FS

Lumps and Bumps - Comprehensive Dermatological Guide

Warts

Warts are a common dermatological condition caused by human papillomavirus (HPV) infection. There are 150-200 subtypes of HPV that can affect the skin and mucosa, divided into mucosal and cutaneous types.

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  • Cutaneous HPV: Results in common warts.

  • Mucosal HPV: Subdivided into high-risk (e.g., HPV16, HPV18) and low-risk types. High-risk types can cause low or high-grade dysplasia, potentially leading to cancers.

History

  • Non-genital warts: Common in school children (20%). Transmitted person-to-person or via contaminated surfaces. They usually regress spontaneously within 1-2 years.

  • Numerous or persistent warts: Prompt consideration of immunosuppressive conditions like HIV, diabetes mellitus, or syndromes like epidermodysplasia.

  • Anogenital warts: Sexually transmitted, more common in adults. In young children, may be acquired perinatally or via person-to-person contact.

    • Children under 2: Sexual abuse accounts for about 1 in 5 cases.

    • Children over 3: Sexual abuse accounts for up to 45% of cases.

Signs and Symptoms

Warts can occur anywhere on the body, differing by anatomical location, morphology, and HPV subtype. They present as small, rough bumps on the skin or mucous membranes, and may be flesh-colored, white, pink, tan, or have a cauliflower-like surface. They can be a cosmetic concern, painful, or even cancerous (HPV16, HPV18). Types of warts include:

  • Common warts (Verruca vulgaris)

  • Plantar warts (Verruca plantaris)

  • Plane warts (Verruca plana)

  • Filiform and digitate warts

  • Butcher's warts

  • Epidermodysplasia verruciformis

Common Warts

Hyperkeratotic exophytic papules and nodules on fingers and dorsal hands.

Plantar Warts

  • Myomesial type: Sloping sides, central depression (anthill-like), tender with lateral and direct pressure, surrounded by yellow hyperkeratotic callus-like skin with discontinued skin lines.

  • Mosaic type: Thick exo- and endophytic hyperkeratotic papules and plaques coalescing into a mosaic pattern, commonly seen on dorsal hands, arms, and legs.

Plane Warts

Skin-colored to pink or brown papules and plaques with a smooth, flat-topped surface.

Filiform Warts

A cluster of fine fronds emerging from a narrow pedicle base, usually on the face, also described as digitate or finger-like warts.

Butcher's Warts

Caused by HPV7, affecting hands of butchers and those chronically exposed to cold, moist environments. Resemble common warts, numerous, and can appear as extensive verrucous plaques or papules on dorsal, palmar, or periungal areas of hands and fingers.

Epidermodysplasia Verruciformis

A rare autosomal recessive condition susceptible to skin infection with specific HPV types, or due to acquired immunodeficiency like HIV. Presents with widespread lesions in childhood (inherited type), with a predilection for sun-exposed sites.

Mucosal Warts

  • Oral warts: Affect buccal, gingival, labial mucosa, tongue, and hard palate. Small, soft, mucosal, white papules and plaques. Differentials include bite fibroma, early SCC, or hick's disease.

  • Condylomata acuminata: Primarily affects the anogenital region, ranging from discrete lesions to large cauliflower-like lesions.

  • Bowenoid papillosis: Seen in the anogenital region, represented as multiple pink to red-brown verrucous papillae/plaques. In females, a pap smear is important to exclude intraepithelial neoplasia.

  • Erythroplasia of Queyrat: Squamous cell carcinoma in situ of glabrous skin of vulva or penis, seen as a well-demarcated red plaque that may progress to invasive SCC.

Differential Diagnosis of Warts

Seborrheic keratosis, actinic keratosis, benign nevi. Must not miss squamous cell carcinoma (especially in anogenital lesions) and underlying immunosuppression or syndromes with extensive warts.

Investigations for Warts

Diagnosis usually clinical. Dermoscopy may help. Punch biopsy indicated for atypical presentations or to exclude SCC.

Cysts

A benign, round, worm-shaped, encapsulated lesion containing fluid or semi-fluid material. May be firm or fluctuant, distending the overlying skin.

History

Duration, changes in size, and symptoms of inflammation or infection.

Signs and Symptoms

Variably sized papules or nodules, round, movable under the skin, painless unless inflamed or infected. Assess for inflammation, infection, fluctuation, mobility, and tenderness.

Types of Cysts

True Cysts

Contain an epithelial lining (visible histologically and clinically).

  • Common Types:

    • Epidermoid cysts

    • Milium

    • Pilar cysts (trichilemmal cysts)

    • Pilonidal cysts

  • Less Common Types:

    • Vellus hair cysts

    • Steatocystoma

    • Hydrocystoma

False Cysts

Do not contain an epithelial lining.

Congenital Cysts

Present at birth.

Common Types of True Cysts

Epidermoid Cysts

Most common on the face and upper trunk, skin-colored to white-yellow papule or nodule (millimeters to centimeters). Visible comedonal-like opening or central punctum. Soft, cheese-like, sometimes malodorous content can be expressed. Rupture into the dermis causes an acute reaction and tender inflamed lesion, which can be mistaken for bacterial infection.

Milia

Small superficial epidermoid cysts (1-2 mm), white, sometimes grouped, frequently seen on the central face and periorbital region. Common on the face in newborns (40-50%), especially on the nose, but can also appear inside the mouth (Epstein pearls, Bohn nodules) or on the scalp, face, and upper trunk. Usually heal spontaneously within a few weeks after birth.

Pilar Cysts (Trichilemmal Cysts)

Most common on the scalp, sometimes with overlying alopecia. Solitary or multiple, relatively firm nodules.

Pilonidal Cysts

Most common in the upper gluteal cleft, associated with a sinus tract. History of draining malodorous contents, more common in men, and may be associated with the follicular occlusion tetrad (acne, hidradenitis suppurativa, dissecting cellulitis, and pilonidal cysts).

Less Common Types of True Cysts

Vellus Hair Cysts

1-3 mm lesions, skin-colored to brown papules, commonly on the trunk. May become inflamed. Nicking the cyst reveals vellus hairs in the contents.

Steatocystoma

2-10 mm skin-colored to pigmented papules/nodules, commonly on the trunk, axillae, or groin. Solitary (steatocystoma simplex) or multiple (steatocystoma multiplex). Can drain an oily fluid.

Hydrocystoma

  • Apocrine hydrocystoma: Solitary translucent papules on the eyelid margin.

  • Eccrine hydrocystoma: Solitary or multiple translucent to bluish papules on the face, becoming prominent with sweating.

False Cysts

Mucocele

Compressible, mucosal-colored to bluish papules/nodules, most commonly on the inner lower lip, caused by disruption of minor salivary ducts. May resolve spontaneously or require excision.

Digital Mucous Cysts

Skin-colored to translucent papules/nodules, most commonly on the digits, particularly the dorsal distal aspect of fingers. Compression of the nail matrix results in longitudinal nail deformity.

Ganglion Cyst

Soft cystic nodules up to 4 mm in diameter, commonly on the wrist more than the ankle. May resolve spontaneously but recurrence is common.

Pseudocyst of the Auricle

Painless unilateral swelling of the scaphoid fossa of the ear, more common in men.

Congenital Cysts

Dermoid Cysts

A chorestoma (benign tumor consisting of microscopically normal tissue derived from germ cell layers foreign to that body site). In the skin, made up of epidermal and dermal components (keratinocytes, hair follicles, hair, and sweat glands). Usually seen in children, recognized at birth when they enlarge or become inflamed. Firm skin-colored to pink subcutaneous nodules, most often located around the eyes (especially the lateral eyebrow). Midline lesions on the nose, scalp, or back may have intracranial extension.

Branchial Cleft Cysts

Located on the neck along the anterior border of the sternocleidomastoid muscle. May also present in the mandibular or preauricular region. Lack a primary cutaneous opening and typically present in older children and adults when infected or inflamed.

Differential Diagnosis of Cysts

Lipoma, fibroma, and abscesses. Must not miss non-benign tumors and underlying syndromes with multiple and extensive lesions.

Investigations for Cysts

Diagnosis is usually clinical, based on anatomic location, age of presentation, duration, and clinical features. FNA may help discern if a lesion is solid versus cystic and exclude malignancy. Imaging (ultrasound, CT, or MRI) may help differentiate cysts from solid masses.

Molluscum Contagiosum

A common viral skin infection caused by the molluscum contagiosum virus (a poxvirus).

History

  • Common in children: Enquire about exposure to infected individuals (spread by skin-to-skin contact more than fomites).

  • Sexual history in adults may be important.

  • Background immunocompromised state (HIV, atopic dermatitis): Molluscum contagiosum may be more extensive in patients with atopic dermatitis.

  • Usually resolves spontaneously over months to years in immunocompetent individuals.

Signs and Symptoms

Small round, skin-colored or pearly papules with central umbilication. Predilection for the face, skin folds, lateral trunk, thighs, buttocks, and genitals. Inflammatory reactions frequently occur (eczematous dermatitis surrounding lesions, inflammation of individual lesions, or Gianotti-Crosti-like syndrome).

Differential Diagnosis

  • Solitary or few lesions in a child: Milia, juvenile xanthogranuloma, or Spitz nevi.

  • In an adult: BCC.

  • Multiple lesions: Warts or papular eczema.

  • Immunocompromised host: Cryptococcus or histoplasmosis.

Investigations

History and clinical findings guide the diagnosis.

  • Dermoscopy: May see yellow-white lobular central structures surrounded by crowns of blood vessels.

  • Curettage or scraping: Saline or KOH mount may reveal large round molluscum bodies.

  • Biopsy: May be needed for confirmation in atypical cases; histology shows large round intracytoplasmic inclusion bodies.

Sporotrichosis

A chronic subcutaneous mycosis caused by the fungus Sporothrix schenckii. Dimorphic organism (yeast at 37°C, mould at 25°C).

History

Ask about exposure to contaminated soil, plants, or animals. The fungus is found in soil, decaying organic matter, and vegetation. Animal-to-human transmission is rare, except for exposure to infected cats in Brazil.

  • History of open wounds: Primarily transmitted through traumatic implantation of fungal conidia into the skin from plant materials.

  • Occupation: Nursery workers, florists, and gardeners acquire the disease from roses, sphagnum moss, and other plants.

  • Travel history: Sporothrix is present in the soil worldwide but endemic to Mexico, Central America, South America, and parts of South Africa. In temperate climates (US and Canada), the disease most often develops in gardeners (especially those growing orchids and roses).

  • Immune status: HIV, underlying malignancies (e.g., lymphoma), immunosuppressants (e.g., corticosteroids) as these can influence the presentation.

Signs and Symptoms

Presents as nodular lesions that ulcerate and form a linear pattern along the lymphatic channels. Infection may be limited to the site of infection (plaque sporotrichosis) or extend along proximal lymphatic channels (lymphangitic sporotrichosis).

Contact with the skin leads to the entry of fungal conidia. The presentation and course of sporotrichosis depend on the host immune response, size, and virulence of Sporothrix schenckii.

  • Physical examination: Look for characteristic linear lesions and assess lymph nodes for enlargement. Lymphocutaneous/sporotrichoid pattern is most common (75% of patients).

  • Initial presentation: Single papule at the site of injury (most commonly on the hand), appearing several weeks after inoculation. The lesion then becomes eroded or ulcerated, with a purulent discharge (generally not painful). Additional lesions appear weeks later as dermal and subcutaneous nodules and ulcers along the path of lymphatic drainage.

  • Less common variants:

    • Fixed ulcerated plaque: Occurs on the face of people with previous exposure (prevalent in Brazil due to transmission from infected cats).

    • Cutaneous dissemination: Papular nodules develop as a sign of systemic infection.

Differential Diagnosis

Granulomatous disorders (infectious and non-infectious).

  • Infectious: Cutaneous leishmaniasis and atypical mycobacterial infection (e.g., M. marinum).

  • Non-infectious: Sarcoidosis.

Investigations

Clinical suspicion guides laboratory testing.

  • Microscopy

  • Histopathology

  • Fungal culture (pus or tissue)

  • PCR

Sporotrichosis is most commonly identified by culture and microscopy, less often seen on histology. Histology may show multiple yeast forms of Sporothrix schenckii in the dermis, many organisms have a cigar shape.

Erythema Nodosum

History

  • Gender: More common in females than males.

  • Age: Commonly presents in the second to fourth decade of life.

  • Duration of symptoms: May last a few days to weeks, then slowly involute without scar formation. Discoloration is suggestive of a bruise.

  • Recent infections, medications, symptoms of possible underlying conditions.

Signs and Symptoms

Tender erythematous nodules, commonly on the anterior shins (no ulceration or drainage). Late lesions have a bruise-like appearance. Inquire about associated fever, arthralgia, and malaise.

  • Physical examination: Assess distribution of lesions, signs of systemic illness, and underlying conditions. Nodules and plaques may develop a bruise-like appearance.

Triggers

  • Common causes:

    • Idiopathic (most common)

    • Streptococcal infections (upper respiratory tract infections)

    • Sarcoidosis

    • Inflammatory bowel disease

    • Drugs (oestrogen, sulfonamides, penicillins).

  • Less common causes:

    • Other infections (TB, hepatitis B)

    • Neutrophilic dermatoses (SWEET syndrome)

    • Pregnancy

    • Drugs (TNF alpha inhibitors, checkpoint inhibitors)

    • Malignancy (underlying leukemia).

Differential Diagnosis

Other forms of panniculitis (e.g., erythema induratum - nodular vasculitis on the posterior aspect of the lower legs that may ulcerate), cellulitis, deep vein thrombosis, superficial thrombophlebitis.

Investigations

Lab tests may help identify an underlying cause or trigger, guided by history and clinical examination.

  • ASOT and anti-DNase B titers

  • Chest x-ray

  • Mantoux test

  • Pregnancy tests (if female of childbearing age)

  • Viral hepatitis panel

  • Fecal MCS (if diarrhea, consider a GIT referral)

  • Age-appropriate malignancy workup (guided by history and physical examination)

  • Punch biopsy (necessary to confirm the type of panniculitis).

Seborrheic Keratosis

History

  • Age: Usually appears during the fourth decade of life.

  • Duration: Increases in number with age.

  • Changes in size, shape, or color of the lesions, family history of skin cancer.

Signs and Symptoms

Waxy, stuck-on, tan, brown, or black papules or plaques (stuck-on appearance). The sudden appearance of many seborrheic keratoses is known as the sign of Leser-Trélat (rare, may be associated with an underlying malignancy). Spares the palms, soles, and mucosal surfaces.

Variants

  • Dermatosis papulosa nigra: Common in dark-skinned individuals, 1-5 mm hyperpigmented papules on the face.

  • Stucco keratosis: 1-4 mm gray-white papules on the lower extremities (especially dorsal feet and ankles of older adults).

  • Inverted follicular keratosis: Endophytic variant of seborrheic keratosis, tan to pink papule, typically on the face of adults.

Differential Diagnosis

Melanocytic nevi, verruca vulgaris, and dermatofibroma.

Investigations

Diagnosis of seborrheic keratosis is clinical. Dermoscopy can be useful. Punch biopsy or shave biopsy may be performed for atypical lesions (necessary to exclude non-benign lesions, especially melanoma and PCC).

  • Dermoscopy: Well-defined border, multiple milia-like cysts, multiple comedo-like openings.

  • Histology: Septae.