Friday, December 23, 2016

Pruritus: Differential Diagnosis

Table 1: Historical Findings That Suggest Etiologies for Pruritus

HISTORICAL FINDINGPOSSIBLE 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

ETIOLOGYFEATURES
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/

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.