Folliculitis is an inflammation of hair follicles related to infection, chemical irritation, or physical injury to the skin. It typically involves a superficial bacterial infection of the hair follicles with purulent material in the epidermis.
Folliculitis is usually caused by S. aureus, and nasal carriage of this organism is a risk factor for folliculitis. "Hot tub folliculitis" or "whirlpool-associated folliculitis" is often attributed to Pseudomonas species and occurs in inadequately chlorinated hot tubs, whirlpools, and swimming pools. Symptoms of uncomplicated folliculitis and whirlpool-associated Pseudomonas folliculitis are often mild and self-limited, and patients do not seek medical attention.
Individuals exposed to whirlpool footbaths at nail salons are at risk for mycobacterial furunculosis. Candida species are implicated in patients receiving broad-spectrum antibiotics or glucocorticoids or who are otherwise immunocompromised.2
The most common sites of involvement for folliculitis are the apocrine areas of the upper back, chest, buttocks, hips, and axilla, but folliculitis can develop in any hair-bearing region of the body, especially in areas of repeated shaving. Folliculitis presents with clusters of pruritic, erythematous lesions that are usually <5 mm in diameter, with pustules sometimes present at the centers.2 Pseudomonal folliculitis can develop over areas exposed to contaminated water, and lesions are often larger (up to 3 cm in diameter).
Pseudofolliculitis is a related noninfectious condition more commonly seen in blacks secondary to shaving. It occurs when the hair follicle becomes trapped and, instead of exiting the follicle, curls and grows into the follicular wall. Such findings in the beard region are called "sycosis barbae" or "folliculitis barbae" and can progress to deep infections that can cause facial scarring (see chapter 250, "Skin Disorders: Face and Scalp").
Folliculitis is diagnosed clinically. It should be differentiated from other disorders, such as acne vulgaris, impetigo, fungal infections, contact dermatitis, scabies, insect bites, and viral disorders such as herpes.
Treatment/Disposition and Follow-Up
For simple cases of uncomplicated folliculitis or hot tub folliculitis, stopping exposure or removing the offending agent and twice-daily cleansing with mild hand soap often suffices. Lesions usually resolve spontaneously, but if desired, warm compresses may be applied several times daily, and a topical antibiotic such as bacitracin or polymyxin B can also be used. Shaving should be avoided in the involved areas. Pseudofolliculitis is managed by allowing the hairs to grow 2 to 3 mm above the surface and afterward using commercially available razors designed for this condition. For painful or more extensive cases, oral antibiotics with activity against Streptococcus and Staphylococcus, such as cephalexin, dicloxacillin, or azithromycin, are recommended.
Hidradenitis suppurativa is a recurrent, suppurative, and scarring disease of the apocrine glands, most commonly found in the axillae and pubic regions of women and people of African descent. The disorder is neither contagious nor due to poor hygiene. Diagnosis is clinical. Identification and treatment are discussed in chapter 252, "Skin Disorders: Groin and Skinfolds."
Pilonidal abscesses are located along the superior gluteal fold. Some think that a pilonidal sinus forms along the gluteal fold possibly at the time of embryogenesis, although others believe it to be an acquired condition secondary to local soft tissue trauma. The sinuses are lined with squamous epithelium and hair, and blockage of the sinus tract with hair and other keratinous material leads to bacterial invasion and infection. The causative organisms typically are normal skin flora, with Staphylococcus species being the most common. Contamination with peritoneal and fecal organisms is also possible.
Patients tend to develop symptoms in their late teens and early twenties, and without definitive surgical treatment, they tend to suffer recurrent infections, sometimes developing a chronic draining fistulous tract. Pilonidal abscess is a tender, swollen, and fluctuant nodule located along the superior gluteal fold (Figure 152-7).
Pilonidal abscess. Redness, fluctuance, and tenderness in the gluteal cleft are seen with a pilonidal abscess. [Photo contributed by Louis La Vopa, MD. Reproduced with permission from Knoop K, Stack L, Storrow A, Thurman RJ: Atlas of Emergency Medicine, 3rd ed. © 2010, McGraw-Hill, New York.]
ED treatment is incision and drainage, with care taken to remove excess hair and debris from the abscess cavity. See "Incision and Drainage Procedure" given earlier for further recommendations. Antibiotics generally are not needed. Outpatient surgical referral should be recommended for definitive treatment. This typically consists of wide surgical excision and healing by secondary intention. Surgical treatment, although often successful, may involve difficult wounds and a long healing time. There is a debate in the surgical literature over primary closure versus open healing for pilonidal abscesses. When surgical treatment involves primary closure, wounds heal more quickly but are associated with an increased risk of recurrence.56 Performing less extensive procedures whenever possible is often in the patient's best interest.
INFECTED EPIDERMOID AND PILAR CYSTS
Epidermoid cysts originate from the epidermis, and pilar cysts originate from hair follicles; both contain a thick, cheesy collection of keratin, not sebum. True sebaceous cysts, as these cysts have erroneously been called in the past, are rare. Sebaceous glands occur diffusely throughout the body. Blockage of the duct of a sebaceous gland may lead to development of a glandular cyst that can exist for a long period without becoming infected. Once bacterial invasion occurs, abscess formation is common. An infected epidermoid or pilar cyst is an erythematous, tender, fluctuant cutaneous nodule. Simple incision and drainage is the appropriate ED treatment. The cyst always contains a capsule that must be removed to prevent further infection. Capsule excision is typically done at follow-up when the initial inflammation has improved or resolved. Occasionally, the wall of the sac can be grasped with a forceps and removed at the time of drainage.
Bartholin gland abscesses are common in women of reproductive age. An abscess in a perimenopausal woman requires gynecologic follow-up to exclude carcinoma. The Bartholin glands are a pair of pea-sized glands located in the labia minora in the 4 and 8 o'clock positions. They are not palpable if in a noninfected state. Infections are polymicrobial, including vaginal flora, anaerobes, and, in an important minority, Neisseria gonorrhoeae and Chlamydia trachomatis. Examination of the labia typically reveals a fluctuant 2- to 4-cm mass.
Definitive treatment is marsupialization of the abscess to prevent recurrence. The technique is detailed in Figure 152-8. See chapter 102, "Vulvovaginitis" for further discussion.
Incision and insertion of the Word catheter. A. Make a 0.5-cm-long stab incision on the mucosal surface of the labia minora. B. The cavity has been evacuated and the Word catheter inserted. C. The balloon is inflated with saline. [Reproduced with permission from Reichman EF, Simon RR: Emergency Medicine Procedures, © 2004, Eric F. Reichman, PhD, MD, and Robert R. Simon, MD.]
Paronychia and felons are discussed in chapter 283, "Nontraumatic Disorders of the Hand."
Perirectal abscesses are discussed in chapter 85, "Anorectal Disorders."
Sporotrichosis is a mycotic infection caused by the fungus Sporothrix schenckii.
Sporotrichosis occurs worldwide but is most common in tropical and subtropical zones. It is endemic in Central and South America and in Africa. The organism is found most commonly in soil, sphagnum moss, and decaying vegetable matter. It is a common disease among florists, gardeners, and agricultural workers. Inoculation into the host most often occurs when a spine or barb on a plant punctures the skin during handling. Approximately 10% to 62% of patients relate infection to penetrating trauma from plant thorns, wood splinters, or contaminated organic material. The largest outbreak of sporotrichosis in the United States occurred in 1988 and involved 15 states and 84 persons, all of whom handled conifer seedlings shipped in sphagnum moss contaminated with S. schenckii.
Transmission from infected animals, especially cats, has been documented. Veterinary workers, animal handlers, and cat owners are therefore at increased risk. The typical patient is a healthy young adult, but the infection can also occur in immunocompromised individuals such as those with alcoholism, diabetes mellitus, hematologic malignancy, organ transplantation, or human immunodeficiency virus infection.
S. schenckii is a thermally dimorphic fungus that changes from its mycelial form to its yeast form on entering a body temperature environment. Disease is usually limited to local cutaneous or lymphocutaneous areas. Osteoarticular involvement, including osteomyelitis, septic arthritis, bursitis, and tenosynovitis, occurs and may extend from a local cutaneous infection or may be secondary to hematogenous spread. Although less common, transmission may occur through inhalation of the fungus through the upper respiratory tract, and subsequent hematogenic dissemination can occur. When inhaled, granulomatous pneumonitis with cavitation may arise.
The incubation period averages 3 weeks following initial inoculation, but varies from a few days to several weeks. After the fungus enters the body through a break in the skin, three types of localized infections may occur. The fixed cutaneous type is characterized by lesions restricted to the site of inoculation and may appear as a crusted ulcer or verrucous plaque (Figure 152-9). Local cutaneous type infections also remain local but present as a subcutaneous nodule or pustule. The surrounding skin becomes erythematous and may ulcerate, resulting in a chancre. Local lymphadenitis is common. The lymphocutaneous type is the third and most common type. It is characterized by an initial painless nodule or papule at the site of inoculation that later develops subcutaneous nodules with clear skip areas along local lymphatic channels (Figure 152-10). The local reactions in all three types of infections tend to be relatively painless but show no signs of improvement without treatment.
Fixed sporotrichosis. The ulcer and surrounding erythema of fixed cutaneous sporotrichosis could be confused with a brown recluse spider bite. [Reproduced with permission from Knoop K, Stack L, Storrow A: Atlas of Emergency Medicine, 2nd ed. © 2002, McGraw-Hill, New York.]
Sporotrichosis. Chronic lymphocutaneous type—an erythematous papule at the site of inoculation on the index finger with a linear arrangement of erythematous dermal and subcutaneous nodules extending proximally in lymphatic vessels of the dorsum of the hand and arm. [Reproduced with permission from Wolff K, Johnson RA: Fitzpatrick's Color Atlas and Synopsis of Clinical Dermatology, 6th ed. © 2009, McGraw-Hill, New York.]
Patients occasionally develop extracutaneous illness from what is most probably hematogenous spread. Most cases of extracutaneous sporotrichosis involve the skeletal system. An indolent form of monoarticular arthritis is the most common symptom. Osteomyelitis, tenosynovitis, and carpal tunnel syndrome are occasionally seen as well. Multiarticular arthritis is usually only seen in patients with immunocompromise. Pulmonary involvement is rare, typically occurring in elderly alcoholic males and clinically resembling tuberculosis. Chronic lymphocytic meningitis can be a delayed complication of sporotrichosis infection and should be considered in patients with chronic meningeal symptoms.
History and physical findings are the keys to diagnosis. Fungal cultures are the best way to isolate the fungus, and tissue biopsy cultures often are diagnostic. Pus, synovial fluid, sputum, blood, or tissue fragment is suitable for culture.
Routine laboratory tests are nonspecific, but an increased WBC count, eosinophil count, and erythrocyte sedimentation rate may occur. The differential diagnosis includes tuberculosis, subcutaneous abscesses of tularemia, cat-scratch disease, leishmaniasis, staphylococcal lymphangitis, paracoccidioidomycosis, chromoblastomycosis, blastomycosis, bacterial pyoderma, primary syphilis, and infections caused by atypical mycobacteria such as Mycobacterium marinum.
Itraconazole (100 to 200 milligrams daily for 3 to 6 months) is the treatment of choice for localized and systemic infections. Fluconazole is less effective than itraconazole and should be reserved for those few patients not tolerating itraconazole. Ketoconazole has shown even poorer results than fluconazole. IV amphotericin B is effective, but adverse reactions limit its use to disseminated forms of the disease. In endemic regions or in epidemic outbreaks, a saturated solution of potassium iodide is an effective low-cost alternative.