Hi Suzanne, Sounds like low potassium and/or low methylfolate. Headaches go both ways. Itching, specifically subdermal is often low potassium. With a rash it is usually low methylfolate. Version 1.2 12/08/2013 Group 1 – Hypokalemia onset. Symptoms may appear with serum potassium as high as 4.3. May become dangerous if ignored. Considered “rare” with CyCbl (cyanocobalamin) it is very common with MeCbl (methylcobalamin) and AdoCbl (adenosylcobalamin) and less so with HyCbl (Hydroxycobalamin). There does not appear to be a clear order of onset. The order of onset varies widely from person to person but many appear consistent for each episode for any given person. There tend to be more and more intense symptoms as it gets worse. Some people have ended up in the ER because of not recognizing the symptoms. IBS – Steady constipation, Nausea, Vomiting, Paralyzed Ileum, Hard knots of muscle, Sudden muscle spasms when relaxed, Sudden muscle spasms when stretching , Sudden muscle spasms when kneeling, Sudden muscle spasms when reaching , Sudden muscle spasms when turning upper body to side, Tightening of muscles, spasms and excruciating pain in neck muscles, waking up screaming in pain from muscle spasms in legs. Muscle weakness Abnormal heart rhythms (dysrhythmias), increased pulse rate, increased blood pressure Emotional changes and/or instability, dermal or sub-dermal Itching, and if not treated potentially paralysis and death. Group 2a - Both IBS – Diarrhea alternating with constipation, IBS – Normal alternating with constipation Group 2b – Either or both Headache, Increased malaise, Fatigue Group 3 - Induced and/or Paradoxical Folate deficiency or insufficiency These symptoms appear in 2 forms generally, the milder symptoms that start with partial methylation block and the more severe symptoms that come on as partial methylation block gets worse or very quickly with methyltrap onset. Edema - An additional thing I would like to mention. I would never have found it without 5 years of watching the onset of paradoxical folate insufficiency and trying to catch it earlier and earlier and to figure out what was causing it and to reverse it. For me the onset order goes back to the day of onset now with edema and a sudden increase of weight. I noticed that within 2 hours of taking sufficient Metafolin I would have an increase in urine output. Old symptoms returning Edema Angular Cheilitis, Canker sores, Skin rashes, increased acne, Skin peeling around fingernails, Skin cracking and peeling at fingertips, Increased hypersensitive responses, Runny nose, Increased allergies, Increased Multiple Chemical Sensitivities, Increased asthma, rapidly increasing Generalized inflammation in body, Increased Inflammation pain in muscles, Increased Inflammation pain in joints, Achy muscles, Flu like symptoms IBS – Steady diarrhea, IBS – Diarrhea alternating with normal, Stomach ache, Uneasy digestive tract, Coated tongue, Depression, Less sociable, Impaired planning and logic, Brain fog, Low energy, Light headedness, Sluggishness, Increase irritability, Heart palpitations, Longer term, very serious Loss of reflexes, Fevers, Forgetfulness, Confusion, Difficulty walking, Behavioral disorders, Dementia, Reduced sense of taste, bleeding easily Group 4 - HyCbl onset, degraded MeCbl onset, MeCbl after photolytic breakdown onset. Itchy bumps generally on scalp or face that develops to acne like lesions in a few days from start. It took me 10 minutes after putting the first MeCbl under my tongue to start feeling better.