m2 (calculated using the following formula: weight in kilograms/(height in meters)2) 3. Both males and females must be documented (via genetic testing) to carry an EDA mutation associated with XLHED; or have the clinical signs and symptoms associated with HED and/or a family history of HED and provide a blood sample to be sent for genetic testing that confirms an EDA mutation associated with XLHED 4. No major medical issues that the investigator considers to be a contraindication of participation 5. No scalp shaving in the month prior to first dose (males only) 6. Women must use a "highly effective" method of contraception throughout the trial. Highly effective methods of birth control are defined as those, alone or in combination, which result in a low failure rate (i.e. less than 1% per year) when used consistently and correctly. These methods include implants, injectables, oral contraceptives, some intrauterine contraceptive devices, sexual abstinence, tubal ligation or a vasectomized partner. 7. No treatment with an investigational drug within the last three months 8. Signed written informed consent Exclusion Criteria: 1. Women who are pregnant (confirmed via urine pregnancy test) or breastfeeding at screening or planning to become pregnant at any time during the study period 2. Known history of hepatitis B surface antigen (HBsAg) or hepatitis C (HCV) antibody 3. Known history of HIV infection 4. Known hypersensitivity to pilocarpine or pilocarpine-like muscarinic agonists 5. Known hypersensitivity to lidocaine or lidocaine-like agents 6. Presence of pacemakers 7. Subjects who are not able or are not willing to comply with the procedures of this protocol 8. Subject has a condition which in the opinion of the investigator would not allow for safe conduct of the study