Redness, Itchiness under the breasts over ribcage
A red 'sweat rash' develops under the breasts. It may be sore and itchy, and you may have it in armpits as well. The rash has a definite edge, and there may be some whitish material on it. It is usually caused by fungus or bacteria, which likes to live in warm, moist places. If you are overweight as well as having large breasts, the skin crease underneath them is ideal. Skin that has been slightly damaged makes it easier for the fungus to take hold.
Get a supportive bra to lift your breasts up. Although underwired styles give good support, they tend to trap sweat under the breasts so choose a non-wired style. Cotton is better than a synthetic fibre because it allows sweat to evaporate. Wash it in a non-biological (non-enzyme) detergent and don't use a perfumed fabric conditioner.
Wash carefully under the breasts with a non-perfumed soap, as some perfumes can damage the skin. Don't put any disinfectants in the water. Rinse well to ensure no lather remains in the skin crease. Dry thoroughly but gently – pat dry with a soft towel or use a hairdryer. Don't wash your hair with shampoo in the shower – the shampoo may contain perfume that trickles down and irritates the area under your breasts.
Stop applying creams. If you have been applying creams from the chemist, stop using them, even if they are for fungus. You could have become sensitized to one of the ingredients, and the cream could be making it worse. Instead, simply follow the instructions above for 2 weeks. If at the end of that time the rash is no better, see your doctor who will be able to prescribe a different cream.Lose weight, if you need to. If you are obese, you may find the rash difficult to eliminate completely unless you lose some weight.