What are the causes of skin pain on the back of the fingertip?

Causes of Skin Pain on the Back of the Fingertip

Skin pain on the back of the fingertip most commonly results from infectious causes (paronychia, felon, cellulitis), traumatic injury to the nail apparatus or fingertip soft tissues, or inflammatory conditions related to nail disorders. 1, 2, 3

Infectious Causes

Paronychia (Nail Fold Infection)

• Acute bacterial paronychia is the most common fingertip infection, occurring when organisms enter through breaches in the skin around the nail fold, causing painful swelling, erythema, and tenderness of the periungual tissue 1, 4, 3
• The infection typically follows localized trauma such as nail biting, hangnails, manicures, or chronic water immersion 1, 3
• Candida paronychia presents with chronic swelling of the posterior nail fold, pain with pressure and movement of the nail, and commonly affects individuals with wet occupations 5, 4
• Secondary bacterial superinfection occurs in up to 25% of cases, involving both gram-positive and gram-negative organisms 6

Felon

• A felon is an abscess of the distal pulp of the fingertip that causes severe throbbing pain and swelling 3
• This represents a more serious infection requiring prompt recognition, as delayed treatment can lead to significant morbidity 2, 3

Cellulitis

• Diffuse spreading skin infection affecting the fingertip can cause pain, edema, redness, and heat 5
• Organisms enter through small breaks in the skin that may be clinically inapparent 5

Traumatic Causes

Direct Fingertip Injury

• Mechanical trauma to the fingertip and nailbed causes immediate pain and requires treatment to minimize discomfort and speed healing 7
• The fingertip serves as the interface between humans and environmental hazards, making it the most frequent site of hand infections following injury 2

Nail Apparatus Trauma

• Injury to the nail plate, nail bed, or periungual tissues can cause persistent pain on the dorsal fingertip 7
• Subungual hematomas or nail plate separation (onycholysis) following trauma produce significant discomfort 5

Inflammatory and Drug-Induced Causes

Medication-Related Paronychia

• EGFR inhibitors, MEK inhibitors, and mTOR inhibitors used in cancer treatment commonly cause painful inflammatory paronychia affecting fingernails more than toenails 5, 6
• This represents an inflammatory process from altered keratinocyte differentiation rather than primary infection, though secondary bacterial infection develops in 25% of cases 6
• The periungual skin becomes swollen, erythematous, and painful with prominent gaps between the fold and nail plate 5

Taxane-Induced Nail Changes

• Chemotherapy agents (docetaxel, paclitaxel) cause painful onycholysis with nail plate detachment, subungual abscesses, and hemorrhages 5
• Pain occurs due to acute trauma, progression of detachment, or development of subungual hematoma 5

Fungal Causes

Onychomycosis with Secondary Changes

• Candida nail infection can cause pain, particularly when pressure is applied or the nail is moved—a distinguishing feature from dermatophyte infections 5
• Distal Candida nail infection with onycholysis and subungual hyperkeratosis causes discomfort, especially in patients with underlying vascular problems like Raynaud phenomenon 5

Neuropathic Causes

Peripheral Neuropathy

• Damage to peripheral sensory neurons from metabolic imbalance, autoimmune diseases, or viral infections can cause cutaneous neuropathic pain affecting the fingertips 8
• Distorted or amplified nociceptor signaling results in chronic pain and extreme sensitivity to light touch (allodynia) 8

Important Clinical Pitfalls

• Do not assume all periungual pain represents bacterial infection—drug-induced paronychia from cancer therapies is primarily inflammatory and requires topical corticosteroids rather than antibiotics unless secondary infection is confirmed 6
• Distinguish between Candida and bacterial paronychia—pain with nail movement suggests Candida, which requires antifungal rather than antibacterial therapy 5, 4
• Recognize early felons—these require more aggressive intervention than simple paronychia to prevent significant morbidity 2, 3
• Consider systemic causes—finger pain may be the first manifestation of serious systemic illness including rheumatic disease or vascular emergencies requiring prompt intervention 9