Question

My 5-month-old son has had red bumps on the soles of his feet for at least four weeks now. We have run the gamut with the doctor's diagnoses. First we thought it was hand, foot, and mouth disease, but that was ruled out due to lack of fever and duration. The next diagnosis was infant acne, and just one week ago we were thinking it might be an allergic reaction to his socks (the rubber nonskid ones). As the bumps dry out, they tend to peel and go away, but more keep returning. Is there anything we might be missing? The bumps appear to make him itch, and at times his entire foot is bright red. Under advice, he has not worn socks since the last diagnosis, but with winter here, I would really like to know how to clear up his condition.

Answer

It is unclear from your description whether these bumps are deep in the skin or superficial and whether they are associated with any other changes, such as scaling, pustules ("whiteheads"), or scabbing.

Multiple disorders can cause bumps on the soles of an infant's feet, including infections, scabies, urticaria (hives), eczema, and psoriasis. Some rare disorders that could trigger these bumps include histiocytosis, erythema nodosum, and palmoplantar hidradenitis. Lastly, there is a condition called infantile acropustulosis that produces recurrent crops of very itchy red bumps, many with pus. They occur most commonly over the soles of the feet and the ankles and occasionally over the palms of the hands, the wrists, or the scalp. The bumps occur in a cyclical fashion every two to four weeks and go away in one to two weeks with peeling before flaring up again.

An allergic reaction to the socks would be very unlikely, and infant acne does not occur on the soles, as there are no hair follicles there. Have your son evaluated by a dermatologist, who will be able to give you a diagnosis and offer suggestions for therapy.