Hi, You said you have rash on extremities with stinging sensation. Most probably the rash you desribed might be miliaria...as there is stinging sensation. There may be reddish microvesicular rash. Other possibility is prurigo...as the the lesions are relapsing. It is difficult to pinpoint exact diagnosis with this little history. You personally consult dermatologist. Blood tests may be done to rule out internal diseases. You might get relief after taking antihistaminics like desloratidine. Soothing lotion of calamine with alovera might improve the disease. If needed, steroid in tappering doses may be taken. You might feel better in few weeks. I hope you got my answer. Thanks. Dr. Ilyas Patel MD