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A 30-year-old member asked:

Itchy bumps for a week now after going biking w/ sunscreen. seem to be clear/flesh colored until i scratch them and they turn red. is it heat rash?

49 doctor answers20 doctors weighed in
Dr. Gerry Tolbert
Family Medicine 13 years experience
Maybe: "heat rash" is a pretty non-specific term. The fact that the bumps have lasted a week or so means it's probably something a little more significant. The rash could be allergic in nature, whether to the sunscreen or something environmental. A trial of topical steroid cream, like hydrocortisone, may help, but if it doesn't improve in the next few days, i'd have it checked by your doctor.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Possibly, : A heat rash is a definite possibility, but contact allergy associated with your sunscreen or topical creams placed may do the same thing. Recommend stop scratching them. Scratching them will further the insult, and the redness is from the dilation of skin vessels (therefore, red). Unroofing them may cause problems. Ok to try 1% hydrocort creams. See physician if not cleared in a week.
Dr. Otto Placik
Plastic Surgery 34 years experience
Allergy vs drug RN: This could be due to any number of things including heat rash. I would also be concerned about a possible allergy or sensitivity to one of the ingredients in the sunblock.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Otto Placik
Plastic Surgery 34 years experience
Rash or drug rxn?: There are a variety of possible causes for this including photosensitivity induced by systemic drugs such as bactria, contact dermatitis due to a reaction to the sunscreen or, yes, heat rash. In the latter case it will likely be limited and short lived. In the former, you should determine the cause. In the meantime consider topical Benadryl (diphenhydramine) and Hydrocortisone for short term relief.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Renee Burke
Plastic Surgery 19 years experience
Depends: Difficult to tell, you should follow up with your dermatologist or primary care physician.
Dr. Gerry Tolbert
Family Medicine 13 years experience
Maybe: "heat rash" is a pretty non-specific term. The fact that the bumps have lasted a week or so means it's probably something a little more significant. The rash could be allergic in nature, whether to the sunscreen or something environmental. A trial of topical steroid cream, like hydrocortisone, may help, but if it doesn't improve in the next few days, i'd have it checked by your doctor.
Dr. Frederick Coville
Plastic Surgery 39 years experience
Not sure where?: I'm not sure where your rash is and so it is almost impossible to give you an answer. Yes it it possibly a heat rash. But after a week, that should have gotten better. Please see your family doctor or dermatologist. Be well, .
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Richard Tholen
Plastic Surgery 41 years experience
Need personal exam!: Even though you have provided a description, actual examination of your rash is needed to provide a meaningful diagnosis. See a dermatologist if this persists or worsens.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Otto Placik
Plastic Surgery 34 years experience
Heat or allergy?: This may be an allergic reaction as well to the sunscrren.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Otto Placik
Plastic Surgery 34 years experience
Heat, drugs, etc: There are a variety of possible causes for this including photosensitivity induced by systemic drugs such as bactria, contact dermatitis due to a reaction to the sunscreen or, yes, heat rash. In the latter case it will likely be limited and short lived. In the former, you should determine the cause. In the meantime consider topical Benadryl (diphenhydramine) and Hydrocortisone for short term relief.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Frederick Coville
Plastic Surgery 39 years experience
Impossible to say: I am sorry but it really is impossible to say what your rash is caused by without seeing it. Heat rash should have resolved by now. Please see a good dermatologist or your family doctor. Be well.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Richard Tholen
Plastic Surgery 41 years experience
Personal exam needed: Even though you have provided a description, actual examination of your rash is needed to provide a meaningful diagnosis. See a dermatologist if this persists or worsens.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. James Beckman
Plastic Surgery 51 years experience
Not likely: It is likely the sunscreen had an ingredient that when exposed to sun caused a reaction called "photo sensitivity".
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Frederick Coville
Plastic Surgery 39 years experience
Impossible to say: I am sorry but it really is impossible to say what your rash is caused by without seeing it. Heat rash should have resolved by now. Please see a good dermatologist or your family doctor. Be well.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Carmen Kavali
Plastic Surgery 25 years experience
More info needed: Where are these bumps? Are they where you applied sunscreen? Or under your clothing? Does anything make them better? Anything make them worse?
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Frederick Coville
Plastic Surgery 39 years experience
Not sure where?: I'm not sure where your rash is and so it is almost impossible to give you an answer. Yes it it possibly a heat rash. But after a week, that should have gotten better. Please see your family doctor or dermatologist. Be well, .
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Otto Placik
Plastic Surgery 34 years experience
Allergy vs rash: This could be contact dermatitis to one of the ingredients in the sunscreen as well. Topical Benadryl (diphenhydramine) and 1% Hydrocortisone screen may also be beneficial to alleviate symptoms. Heat rash is also a possibility and will likely be short lived and limited to the sunexposed areas only.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Lavinia Chong
Plastic Surgery 33 years experience
Contact dermatitis: Itchy, raised bumps, after exposure to a novel sunscreen is probably contact dermatitis, a form of allergy. Scratching releases histamine and if excessive can result in bacterial superinfection. Treat your skin gently, with soap and water, avoid the offending sunscreen, as a 2nd exposure may result in exaggerated response.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Frederick Coville
Plastic Surgery 39 years experience
Not sure where?: I'm not sure where your rash is and so it is almost impossible to give you an answer. Yes it it possibly a heat rash. But after a week, that should have gotten better. Please see your family doctor or dermatologist. Be well, .
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Frederick Coville
Plastic Surgery 39 years experience
Impossible to say: I am sorry but it really is impossible to say what your rash is caused by without seeing it. Heat rash should have resolved by now. Please see a good dermatologist or your family doctor. Be well.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Richard Tholen
Plastic Surgery 41 years experience
Personal exam needed: Even though you have provided a description, actual examination of your rash is needed to provide a meaningful diagnosis. See a dermatologist if this persists or worsens.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Frederick Coville
Plastic Surgery 39 years experience
Not sure where?: I'm not sure where your rash is and so it is almost impossible to give you an answer. Yes it it possibly a heat rash. But after a week, that should have gotten better. Please see your family doctor or dermatologist. Be well, .
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Frederick Coville
Plastic Surgery 39 years experience
Impossible to say: I am sorry but it really is impossible to say what your rash is caused by without seeing it. Heat rash should have resolved by now. Please see a good dermatologist or your family doctor. Be well.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Lavinia Chong
Plastic Surgery 33 years experience
Dermatitis: Whether heat rash or reaction to the sunscreen, you seem to describe a form of "dermatitits". Itchiness, color change and bumpiness are typical of "contact dermatitis" and responds to eliminating the offending challenge, either sunscreen and/or sun. Calamine lotion and/or otc Cortaid (hydrocortisone) (steroid cream) may relieve your symptoms.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Gaston Moran Celayes
Dr. Gaston Moran Celayesanswered
Internal Medicine 26 years experience
Could be: Is very difficult for us to make a diagnosis without seeing the lesion and having more information. If you want to have an accurate diagnosis, you should contact your primary care physician.
Dr. Robert Alexander
Plastic Surgery 27 years experience
Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.
Dr. Reza Jarrahy
Plastic Surgery 25 years experience
Dermatitis: Sounds like some sort of contact dermatitis or heat given the timing of the symptoms and the event. If it doesn't get better with conservative mgmt over the next few days you should consult with a dermatologist.

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Last updated Sep 18, 2019

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