A 15 month-year-old female came to clinic with a history of fever for 2 days up to 101.7F° and a rash that the mother noticed on the toddler’s trunk the evening before. She had some rhinorrhea, but no cough, emesis, or emesis and did not seem to be in pain. She had no history of exposures to any new soaps, lotion, detergents, etc. She was not taking any medications. Her daycare had some children with fevers but the mother didn’t know if they also had rashes. She had been drinking and urinating well. She was otherwise well.
The pertinent physical exam showed a healthy appearing child who interacted and smiled. She was afebrile and her growth parameters were around the 75%. HEENT reveled clear rhinorrhea, with normal ears and pharynx. She had a few shotty anterior cervical nodes. Her trunk and proximal shoulders and legs had multiple 1-2 mm, uniformly diffuse macular lesions that were pink in color and blanched with pressure. The rest of her examination was normal.
The diagnosis of a viral exanthem was made and her mother was educated regarding symptomatic care and when she could return to daycare.
This is the first in a short case series of differential diagnoses of colored skin conditions.
A differential diagnosis by distribution and common pattern can be found here.
For green, blue and violet conditions, a review can be found here.
For black and white conditions, a review can be found here.
For brown and grey conditions, a review can be found here.
Note that any color can be a normal variant for an individual or is physiologic for a given state.
The skin is the largest organ of the body. It can be easily examined but for many clinicians continues to be difficult to describe what they are seeing. Analogies and comparisons are often used such as “It sort of looks like XXX,” or “It looks like atopic dermatitis but also YYY.” Skin lesions are described in many terms including morphology, size (using standard measurements), demarcation (well- or not well- demarcated), location, distribution and color. Morphologically lesions may be uniform or not uniform.
Primary morphology terms include:
- “Macule – flat lesion less than 1 cm, without elevation or depression
- Patch – flat lesion greater than 1 cm, without elevation or depression
- Plaque – flat, elevated lesion, usually greater than 1 cm
- Papule – elevated, solid lesion less than 1 cm
- Nodule – elevated, solid lesion greater than 1 cm
- Vesicle – elevated, fluid-filled lesion, usually less than 1 cm
- Pustule – elevated, pus-filled lesion, usually less than 1 cm
- Bulla – elevated, fluid-filled lesion, usually greater than 1 cm”
Secondary morphology terms include: erosion, fissure, lichenification, scaling, ulceration, serum (dry crust).
Distribution patterns include generalized, dermatomal, extensor, and photodistribution.
Color can also be difficult for people to describe both for patients and clinicians. Skin coloration is not uniform over the body and the changes from one area to the other are often not well-demarcated and are subtle. Color changes with high contrast (i.e. vermilion border, areola) are often easier for people to appreciate and articulate more accurately. Intensity of the coloration makes a difference (i.e. newborn jaundice with fluorescent quality or barely perceptible over the nose/face). The underlying skin tone, predominant skin color and ambient lighting conditions also makes large differences in how color is perceived and articulated.
Even color has different definitions which are commonly used interchangeably.
- Primary colors – red, yellow, blue
- Secondary colors – orange, green, violet
- Tertiary colors – red-orange, yellow-orange, yellow-green, blue-green, blue-violet, red-violet
- Hues – pure colors
- Tints – hue + white
- Tones – hue + grey
- Shades – hue + black
Because of these numerous issues, it can be helpful to describe the predominant color and then a secondary color. For example, red with some pink areas is different than pink with some red areas.
Red is in the visible spectrum of light with wavelengths ranging from 625 to 750 nm.
The differential diagnosis for red skin conditions includes:
- Burns – including sunburn
- Drug eruptions including Red man syndrome due to vancomycin
- Erythema nodosum
- Toxic erythema – Kawasaki disease, Scarlet fever, Staphylococcal scalded skin syndrome, Toxic shock syndrome
- Viral exanthems
- Multiple causes and specific locations
- Lupus erythematosus
- Phototoxic reactions
- Post-inflammatory erythema
- Pityriasis rosea
- Specific areas – red hands or palms, red scrotum or vulva
- Vascular lesions and problems
- Deep vein thrombosis
- Stasis dermatitis
- Red or “ginger” hair
- Red splinter lines in nails
Orange is in the visible spectrum of light with wavelengths ranging from 590-625 nm.
The differential diagnosis for orange skin conditions includes:
- Foreign body granuloma
- Lupus vulgaris
- Sebaceous lesions – adenoma, carcinoma, nevus sebaceum
- Histiocytosis, non-Langerhans
- Juvenile xanthogranloma
- Xanthoma disseenatum
- Pityriasis rubra pilaris
Yellow is in the visible spectrum of light with wavelengths ranging from 565-590 nm.
The differential diagnosis for yellow skin conditions includes:
- Adipose tissue such as fat herniation
- Connective tissue nevus
- Epidermal cysts
- Fixed drug eruption
- Sloughing skin
- Lichen aureus
- Actinic keratosis
- Seborrheic keratosis
- Biliary disease
- Hyperbilirubinemia, neonatal
- Obstructive liver disease
- Renal failure
- Sebaceous lesions – adenoma, carcinoma, nevus sebaceum
- Squamous cell carcinoma
- Pustular lesions
- Erythema toxicum neonatorum
- Pustular dermatotis
- Pustular psoriasis
- Transient neonatal pusular melanosis
- Solar elastosis
- Xanthomas and xanthadermatosis
- Multiple variations including specific locations such as tendon xanthoma
- Dystrophic nails
- Pachyonychia congenita
- Yellow nail syndrome
Questions for Further Discussion
1. What red skin conditions do you see often?
2. What orange skin conditions do you see often?
3. What yellow skin conditions do you see often?
4. What are indications for referral to a dermatologist?
- Disease: Viral exanthem | Viral Infections
- Symptom/Presentation: Rash
- Age: Toddler
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
Information prescriptions for patients can be found at MedlinePlus for this topic: Rashes
To view current news articles on this topic check Google News.
To view images related to this topic check Google Images.
To view videos related to this topic check YouTube Videos.
Elias M, Patel S, Schwartz RA, Lambert WC. The color of skin: red diseases of the skin, nails, and mucosa. Clinics in Dermatology. 2019;37(5):548-560. doi:10.1016/j.clindermatol.2019.07.017
Logan IT, Logan RA. The color of skin: yellow diseases of the skin, nails, and mucosa. Clinics in Dermatology. 2019;37(5):580-590. doi:10.1016/j.clindermatol.2019.07.019
Soundararajan V, Charny JW, Bain MA, Tsoukas MM. The color of skin: orange diseases of the skin, nails, and mucosa. Clinics in Dermatology. 2019;37(5):520-527. doi:10.1016/j.clindermatol.2019.07.014
Dermatology Exam: Learning the Language. Stanford Medicine 25. Accessed January 4, 2022. https://stanfordmedicine25.stanford.edu/the25/dermatology.html#serum
Visible spectrum. In: Wikipedia. ; 2021. Accessed January 4, 2022. https://en.wikipedia.org/w/index.php?title=Visible_spectrum&oldid=1062416030
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa