Quick Reference for Rashes, Pt 3

Vector

Mosquitoes

Chikungunya.  The rash is reddish with areas of discolored skin or maculopapular, meaning that there are areas of discolored skin with raised bumps.  The rash appears within the first 2-3 days of illness and concludes within 7-10 days.[1] 

Dengue.  The rash develops 3-5 days after the fever begins.  The transient, faint, reddish rash progresses to more pronounced spots or patches.  It begins on the torso, chest, and face before spreading to the arms and legs.  The skin may be warm or tender to the touch and itchy.  And it occurs concurrently with a high fever, muscle and joint pain, headache, and eye pain.  The rash resolves within a few days and may be followed by a peeling phase usually on the fingertips, toes, and other extremities.[2]

West Nile.  The rash appears 3-7 days after the onset of symptoms and is accompanied by the onset of fever.[3]  The rash is reddish and flat or slightly raised, and primarily on the torso and neck.  It lasts 7-14 days. 

Zika.  The rash is one of the most common symptoms.  The small red or purple bumps most often appear on the trunk or face first, and then spread to the arms and legs.  The rash lasts from 3 to 11 days, with 6 days being average.[4]

Scabies

Scabies bites cause an itchy, red rash on the skin.  An itching so intense that its victims will do anything to get rid of it.  An itching so intense that the sufferers cannot even sleep at night.  And indeed that is the biggest clue that the rash is scabies--the itching is worse at night.[5]

Ticks

All tick-borne illnesses

Bourbon virus.  The rash is maculopapular (it has both flat and raised areas).

Colorado tick fever.  The rash is maculopapular (also described and flat and pimply).

Lyme disease.  The rash features a characteristic bullseye around the site of the bite.

Rocky Mountain Spotted Fever. The rash associated with RMSF begins 2-5 days after the onset of symptoms.  The small, flat, pink, non-itchy spots first appear on the wrists, forearms, and ankles and sometimes spread to the trunk, palms and soles.  About 10% of patients never develop a rash and the decision to begin treatment should not be based on the presence of a rash.  Later, the rash turns red to purple.  This is a sign of severe progression of the disease and treatment should have already begun.

Other

Lomatium dissectum.   About 1 percent of people who use a fresh root tincture of Lomatium dissectum will develop a significant allergic rash.  (Other species do not cause the rash.)  This occurs only if the fresh root tincture is taken alone, rather than in conjunction with other herbs.  There is no itching or discomfort with this rash, but it looks bad.  The rash begins within eight hours of taking the tincture.  It covers the whole body and is deep red to purple. 

Salmonella.  A faint rash (rose spots) may appear on the abdomen and trunk. 

Antibiotics

Amoxicillin may cause two different types of rashes.  The first is hives, which are small white or red raised, itchy bumps on the skin that develop after taking only one or two doses.  The presence of hives suggests the possibility of an anaphylactic reaction.  If the patient has difficulty breathing or shows signs of swelling, he should be seen by a physician immediately.  Do not administer any more amoxicillin or any other antibiotic in the penicillin family.

The other rash is a maculopapular rash, which develops 3-10 days after starting amoxicillin treatment.  Flat, red patches on the skin are accompanied by smaller, paler patches.   Girls are more likely than boys to develop this rash.[6]

SMZ-TMP[7]

Nutritional

Vitamin B2 deficiency, oily skin rashes on the scrotum or vulva, the little cleft above the lips (anatomically known as the philtrum, learn something new every day), and/or the nasolabial folds ("laugh lines" between the nose and the mouth)

Vitamin B7 deficiency, scaly red rash around the eyes, nose, mouth, and genitalia.

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[1] https://www.verywellhealth.com/chikungunya-virus-8673850

[2] https://www.acibademhealthpoint.com/the-dengue-fever-skin-rash-symptoms-treatment/

[3] https://pmc.ncbi.nlm.nih.gov/articles/PMC557978/

[4] https://www.verywellhealth.com/zika-rash-8628070

[5] https://www.mayoclinic.org/diseases-conditions/scabies/symptoms-causes/syc-20377378

[6] https://www.healthline.com/health/parenting/amoxicillin-rash#appearance

[7] Joseph Alton, et al., Alton’s Antibiotics, 2018, 166.