Causes of urticaria

Causes of urticaria

Urticaria - hives, called "pitti" or "sheet-pitta" in many Indian households - appears when mast cells in the skin release histamine and other chemicals. The histamine makes small blood vessels leak fluid into the skin, producing the raised, itchy wheals. What sets the mast cells off varies widely.

Common triggers of acute urticaria (lasting under 6 weeks):

• Infections - the commonest trigger, especially viral fevers and throat infections; the hives often follow the infection by days
• Medicines - antibiotics (penicillins especially), painkillers of the NSAID class (ibuprofen, diclofenac, aspirin), and others
• Foods - nuts, shellfish, eggs, milk, certain fruits, and food additives; true food-triggered hives appear within minutes to two hours of eating
• Insect stings and bites

Physical urticarias (a distinct group): hives triggered by physical stimuli - pressure (tight straps, sitting), scratching (dermographism - writing on the skin), cold, heat, sunlight, sweating/exercise (cholinergic), and water (rare). Each has its own pattern and its own avoidance strategy.

Chronic urticaria (over 6 weeks) - the honest truth: in the large majority of chronic cases, no external cause is ever found. This is not a failure of testing but the nature of the disease: chronic spontaneous urticaria is often autoimmune - the body's own antibodies activate the mast cells. It is not an allergy, not "impure blood", and not caused by eating something wrong for years. Knowing this saves patients from years of unnecessary food bans and expensive allergy panels.

Associated conditions worth checking in chronic cases: thyroid disease (especially autoimmune thyroiditis), and occasionally other autoimmune conditions.

Remember: acute hives usually trace to infection, medicines or food; chronic hives are usually the immune system misfiring on its own. Lip, tongue or throat swelling with hives is a different, dangerous event - emergency care, always.

Ayurvedic view (interpretive)

Ayurveda's Sheetapitta/Udarda describes wind-and-cold-linked itchy wheals - a descriptive parallel. The histamine mechanism and the autoimmune nature of chronic cases are modern findings that guide real treatment.