Maybe that is what starts intertrigo, but the warmth, moisture and debris in skin folds provide ideal conditions for bacteria or yeasts.
This happens in armpits, groins and under abdominal "aprons" and breasts.
(When people get straight mechanical chafing, it is usually between their upper thighs, not right in the skin crease.)
This is usually a red rash, spreading out from the crease of the skin fold. When Candidiasis is involved, there are usually little red spots beyond the confluent red area.
The problem is more often a bad odour rather than pain.
Frequent washing with just plain water, avoiding soap or soap substitutes, is essential.
Dry thoroughly and apply a lotion made from equal parts of colloidal silver and sorbolene cream. This is very effective for combatting any infection.
Hypericum ointment is also very effective.
This is dry and may be brownish rather than red.
For pictures see the dermnetnz site.
Psoriasis on the points of elbows or knees usually has thick silvery scaling on the surface.
In flexures, it hasn't this scaling, and is just a red rash with a sharp margin.
In flexures it can look somewhat similar.
The common flexural atopic eczema is usually behind knees and in front of elbows and ankles, wrists.
It can occur in the bigger skin folds as well, however.
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