Photo Quiz

Severely Callused Hands and Feet


Am Fam Physician. 2020 May 15;101(10):623-624.

A 30-year-old man presented to the family medicine clinic as a new patient. He had a long history of uncontrollable thick callus formations on both hands and feet, which began when he was about six months old. His mother noticed thickened skin and blisters on his knees and hands when he started crawling. By 13 months old, his toenails had thickened and were removed.

Physical examination revealed severe callus formation and a marked keratinized, yellow skin proliferation over the soles of both feet, with skin fissures and cracking. Similar hyperkeratotic lesions were also seen on the palms of both hands (Figure 1 and Figure 2). Hypertrophy of the nail beds was present on both feet and hands.






Based on this patient's history and physical findings, which one of the following is the most likely diagnosis?

A. Epidermolysis bullosa.

B. Ichthyosis vulgaris.

C. Pachyonychia congenita.

D. Palmoplantar psoriasis.


The answer is C: pachyonychia congenita. Pachyonychia congenita is an extremely rare genetic skin disorder caused by a mutation in one of the keratin genes (KRT6A, KRT6B, KRT6C, KRT16, KRT17).1 It is inherited in an autosomal dominant pattern. The most common and striking features of the condition are severe callus formation and painful blistering on the soles and palms. A triad of hypertrophic nail dystrophy, plantar/palmar hyperkeratosis, and severe plantar pain occurs across all types. The age of onset is variable, but most cases are clinically apparent during the first few years of life. Adult onset is rare.

Lesions typically begin to develop when a child starts weight-bearing and walking, with diffuse or focal hyperkeratosis of the soles and palms and underlying frictional blisters that cause severe pain. Additional clinical findings may include oral leukoplakia, follicular hyperkeratosis on elbows and knees, palmoplantar hyperhidrosis, and cutaneous cysts.2 The diagnosis is made clinically with the presence of the classic triad. The diagnosis

Address correspondence to Sam Longfellow, DO, at Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.


show all references

1. Foundation for Ichthyosis and Related Skin Types. Pachyonychia congenita: a patient's perspective. Accessed October 8, 2019.

2. Leachman SA, Kaspar RL, Fleckman P, et al. Clinical and pathological features of pachyonychia congenita. J Investig Dermatol Symp Proc. 2005;10(1):3–17.

3. Sprecher E, Smith FJD. UpToDate. Pachyonychia congenita. Accessed October 10, 2019.

4. Porter RM, Bravo AA, Smith FJD. Management of plantar keratodermas: lessons from pachyonychia congenita. J Am Podiatr Med Assoc. 2017;107(5):428–435.

5. Fitzpatrick TB. Color Atlas and Synopsis of Clinical Dermatology. McGraw Hill Higher Education; 2007.

6. Habif TP. Clinical Dermatology: a Color Guide to Diagnosis and Therapy. 3rd ed. Mosby; 1996.

This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.

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