This does seem to be an allergic rash. They usually appear suddenly and will keep spreading until the offending agent is removed from the body.
The pathological reaction that takes place on your skin due to foreign particles is considered as allergy rash. This is a misdirected immune response of the body which causes the release of histamine.
This allergy rash can be identified itchy and swollen red bumps or patches all over the body.
Food, medications, cosmetics, insect bites, pollen and other plants and sun exposure are common causes. You can apply Calamine lotion on the bumps and take anti-histamines like Cetrizine for it.
Viral infections can sometimes cause a non-specific dermatitis which can present as allergic rash but may not be itchy. It is self-limiting and will resolve in 7-10 days without treatment.
It could be eczema, sweat dermatitis, allergic reactions or herpes.
You need to wash the areas several times with fresh water. Do not use any cosmetic products at the sites.
Apply calamine lotion at the site of the lesions and see if it helps. You could take some oral antihistamine medications like cetrizine or loratadine. You need to maintain a good personal hygiene . Use a medicated sunscreen and avoid sun exposure.
Anti-itch drugs, often antihistamine, may reduce the itch during a flare up of eczema, and the reduced scratching in turn reduces damage and irritation to the skin.
For mild-moderate eczema a weak steroid may be used (e.g. hydrocortisone or desonide), whilst more severe cases require a higher-potency steroid (e.g. clobetasol propionate, fluocinonide).
Eczema can be exacerbated by dryness of the skin. Moisturizing is one of the most important self-care treatments for sufferers of eczema. Keeping the affected area moistened can promote skin healing and relief of symptoms.
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It would be advisable to consult a skin specialist for your symptoms and a proper clinical examination.
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