Hello! I think I might know what you have, because it sounds like what I've been diagnosed with. (* I'm no doctor, no medical back ground) it took them many tests and six months to finally find out. I have a rare form of Tinea Capitas, (* adult scalp large ringworm. (* Not to be confused with regular ringworm. The kind i have can become really serious) the regular scalp Fungus can be diagnosis with a culture. The rare form, that infects the INSIDE of the hair shaft, will show negative on the culture. It also doesn't have much rash or lesions. You need a special test to diagnose it. Infected hairs need to be examined by direct microscopic under 400 magnification with KOH solution. There lab is looking for Hyphae. To find infected hairs, go to itchy spot and pluck hairs. With a bright flashlight and magnifying glass, look for dots INSIDE the hair shaft, or barcode-like appearance. Also, look for tiny lint-appearing thingys on the hair. If you have this, you need oral antifungal meds ASAP, as well as topical. You won't notice a difference for a few weeks, so be patient. ALSO, research disinfectecting your environment, especially your bed linens, washer and dryer, car, clothes, pay close attention to towels. Contact with the hair, and dampness makes the fungus grow like crazy. Research natural antifungal remedies, for both inside and outside of the body. Don't give up! This CAN be beaten!
I had itchy skin from B12 deficiency but it was all over my body. My B12 deficiency was due to autoimmune pernicious anaemia. Most cases of B12 deficiency are due to malabsorption from low stomach acid to celiac disease. You want to find out why your B12 was so low. I have read an itchy scalp can be a symptom of celiac disease for instance. You may even need to try an elimination diet to rule out any food sensitivities. I had an insanely itch scalp for a month due to sugar withdrawal so I know how you feel. A very long month!
From B12 awareness - Causes of B12 deficiency:
"Decreased stomach acid
Autoimmune pernicious anemia
Gastrectomy, intestinal resection
Gastric bypass surgery
Celiac disease (gluten enteropathy)
Bacterial overgrowth (small bowel)
Advanced liver disease
Transcobalamin II deficiency
Inborn errors of B12 metabolism