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Year : 2019  |  Volume : 85  |  Issue : 1  |  Page : 82-83

Author's reply

BB Mahajan 
 Professor, Dermatology, Venereology and Leprosy, Govt. Medical College, Amritsar, Punjab, India

Correspondence Address:
Dr. B B Mahajan
Professor, Dermatology, Venereology and Leprosy, Govt. Medical College, Amritsar, Punjab

How to cite this article:
Mahajan B B. Author's reply.Indian J Dermatol Venereol Leprol 2019;85:82-83

How to cite this URL:
Mahajan B B. Author's reply. Indian J Dermatol Venereol Leprol [serial online] 2019 [cited 2020 Sep 19 ];85:82-83
Available from: http://www.ijdvl.com/text.asp?2019/85/1/82/246723

Full Text


Regarding first query:

Therapeutic efficacy of a drug is defined as the maximum response of a drug irrespective of the drug concentration.[1],[2] So, the concentration of a drug in relation to its half-life should not be taken into consideration for its therapeutic efficacy.

In our study, intramatricial injection of these drugs corrects the defective keratinization at the level of nail matrix and the response is visualized and evaluated on the finger nail plate that grows at a rate of 3 mm/month, taking a total of 24 weeks.

All the drugs used are not depot agents; hence the therapeutic efficacy of these drugs in nail psoriasis should not be related to elimination pharmacokinetics.

Regarding second query:

Koebnerization can occur in nail psoriasis, as commonly observed in certain occupations such as manual laborers, typists, farmers and housewives who are exposed to repeated nail trauma. Hence, physical trauma such as nail biting, nail picking, manicure, wearing tight shoes, clearing subungual debris are discouraged in nail psoriasis.[3],[4]

Although, reverse koebnerization in nail psoriasis has not been reported in the literature till date, yet further studies are required to compare the efficacy of intramatricial injection therapy with that of the needle tip trauma to the nail matrix alone, without injecting any drug. With needle tip injury, both koebnerization and reverse koebnerization are theoretically possible, but needs to be substantiated by further studies.

Regarding third query:

In our study, two injections of the respective drugs have been given 6 weeks apart, which has possibly only corrected the defective keratinization of nail matrix rather than causing the growth arrest of the nail matrix as a whole resulting in Beau's lines.

The chances of appearance of Beau's lines may increase with weekly injections rather than giving two injections 6 weeks apart.

To conclude, we highly appreciate the queries and postulate that intramatricial injection of a drug should be recommended at 6 weeks' intervals rather than at more frequent intervals to maximize their efficacy and minimize the adverse effects in psoriatic finger nails.

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Conflicts of interest

There are no conflicts of interest.


1Tripathi KD, Tripathi M, editors. Pharmacodynamics: Mechanism of drug action; receptor pharmacology. In: Essentials of Medical Pharmacology. 6th ed. New Delhi: Jaypee Brothers Medical Publishers; 2008. p. 54-5.
2Clark MA, Finkel R, Rey JA, Whalen K, editors. Drug-receptor interactions and pharmacodynamics. In: Lippincott's Illustrated Reviews: Pharmacology. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2012. p. 30-1.
3de Berker D. Management of psoriatic nail disease. Semin Cutan Med Surg 2009;28:39-43.
4Pasch MC. Nail psoriasis: A review of treatment options. Drugs 2016;76:675-705.


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