Hello, Welcome to Healthcare Magic. I have read your question fully and understand your concerns. I do not think that the rash has any relation with your thyroid problem. From you are describing (especially about the description of chicken skin like rash), I think you are having Keratosis pilaris. It is a common persistent harmless condition, where there are small red or white bumps on the skin. This occurs when there is too much keratin in the skin. Keratin is a protein found in the strong outer layer of the skin. This keratin can then block the hair follicle pores and the pores widen giving the appearance of raised bumps. This is associated with eczema sometimes. Keratosis pilaris sometimes run in families. Is any other family member having the same? Treatment is by avoiding soap (use soap substitutes instead like Oilatum bath additive), gentle exfoliation of the rough skin, moisturisers etc. Exfoliating peels, creams containing retinol are also used. It is best to see a dermatologist for proper diagnosis and management. I hope this answer has helped you. Thank you Regards Dr Sunita Sayammagaru