Yellow
With jaundice, the shade of yellow varies with the level of the
bilirubin, ranging from lemon-yellow with anemia to deep yellow. Pernicious
anemia produces a bright yellow tint with a contrasting red tongue. Nephrotic
syndrome produces the pallor of anemia that combines with increased
carotene-binding globulin to produce a sallow-yellow cast. Red-brown lesions of
cutaneous tuberculosis (lupus vulgaris) are
yellow-brown, like apple jelly, on diascopy. Xanthelasma are waxy yellow lipid
deposits. Lesions of pseudoxanthoma elasticum look like yellowish plucked
chicken skin. Urate crystals produce a yellow translucence within tophi. Yellow
nails occur with lymphedema or chronic lung disease. Bright yellow urine appears
with phenacetin, quinacrine, riboflavin, and bilirubin (in which the foam is
also yellow). CMV retinitis has a yellowish retinal exudate like crumbled
cheese. A yellow visual halo is characteristic of both digoxin intoxication and
acute glaucoma.
Orange
Carotenemia causes the skin to turn orange-yellow, but the sclera
remain white. Orange urine can result from rhubarb, senna, Azulfidine
(sulfasalazine), Pyridium (phenazopyridine), or rifampin (which can even cause
orange tears). Patients with pityriasis rubra pilaris
may develop a striking orange skin color, especially on their palms and soles.
Tangier disease is marked by orange tonsils.
Blue/Gray
Blue-gray skin color can result from gold (chrysiasis), silver
(argyria), metastatic melanoma, ochronosis, chloroquine, minocycline, and
amiodarone (due to blue lipofuscin photodermatitis). Chlorpromazine produces a
blue-purple “visage mauve.†Blue sclera are typical for osteogenesis
imperfecta. Cyanosis caused by reduced hemoglobin is purplish-blue to
heliotrope. The skin in polycythemia is reddish-blue; in methemoglobinemia (a
result of dapsone treatment), chocolate blue; in sulfhemoglobinemia, lead or
mauve-blue. In Raynaud syndrome, white blanching turns to slate-blue cyanosis,
to livid purple, and finally to deep red. The rare finding of phlegmasia cerulea
dolens occurs with massive deep vein thrombosis. Distal embolism may produce a
blue toe. Gunmetal grey purpura is characteristic of meningococcemia. Blue urine
may be a product of amitriptyline, triamterene, senna, or indigo blue. Blue nail
lunulae are seen in argyria, Wilson disease, and antimalarial treatment. A bluish cervix is a
marker of pregnancy. The pharyngeal pseudomembrane of diphtheria is blue-white
(to gray-green). Blue-tinted vision occurs with optic ischemia and
phosphodiesterase inhibitors (sildinafil).
Green
Green purulence indicates the presence of a copper-containing
myeloperoxidase found in leukocytes. Pseudomonas
infection tints the nails green. Green urine may result from urinary copper,
Pseudomonas infection, biliverdin, phenol, or gross
hematuria in a patient with red-green color blindness. In iritis, a blue iris
may become green due to vascular congestion. Anemia often produces a greenish
waxy pallor.
Gold/Copper/Silver
The golden iridic ring in Wilson disease is a classic example, but
desipramine also produces a gold iris. Tuberculous peritonitis produces a
bronzing of the skin, especially on the abdomen. Lesions of secondary syphilis
are reminiscent of a copper penny in color and shape. Silver stools may rarely
occur with ampullary carcinoma, resulting from acholic stools with bleeding. The
mica scales of psoriasis are silver-colored.
Purple
The heliotrope eyelid rash of dermatomyositis may have a delicate
lilac color. Purple striae are highly suggestive of Cushing syndrome.
Plum-colored nodules are found in cutaneous lymphoma. Currant jelly sputum is
classic for Klebsiella infection. Erysipeloid has a
deep red-purple cast. Kaposi sarcoma appears as deep purple papules. The coup de
sabre lesion of localized scleroderma (morphea) is white and atrophic, with a
violaceous edge. Amyloidosis causes waxy pink-purple periorbital patches.
Ethionamide may cause a lilac brown photodermatitis. Porphobilinogen may produce
purple urine.
Black
A jet-black skin lesion is classic for melanoma. Velvety black
patches of acanthosis nigricans suggest insulin resistance. Black, tarry stools
indicate melena from upper gastrointestinal bleeding. Black urine occurs with
alcaptonuria, tyrosinosis, methyldopa, methocarbamol, phenol, malaria
(blackwater fever), methemoglobinemia, and cascara.