Identifying Skin Conditions: Psoriasis, Cancer, and Look-alikes

February 7, 2024

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Psoriasis is a common chronic autoimmune condition that causes skin inflammation and manifests as thick, scaly, red plaques on the body. It can range from mild with limited skin involvement to severe cases affecting over 10% of the body surface area.

While psoriasis itself is not contagious, this distressing condition is associated with multiple comorbidities including psoriatic arthritis, cardiovascular disease, diabetes, depression, and potentially even cancer. The links between psoriasis and cancer continue to be actively researched.

Overview of Psoriasis and Cancer

Cancer arises when genetic mutations trigger cells to proliferate abnormally and spread uncontrollably. Skin cancer specifically develops from cancerous mutations in skin cell DNA most often stemming from ultraviolet radiation damage.

So how are psoriasis and cancer connected? Research indicates psoriasis may predispose patients to certain types of cancer, especially lymphomas and skin cancers. Proposed reasons include:

  • Chronic inflammation in psoriasis may promote cancer cell development
  • Psoriasis treatments can weaken immunity and skin protection increasing cancer risk
  • Shared genetic susceptibilities between psoriasis and some cancers

However, study evidence remains inconclusive regarding the exact link between psoriasis and cancer risk. Let’s analyze the current state of evidence on this emerging association.

Recent largescale studies reveal modest correlations between psoriasis and risk of certain cancers, but overall research data is mixed.

A 2020 meta-analysis compiling data from over 700,000 psoriasis patients found a slightly elevated risk of lymphoma and squamous cell skin carcinoma compared to the general population. However, there was no increased risk found for common solid tumors like breast, colorectal or prostate cancer.

Specific findings include:

  • 10% higher lymphoma risk
  • 30% greater risk of squamous cell skin cancer
  • No correlation with lung, pancreatic, uterine, kidney cancers
  • 15-20% more prone to develop basal cell skin carcinoma

So psoriatic patients do seem to have higher odds for lymphoproliferative blood cancers and non-melanoma skin cancers.

But does psoriasis treatment further increase this risk?

Impact of Psoriasis Treatment on Cancer Risk

Powerful systemic psoriasis therapies that modulate the immune response may influence susceptibility to malignancies. These include:

  • Biologics like TNF-alpha inhibitors adalimumab, infliximab
  • Immunosuppressants such as methotrexate, cyclosporine
  • Phototherapy using concentrated UV light sources

By suppressing immune activity against tumors or promoting DNA damage, such treatments could potentially facilitate cancer development studies suggest.

Phototherapy has the most definitive cancer link, with increased skin cancer risk proportional to the number of PUVA treatments. Hence regular skin checks are vital during phototherapy.

Biologics appear quite safe but long term risks require further observation. Overall, while correlations exist, psoriasis itself likely confers higher inherent cancer susceptibility rather than just the treatment modalities.

Psoriasis vs Skin Cancer

Despite associations between psoriasis and some skin malignancies, psoriatic plaques are fundamentally distinct from actual skin cancers.

But early on, appearances may overlap. Let’s examine how to distinguish patches of psoriasis from potential skin cancer symptoms:

FeaturesPsoriasisSkin Cancer
LocationSymmetrical areas like elbows, knees, scalpAsymmetrical, often sun-exposed areas
BorderClearly defined edgeIrregular, uneven borders
ColorBright to dusky redVaried colors including brown, black, multi-hued
SensationUsually itchy or soreTypically not itchy/painful when small
ThicknessThick, firm plaquesFlat to nodular lesions
Change over timeStable appearanceProgressively enlarging
HealingHeals without scarringDevelops ulceration, bleeding and scarring

So while psoriasis causes well-demarcated red plaques, cancerous skin lesions tend to show concerning characteristics like asymmetry, color variation, and progressive enlargement.

Skin biopsies are often needed when clinical uncertainty exists regarding the exact diagnosis.

Keratosis Pilaris vs Psoriasis

Keratosis pilaris (KP) is another common harmless skin disorder that shares similarities with psoriasis. However, there are subtle distinguishing features:

  • KP manifests as small rough bumps rather than large smooth plaques
  • It lacks scaling, cracking or bleeding seen in psoriasis
  • Occurs predominantly on the upper outer arms, thighs and buttocks
  • Genetic predisposition towards KP exists

Hence while both conditions cause skin irritation, KP results from excess keratin accumulation rather than autoimmune inflammation like psoriasis. Treatment approaches also accordingly differ.

Diagnosis and Management

Careful evaluation of clinical morphology, symptom quality and distribution pattern of suspicious skin lesions is pivotal for accurate diagnosis.

  • For psoriasis, look for symmetrically distributed, thick red plaques covered by silvery-white scales
  • Skin cancers often appear asymmetrical moles or lesions with concerning features like pigment variation or bleeding
  • KP causes disseminated small rough bumps on the upper outer arms and thighs

Once the diagnosis is established, specific management can be initiated:

  • Topical treatments, phototherapy and systemic medications for psoriasis plaques
  • Surgical excision, chemotherapy or radiation for malignant skin cancers
  • Moisturizers, retinoids or urea creams to alleviate KP discoloration and roughness

Monitoring for skin cancer is especially vital in psoriasis patients on long term immunosuppressive treatment.


In summary, associations exist between psoriasis, especially severe forms, and slightly higher rates of certain cancers- specifically lymphoma and squamous cell carcinoma. Psoriasis treatment with UV, immunosuppressants and biologics could also influence susceptibility. Hence monitoring for malignancies may be beneficial alongside psoriasis management. Differentiating early skin cancers from conditions like plaque psoriasis and keratosis pilaris is key to ensure timely diagnosis and treatment of any suspicious skin lesions.

Frequently Asked Questions

Does psoriasis increase the risk of skin cancer?

Some research shows psoriasis may be linked to a moderately elevated risk of non-melanoma skin cancers like squamous cell carcinoma and possibly basal cell carcinoma. Reasons may involve chronic skin inflammation and immune-altering psoriasis treatment. Monitoring for atypical skin lesions is therefore important.

What cancers are most common in psoriasis patients?

Largescale studies indicate people with psoriasis have slightly higher rates of lymphomasquamous cell carcinoma and possibly basal cell skin cancer versus the general population. But large analysis found no definite increased occurrence of common solid tumors.

Can early skin cancers mimic psoriasis plaques?

In some instances, early squamous cell carcinoma lesions can resemble psoriatic plaques. Features like asymmetry, irregular borders, color variation, bleeding, enlargement over time and itchiness help distinguish malignant lesions from chronic psoriatic plaques.

No, keratosis pilaris is a separate common, harmless disorder caused by excess keratin clogging hair follicles and not autoimmune inflammation. While both conditions may cause dry rough skin, KP has small bumps rather than large raised plaques and lacks scaling seen in psoriasis.

Do psoriasis treatments themselves increase cancer risk?

Possibly. Phototherapy, biologics and immunosuppressants for psoriasis may inhibit immune surveillance for cancer cells and promote DNA damage contributing to malignancy development. So skin checks and monitoring are important, especially with phototherapy which has the strongest skin cancer link.

Key Takeaways

  • Associations exist between psoriasis and slightly elevated lymphoma and non-melanoma skin cancer risks.
  • In some cases, appearance of early squamous cell skin cancer can resemble psoriatic plaques necessitating biopsy confirmation.
  • Keratosis pilaris differs from psoriasis with small rough bumps without large scaling plaques due to different underlying pathogeneses.
  • Psoriasis treatments like phototherapy, biologics and immunosuppressants may heighten susceptibility to skin cancers underscoring the importance of monitoring.


  1. Takeshita J, Shin DB, Ogdie A, et al. Risk of serious infection and cancer among patients with psoriasis: a population-based cohort study. Ann Rheum Dis. 2020;79(3):339-344.
  2. Padilla Madrid J, Torres T, Noguera-Morel L, Hernández-Martín Á. Unmet needs in the management of psoriasis associated comorbidities. J Eur Acad Dermatol Venereol. 2022;36(1):49-63.
  3. Murase JE, Lee EE, Koo J. Psoriasis and skin cancer: synergism between PUVA, immunosuppressants, and biologics. Dermatol Clin. 2015;33(1):89-98.
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