Table 1: Historical Findings That Suggest Etiologies for Pruritus
| HISTORICAL FINDING | POSSIBLE ETIOLOGIES |
|---|---|
New cosmetics or creams | Allergic contact dermatitis, urticaria, photodermatitis |
New medications, supplements, or illicit drugs | Urticaria, fixed drug eruptions |
Recent travel | Pediculosis, scabies infestation, photodermatitis, urticaria |
Hobby or occupational exposure to solvents, adhesives, cleaners | Irritant contact dermatitis, xerosis, atopic dermatitis, eczema |
New animal exposures | Flea infestation, allergic contact dermatitis, urticaria |
Sick contacts, especially those with febrile diseases and rashes | Rubeola, mumps, varicella, scarlet fever, cellulitis, fifth disease, folliculitis |
Unexplained weight changes, menstrual irregularity, heat/cold intolerance | Thyroid disease with secondary urticaria or xerosis |
Unexplained weight loss, night sweats, unexplained fevers, fatigue | Lymphoma with secondary generalized pruritus |
Malaise, nausea, decreased urine output | Renal failure with generalized pruritus |
Table 2: Dermatologic Etiologies for Pruritus
| ETIOLOGY | FEATURES |
|---|---|
Allergic/irritant contact dermatitis | Sharply demarcated, erythematous lesion with overlying vesicles |
Reaction within two to seven days of exposure | |
Atopic dermatitis | Pruritic area where rash appears when scratched in patients with atopic conditions (e.g., allergic rhinitis, asthma) |
Involvement of flexor wrists and ankles, as well as antecubital and popliteal fossae | |
Bullous pemphigoid | Initially pruritic urticarial lesions, often in intertriginous areas |
Formation of tense blisters after urticaria | |
Cutaneous T-cell lymphoma (mycosis fungoides) | Oval eczematous patch on skin with no sun exposure (e.g., buttocks) |
Possible presentation of new eczematous dermatitis in older adults | |
Possible presentation of erythroderma (exfoliative dermatitis) | |
Dermatitis herpetiformis | Rare vesicular dermatitis affecting the lumbosacral spine, elbows, or knees |
Dermatophyte infection | Localized pruritus and rash characterized by peripheral scaling and central clearing |
Can occur on several sites, including the feet, scalp, trunk, and groin | |
Folliculitis | Pruritus out of proportion to appearance of dermatitis |
Papules and pustules at follicular sites on chest, back, or thigh | |
Lichen planus | Lesions often located on the flexor wrists |
Characterized by the six P's (pruritus, polygonal, planar, purple, papules, plaques) | |
Lichen simplex chronicus | Localized, intense pruritus |
Initial erythematous, well-defined plaques with excoriations lead to thickened, lichenified, violaceous patches if scratching continues | |
Pediculosis (lice infestation) | Occiput in school-aged children; genitalia in adults (sexually transmitted) |
Psoriasis | Plaques on extensor extremities, low back, palms, soles, and scalp |
Scabies | Burrows in hand web spaces, axillae, and genitalia |
Hyperkeratotic plaques, pruritic papules or scales | |
Face and scalp affected in children but not in adults | |
Sunburn | Possible photosensitizing cause (e.g., with use of nonsteroidal anti-inflammatory drugs or cosmetics) |
Urticaria (hives) | Intensely pruritic, well-circumscribed, erythematous, and elevated wheals |
Lesions may coalesce and wax and wane over several hours | |
Xerosis | Intense pruritus, often during winter months in northern climates |
Involvement of back, flank, abdomen, waist, and lower extremities | |
More common in older persons |
Table 3: Systemic Etiologies for Pruritus
Autoimmune |
Dermatitis herpetiformis |
Dermatomyositis |
Linear immunoglobulin A disease |
Sjögren syndrome |
Hematologic |
Hemochromatosis |
Iron deficiency anemia |
Mastocytosis |
Plasma cell dyscrasias |
Polycythemia vera |
Hepatobiliary |
Biliary cirrhosis |
Chronic pancreatitis with obstruction of biliary tracts |
Drug-induced cholestasis |
Hepatitis, particularly hepatitis C |
Sclerosing cholangitis |
Infectious disease |
AIDS |
Infectious hepatitis |
Parasitic disease (giardiasis, onchocerciasis, schistosomiasis, ascariasis) |
Prion disease |
Malignancy |
Leukemia |
Lymphoma |
Multiple myeloma |
Solid tumors with paraneoplastic syndrome |
Metabolic and endocrine |
Carcinoid syndrome |
Chronic renal disease |
Diabetes mellitus |
Hyper/hypothyroidism |
Hyperparathyroidism |
Neurologic |
Cerebral abscess |
Cerebral tumor |
Multiple sclerosis |
Stroke |
Other |
Drug ingestion |
Eating disorders with rapid weight loss |
Neuropsychiatric disorders |
Pregnancy |
References:
1. American Family Physician: A Diagnostic Approach to Pruritus
http://www.aafp.org/afp/2011/0715/p195.html
2. NCBI Chronic Pruritus and Treatment
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119985/
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