Skin Disorders
Bookmark and Share
   Acquired Melanocytic Nevocellular Nevi
   Acral Lentiginous Melanoma
   Acute HIV Syndrome
   Acute Lymphangitis
   Acute Sun Damage
   Adult T Cell Leukemia
   Adverse Cutaneous Drug Reactions
   Alopecia Areata
   Androgenetic Alopecia
   Aphthous Ulcer
   Bacillary Angiomatosis
   Bacterial Infections
   Basal Cell Carcinoma
   Basal Cell Nevus Syndrome
   Behcet's Syndrome
   Benign Cutaneous Neoplasms
   Capillary Hemangioma of Infancy
   Cat-Scratch Disease
   Chronic Lupus Panniculitis
   Chronic Venous Insufficiency
   Clark Melanocytic Nevus
   Congenital Nevomelanocytic Nevus
   Crest Syndrome
   Cutaneous Candidiasis
   Cutaneous Larva Migrans
   Cutaneous Lupus Erythematosus
   Cutaneous and Mucocutaneous Leishmaniasis
   Cutaneous Pseudomonas Aeruginosa Infections
   Cutaneous Reactions to Arthropod Bites
   Cutaneous T Cell Lymphoma
   Desmoplastic Melanoma
   Disseminated Coccidioidomycosis
   Disseminated Cryptococcosis
   Disseminated Gonococcal Infection
   Disseminated Intravascular Coagulation
   Drug Hypersensitivity Syndrome
   Drug-Induced Acute Urticaria
   Drug-Induced Pigmentation
   Eosinophilic Folliculitis
   Erysipelas and Cellulitis
   Erythema Infectiosum
   Erythropoietic Protoporphyria
   Exanthematous Drug Reactions
   Exfoliative Erythroderma Syndrome
   Extramammary Paget's Disease
   Eye Stye
   Fixed Drug Eruption
   Gangrenous Cellulitis
   Genital Candidiasis
   Giant Cell Arteritis
   Glucagonoma Syndrome
   Graft Versus Host Disease
   Hand-Foot-and-Mouth Disease
   Herpes Gestationis
   Herpes Simplex Virus: Genital Infections
   Herpes Simplex Virus Infection
   Herpes Simplex Virus: Infections Associated Systemic Immunocompromise
   Herpes Simplex Virus
   Herpes Zoster
   HIV Associated Lipodystrophy Syndrome
   Human Papillomavirus: Mucosal Infections
   Human Papillomavirus: Squamous Cell Carcinoma In Situ
   Human Papillomavirus
   Hypersensitivity Vasculitis
   Hypertrophic Scars and Keloid
   Impetigo and Ecthyma
   Infectious Exanthems
   Infectious Folliculitis
   Infective Endocarditis
   Infestations of the Skin
   Kaposi's Sarcoma
   Kawasaki's Disease

Home :: Cutaneous Reactions to Arthropod Bites

Cutaneous Reactions to Arthropod Bites

Cutaneous reactions to arthropod bites (CRAB) are inflammatory and/or allergic reactions, characterized by an intensely pruritic eruption at the bite sites hours to days after the bite, manifested by solitary or grouped urticarial papules, papulovesicles, and/or bullae that persist for days to weeks; patients are often unaware of having been bitten. In some cases, systemic symptoms may occur, ranging from mild to severe, with death occurring from anaphylactic shock. Arthropod bites are also the method of transmission of many systemic infections and infestations.

Causes of Cutaneous Reactions to Arthropod Bites

  • Mites Produce pruritus and/or allergic reactions through salivary proteins deposited during feeding. Harvest mites (chiggers) may present as intense pruritus on the ankles, legs, belt line; mites usually fall off after feeding or may be scratched off. In nonsensitized individuals, 1 to 2 mm pruritic papules are seen. In sensitized individuals, CRAB may be papular urticaria, vesiculation, or granulomatous reaction with fever and lymphadenopathy.
  • Ticks Reactions include foreign body reactions, reactions to salivary secretions, reactions to injected toxins, and hypersensitivity reactions. Tick paralysis is caused by a toxin secreted in the saliva of the tick.
  • Spiders Brown recluse spider (Loxosceles reclusa) bite causes reactions ranging from mild urticaria to full-thickness necrosis (loxoscelism). "Widow" spiders (Latrodectus) inject a venom that contains a neurotoxin. (α­latrotoxin) producing reactions at the bite site as well as varying degrees of systemic toxicity.
  • Scorpion Venom also contains a neurotoxin that can cause severe local and systemic reactions.
  • Blister Beetles Contain the chemical cantharidin, which produces blister when the beetle is crushed on the skin.
  • Black Flies Bites produce local reactions as well as black fly fever, characterized by fever, headache, nausea, generalized lymphadenitis.
  • Nonbiting Flies Flies commonly feed on open wounds, exudates, and skin ulcers and may deposit eggs at these sites, resulting in wound myiasis. Fly larvae can burrow into injured or normal skin, invading through the epidermis into the dermis, resulting in furuncular myiasis. In some cases, larvae move about the subcutis (migratory myiasis), mimicking the pattern of cutaneous larva migrans.
  • Bedbugs Nocturnal feedings produce a linear arrangement of papular urticaria.
  • Hymenoptera Bees, hornets, wasp bites can produce painful stings, and anaphylaxis in the sensitized individual.
  • Caterpillars and Moths Hairs can produce local irritant and allergic reactions.
  • Fleas (Cat, Dog, Bird) Bites tend to cause more local reactions than human flea bites.
  • Chigoe or Sand Fleas(Tunga penetrans) Recently impregnated female flea penetrates skin of a human host, burrows into epidermis to dermal-epidermal junction, where she feeds on blood drawn from host vessels in superficial dermis. Enlargement of the buried flea to 5 to 8 mm causes local pain in the infested skin. Mature eggs (150 to 200) are extruded singly from a terminal abdominal orifice during a period of 7 to 10 days. The female dies shortly after egg extrusion, and the infested tissues collapse around it; ulcerations can occur at the site. Inflammation and secondary infection can arise if parts of the flea are retained in the tissue.

Symptoms of Cutaneous Reactions to Arthropod Bites

  • Allergic reactions
  • Skin rash
  • Itch


Clinical diagnosis, at times confirmed by lesional biopsy.


Larvae in Skin Tungiasis: remove flea with needle, scalpel, or curette, attempting to remove all flea parts; oral thiabendazole, (25 mg/kg/d) or albendazole (400 mg/d for 3 days), effective for heavy infestations. Furuncular myiasis: suffocate larvae by covering the larvae with vaseline; remove the following day when dead.

Glucocorticoids Potent topical glucocorticoids given for a short time are helpful for intensely pruritic lesions. In some cases, a short tapered course of oral glucocorticoids can be given for extensive CRAB that are persistent.

Antimicrobial Agents Secondary Infection Antibiotic treatment with topical agents such as mupirocin ointment or antistaphylococcal/ antistreptococcal agents if secondary infection is present.

Systemic Infection/Infestation Treat with appropriate antimicrobial agent.


Avoid contact with arthropods. Apply insect repellent such as diethyltoluamide(DEET) to skin. Apply permethrin spray (permanone [USA]) to clothing. Use passive measures such as screens, nets, clothing. Treat flea-infested cats and dogs; spray household with insecticides (e.g., malathion, 1 to 4% dust) with special attention to baseboards, rugs, floors, upholstered furniture, bed frames, mattresses, and cellar.

More Skin Disorders
   Langerhans Cell Histiocytosis
   Leg Ulcers
   Lentigo Maligna
   Leukemia Cutis
   Livedo Reticularis
   Localized Infection
   Lupus Erythematosus
   Lyme Borreliosis
   Lymphogranuloma Venereum
   Lymphomatoid Papulosis
   Malignant Melanoma of the Mucosa
   Mammary Paget's Disease
   Mastocytosis Syndromes
   Merkel Cell Carcinoma
   Metastatic Cancer to the Skin
   Molluscum Contagiosum
   Mycobacterium Fortuitum Complex Infection
   Mycobacterium Marinum Infection
   Mycobacterium Ulcerans Infection
   Necrobiosis Lipoidica
   Neisseria Gonorrhoeae Infections
   Nodular Melanoma
   Nodular Vasculitis
   Nongenital Herpes Simplex Virus Infection
   North American Blastomycosis
   Oral Hairy Leukoplakia
   Oropharyngeal Candidiasis
   Other Viral Infections
   Papulosquamous Conditions
   Pediculosis Capitis
   Pediculosis Pubis
   Photoallergic Drug Induced Photosensitivity
   Phototoxic Drug Induced Photosensitivity
   Pitted Keratolysis
   Pityriasis Versicolor
   Polyarteritis Nodosa
   Polymorphous Light Eruption
   Porphyria Cutanea Tarda
   Port-Wine Stain
   Premalignant and Malignant Skin Tumors
   Pressure Ulcers
   Pruritic Urticarial Papules
   Pseudoxanthoma Elasticum
   Pyogenic Granuloma
   Radiation Dermatitis
   Raynaud's Disease
   Reiter's Syndrome
   Rocky Mountain Spotted Fevers
   X-Linked Hyper-IgM Syndrome
   Xeroderma Pigmentosum
   Yellow Fever
   Yellow Nail Syndrome
   Zinc Deficiency

Skin Disorders || Contact Us || Tweet

Copyright © All Rights Reserved.

Disclaimer - The data contained in the Web pages is provided for the purpose of educational purposes and information only. It is not intended nor implied to be a substitute for professional medical advice and shall not create a physician - patient relationship. We are not responsible for any consequence resulted from using this information. Please always consult your physician for medical advices and treatment.